Patent Publication Number: US-2020277350-A1

Title: Proteinaceous heterodimer and use thereof

Description:
BACKGROUND 
     Although immune responses against tumor antigens can be detected (Disis et al. (1997) J. Clin. Oncol. 15: 3363-3367), malignant cells causing diseases often fail to elicit an immune response that leads to rejection. Studies have demonstrated that it is possible to enhance the immunogenicity of tumor cells by introducing immunoregulatory molecules such as cytokines and costimulatory molecules into them. However, the expression and stability of the immunoregulatory molecules introduced are often far from satisfactory. Immunoregulators, such as cytokines, produced by cells of the immune system can, directly or indirectly, activate the cells of the adaptive immune response and can play an important role in eliciting protective antitumor immunity. The innate immune system can be triggered by bacterial products or “danger” signals that lead to the release of proinflammatory cytokines, such as IFN-α, TNF-α, and interleukins. 
     Multiple studies have shown that immunoregulators (such as interleukins) may be useful in exerting antitumor effects in both animal models and cancer patients. However, interleukins have a relatively short serum half-life in the body. For example, the half-life of IL10 in mice as measured by in vitro bioassay or by efficacy in the septic shock model system (see Smith et al., Cellular Immunology 173: 207-214 (1996)) is about 2 to 6 hours. A loss of interleukin activity may be due to several factors, including renal clearance, proteolytic degradation and monomerization in the blood stream. 
     As such, there is a considerable need for long-acting immunoregulators, which could be produced with relatively high yield at industrial-scale and would have a relatively long half-life in vivo to be useful in treating disorders or diseases related with hyper proliferation of cells and/or tissues, e.g., various neoplasms, different types of cancer, and/or tumors. In addition, the yield of such a product shall be sufficiently high to avoid complicated purification process and/or to reduce the risks associated with undesired impurities. 
     SUMMARY 
     The present disclosure addresses such a need and provides related advantages as well. The present disclosure encompasses proteinaceous heterodimers useful in inhibiting tumor growth, and compositions, medicaments and/or kits comprising the proteinaceous heterodimers. In addition, the present disclosure provides protein mixtures comprising said proteinaceous heterodimers and with little (if any) undesired impurities (such as undesired protein homodimers or protein aggregates). The disclosure also provides methods to produce the proteinaceous heterodimers or protein mixtures, as well as pharmaceutical uses of the proteinaceous heterodimers and/or protein mixtures in inhibiting tumor growth, including but not limited to treatment of cancers. 
     In one aspect, the present disclosure provides a proteinaceous heterodimer comprising a first monomeric member and a second monomeric member different from said first monomeric member, wherein the first monomeric member comprises a first Fc subunit, the second monomeric member comprises a second Fc subunit, and the first monomeric member associates with the second monomeric member to form the heterodimer through complexation of the first Fc subunit with the second Fc subunit; wherein the proteinaceous heterodimer further comprises one or more interleukins fused to the first Fc subunit and/or the second Fc subunit; and wherein the proteinaceous heterodimer does not comprise any antibody heavy chain variable region or any antibody light chain variable region exhibiting binding specificity to a tumor antigen. 
     In some embodiments, the proteinaceous heterodimer according to the present disclosure, wherein the one or more interleukins is fused to an amino-terminal amino acid and/or a carboxy-terminal amino acid of the first Fc subunit and/or the second Fc subunit. 
     In some embodiments, the proteinaceous heterodimer according to the present disclosure, which comprises two or more interleukins, and wherein the two or more interleukins form one or more interleukin dimers, with each interleukin dimer comprising two interleukins fused to each other. 
     In some embodiments, the proteinaceous heterodimer according to any one of the present disclosure, wherein at least one of the one or more interleukins is IL10. 
     In some embodiments, the proteinaceous heterodimer according to any one of the present disclosure, wherein the one or more interleukin dimers comprise at least one IL10 dimer, and the IL10 dimer comprises two IL10. 
     In some embodiments, the proteinaceous heterodimer according to any one of the present disclosure, wherein the first Fc subunit and/or said second Fc subunit is from an IgG molecule. In some embodiments, the proteinaceous heterodimer according to the present disclosure, wherein the IgG is a human IgG1. 
     In some embodiments, the proteinaceous heterodimer according to any one of the present disclosure, wherein the first Fc subunit is different from the second Fc subunit, and the first and/or second Fc subunit comprises a modification promoting heterodimerization between the first Fc subunit and the second Fc subunit. 
     In some embodiments, the proteinaceous heterodimer according to the present disclosure, wherein the first Fc subunit comprises a first modification, the second Fc subunit comprises a second modification, and the first modification and the second modification comprise an amino acid substitution at group of positions selected from any following groups: 1) the first modification: Y349 and T366; and the second modification: D356, T366, L368, Y407 and F405; 2) the first modification: Y349, T366 and F405; and the second modification: D356, T366, L368 and Y407; 3) the first modification: Y349, T366 and K409; and the second modification: D356, T366, L368, Y407 and F405; 4) the first modification: Y349, T366, F405, K360 and Q347; and the second modification: D356, T366, L368, Y407 and Q347; 5) the first modification: Y349, T366, F405 and Q347; and the second modification: D356, T366, L368, Y407, K360 and Q347; 6) the first modification: Y349, T366, K409, K360 and Q347; and the second modification: D356, T366, L368, Y407, F405 and Q347; 7) the first modification: Y349, T366, K409 and Q347; and the second modification: D356, T366, L368, Y407, F405, K360 and Q347; 8) the first modification: T366, K409 and K392; and the second modification: T366, L368, Y407, D399 and F405; 9) the first modification: T366 and K409; and the second modification: T366, L368, Y407 and F405; 10) the first modification: T366, K409 and Y349; and the second modification: T366, L368, Y407, F405 and E357; 11) the first modification: T366, K409, Y349 and 5354; and the second modification: T366, L368, Y407, F405 and E357; 12) the first modification: T366 and F405; and the second modification: T366, L368, Y407 and K409; 13) the first modification: T366, F405 and D399; and the second modification: T366, L368, Y407, K409 and K392; 14) the first modification: T366, F405 and Y349; and the second modification: T366, L368, Y407, K409 and E357; 15) the first modification: T366, F405, Y349 and S354; and the second modification: T366, L368, Y407, K409 and E357; wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     In some embodiments, the proteinaceous heterodimer according to any one of the present disclosure, wherein at least one of the one or more interleukins is fused to an amino-terminal amino acid of the second Fc subunit. 
     In some embodiments, the proteinaceous heterodimer according to the present disclosure, wherein in the second monomeric member, at least two of the one or more interleukins are fused to each other to form an interleukin dimer, and the interleukin dimer is further fused to the amino-terminal amino acid of the second Fc subunit. 
     In some embodiments, the proteinaceous heterodimer according to any one of the present disclosure, wherein in the second monomeric member, at least two of the one or more interleukins are fused to each other to form an interleukin dimer, and the interleukin dimer is further fused to the carboxyl-terminal amino acid of the second Fc subunit. 
     In some embodiments, the proteinaceous heterodimer according to any one of the present disclosure, wherein the first monomeric member does not comprise any interleukin. 
     In some embodiments, the proteinaceous heterodimer according to any one of the present disclosure, wherein the first monomeric member consists of the first Fc subunit. 
     In some embodiments, the proteinaceous heterodimer according to any one of the present disclosure, wherein at least one of the one or more interleukins is fused to an amino-terminal amino acid of the first Fc subunit. 
     In some embodiments, the proteinaceous heterodimer according to the present disclosure, wherein in the first monomeric member, at least two of the one or more interleukins are fused to each other to form an interleukin dimer, and the interleukin dimer is further fused to the amino-terminal amino acid of the first Fc subunit. 
     In some embodiments, the proteinaceous heterodimer according to any one of the present disclosure, wherein the second monomeric member does not comprise any interleukin. 
     In some embodiments, the proteinaceous heterodimer according to any one of the present disclosure, wherein the second monomeric member consists of the second Fc subunit. 
     In another aspect, the present disclosure provides an isolated nucleic acid or isolated nucleic acids encoding the proteinaceous heterodimer according to any one of the present disclosure. 
     In another aspect, the present disclosure provides a vector or vectors comprising the isolated nucleic acid or isolated nucleic acids according to the present disclosure. 
     In another aspect, the present disclosure provides an isolated host cell comprising the isolated nucleic acid or isolated nucleic acids according to the present disclosure or the vector or vectors according to the present disclosure. 
     In another aspect, the present disclosure provides a protein mixture, comprising: 1) the proteinaceous heterodimer according to any one of the present disclosure; 2) a first homodimer formed by two identical copies of the first monomeric member according to any one of the present disclosure; and 3) a second homodimer formed by two identical copies of the second monomeric member according to any one of the present disclosure; wherein a percentage of said proteinaceous heterodimer in the protein mixture is at least 50%. 
     In another aspect, the present disclosure provides a pharmaceutical composition comprising the proteinaceous heterodimer according to any one of the present disclosure, or the protein mixture according to the present disclosure and optionally a pharmaceutically acceptable excipient. 
     In another aspect, the present disclosure provides a use of the proteinaceous heterodimer according to any one of the present disclosure, or the protein mixture according to the present disclosure in the manufacture of a medicament and/or a kit for inhibiting growth of a tumor or a tumor cell and/or for treating cancer in a subject in need thereof. 
     In another aspect, the present disclosure provides a method for producing a proteinaceous heterodimer according to any one of the present disclosure, comprising (i) culturing the host cell of the present disclosure under conditions to effect expression of the proteinaceous heterodimer, and (ii) harvesting the expressed proteinaceous heterodimer or a protein mixture comprising said proteinaceous heterodimer. 
     Additional aspects and advantages of the present disclosure will become readily apparent to those skilled in this art from the following detailed description, wherein only illustrative embodiments of the present disclosure are shown and described. As will be realized, the present disclosure is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive. 
     INCORPORATION BY REFERENCE 
     All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features of the disclosure are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present disclosure will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the disclosure are utilized, and the accompanying drawings of which: 
         FIGS. 1A-1D  illustrate examples of the proteinaceous heterodimers according to the present application. 
         FIGS. 2A-2F  illustrate the purification result of the proteinaceous heterodimers of the present disclosure, as shown by SDS-PAGE and SEC-HPLC analysis. 
         FIG. 3  illustrates the binding affinity to human IL10R1 proteins (ELISA). 
         FIG. 4  illustrates the enhancement of proliferation of MC/9 cells. 
         FIGS. 5A-5B  illustrate the effect of tumor control of the proteinaceous heterodimers of the present disclosure. 
         FIGS. 6A-6B  illustrate the comparison between the high and low concentrations of the proteinaceous heterodimers in tumor control. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     Before the embodiments of the disclosure are described, it is to be understood that such embodiments are provided by way of example only, and that various alternatives to the embodiments of the disclosure described herein may be employed in practicing the disclosure. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the disclosure. 
     Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosure, suitable methods and materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the disclosure. 
     The singular form “a,” “an” and “the,” as used herein, generally include plural references unless the context clearly dictates otherwise. 
     The term “proteinaceous,” as used herein, generally refers to a material or molecule that is of, relating to, resembling, or being a polypeptide or a protein. For example, a proteinaceous heterodimer of the present disclosure may be a heterodimer protein, or a heterodimer comprising two or more polypeptides. 
     The term “heterodimer,” as used herein, generally refers to a molecule (e.g. a proteinaceous molecule) composed of two different members. The two members of a heterodimer may differ in structure, function, activity and/or composition. For example, the two different members may comprise polypeptides differing in the order, number, or kind of amino acid residues forming these polypeptides. Each of the two different members of a heterodimer may independently comprise one, two or more units, polypeptide chains, or moieties. 
     The term “targeting moiety,” as used herein, generally refers to a molecule, complex or aggregate, that binds specifically, selectively or preferentially to a target molecule, cell, particle, tissue or aggregate. For example, a targeting moiety may be an antibody, antigen-binding antibody fragment, bispecific antibody or other antibody-based molecule or compound. Other examples of targeting moieties may include, but are not limited to, aptamers, avimers, receptor-binding ligands, nucleic acids, biotin-avidin binding pairs, binding peptides or proteins, etc. The terms “targeting moiety” and “binding moiety” are used interchangeably herein. 
     The term “tumor antigen,” as used herein, generally refers to an antigenic substance produced in or by tumor cells, which may have an ability to trigger an immune response in a host. For example, a tumor antigen may be a protein, a polypeptide, a peptide, or a fragment thereof, which constitutes part of a tumor cell and is capable of inducing tumor-specific cytotoxic T lymphocytes. A tumor antigen peptide may be a peptide that is generated as a result of degradation of the tumor antigen in a tumor cell and can induce or activate tumor-specific cytotoxic T lymphocytes upon being expressed on cell surface by binding to an HLA molecule. In some embodiments, the term “tumor antigen” may also refer to biomolecules (e.g., proteins, carbohydrates, glycoproteins, etc.) that are exclusively or preferentially or differentially expressed on a cancer cell and/or are found in association with a cancer cell and thereby provide targets preferential or specific to the cancer. For example, the preferential expression can be preferential expression as compared to any other cell in the organism, or preferential expression within a particular area of the organism (e.g. within a particular organ or tissue). 
     The terms “tumor antigen epitope” and “tumor antigen determinant” are used interchangeably herein and generally refer to the site of an amino acid sequence present in a tumor antigen that induces tumor-specific cytotoxic T lymphocytes. 
     The term “expression yield” as used in the context of proteinaceous heterodimers herein, generally refers to an amount of a proteinaceous heterodimer being produced in functional form upon expression, e.g., when expressed by a host cell. 
     The term “dimerization sequence” as used herein, generally refers to an amino acid sequence capable of forming a dimer, or undergoing dimerization. In some embodiments, a dimer is a heterodimer formed by two different members. In some cases, the two different members of a heterodimer may comprise different dimerization sequences. 
     The term “heterodimerization” as used herein, generally refers to the process of forming a heterodimer between two different members (e.g., two different polypeptides), such as through complexation, association, or aggregation, with or without formation of covalent bonds between the two different members. 
     The term “covalent bond” as used herein, generally refers to a chemical bond formed between atoms by the sharing of electrons. For example, a covalent bond may be polar or non-polar. In some embodiments, a covalent bond is a disulfide bond. 
     The term “non-covalent pairwise affinity” as used herein, generally refers to that dimerization sequences or heterodimerization sequences capable of binding each other via non-covalent interaction, e.g., via ion pairs, hydrogen bonds, dipole-dipole interactions, charge transfer interactions, n-n interactions, cation-n-electron interactions, van der Waals interactions and disperse interactions, hydrophobic (lipophilic) interactions, complex formation (e.g., complex formation of transition metal cations), or a combination of these interactions. 
     The term “linker,” as used herein, generally refers to a synthetic amino acid sequence that connects or links two polypeptide sequences, e.g., that link two polypeptide domains. A linker may connect two amino acid sequences via peptide bonds. In some embodiments, a linker of the present disclosure connects a biologically active moiety to a second moiety in a linear sequence. 
     The terms “polypeptide” “peptide” and “protein” are used interchangeably herein to refer to polymers of amino acids of any length. The polymer may be linear or branched, it may comprise modified amino acids, and it may be interrupted by non-amino acids. The terms also encompass an amino acid polymer that has been modified, for example, by disulfide bond formation, glycosylation, lipidation, acetylation, phosphorylation, or any other manipulation, such as conjugation with a labeling component. The terms may apply to amino acid polymers in which one or more amino acid residue is an artificial chemical analogue of a corresponding naturally occurring amino acid, as well as to naturally occurring amino acid polymers. The terms may also include variants on the traditional peptide linkage joining the amino acids making up the polypeptide. For example, the “peptides”, “polypeptides” and “proteins” may be chains of amino acids whose alpha carbons are linked through peptide bonds. The terminal amino acid at one end of the chain (amino terminal) therefore may have a free amino group, while the terminal amino acid at the other end of the chain (carboxy terminal) may have a free carboxyl group. As used herein, the term “amino terminus” (abbreviated N-terminus) generally refers to the free a-amino group on an amino acid at the amino terminal of a peptide or to the a-amino group (amino group when participating in a peptide bond) of an amino acid at any other location within the peptide. Similarly, the term “carboxy terminus” generally refers to the free carboxyl group on the carboxy terminus of a peptide or the carboxyl group of an amino acid at any other location within the peptide. Peptides may also include essentially any poly-amino acid including, but not limited to peptide mimetics such as amino acids joined by a ether as opposed to an amide bond. 
     The term “amino acid” as used herein, generally refers to either natural and/or unnatural or synthetic amino acids, including but not limited to, the D or L optical isomers or both, amino acid analogs and peptidomimetics. Standard single or three letter codes are used to designate amino acids. 
     The term “natural L-amino acid” as used herein, generally refers to the L optical isomer forms of glycine (G), proline (P), alanine (A), valine (V), leucine (L), isoleucine (I), methionine (M), cysteine (C), phenylalanine (F), tyrosine (Y), tryptophan (W), histidine (H), lysine (K), arginine (R), glutamine (Q), asparagine (N), glutamic acid (E), aspartic acid (D), serine (S), and threonine (T). 
     The term “non-naturally occurring” as used herein, generally refers to polypeptide or polynucleotide sequences that do not have a counterpart to, are not complementary to, or do not have a high degree of homology with a wild-type or naturally-occurring sequence (e.g., those found in a subject). For example, a non-naturally occurring polypeptide or fragment may share less than 99%, 98%, 95%, 90%, 80%, 70%, 60%, 50% or even less amino acid sequence identity as compared to a natural sequence when suitably aligned. Alternatively, a non-naturally occurring polypeptide or fragment may share more than 99%, 98%, 95%, 90%, 80%, 70%, 60%, 50% or even more amino acid sequence identity as compared to a natural sequence when suitably aligned. 
     The terms “hydrophilic” and “hydrophobic,” as used herein, generally refer to the degree of affinity that a substance has with water. A hydrophilic substance has a strong affinity for water, tending to dissolve in, mix with, or be wetted by water, while a hydrophobic substance substantially lacks affinity for water, tending to repel and not absorb water and tending not to dissolve in or mix with or be wetted by water. Amino acids can be characterized based on their hydrophobicity. A number of scales have been developed. An example is a scale developed by Levitt, M, et al., J Mol Biol (1976) 104: 59, which is listed in Hopp, T P, et al., Proc Natl Acad Sci U S A (1981) 78: 3824. Examples of “hydrophilic amino acids” are arginine, lysine, threonine, alanine, asparagine, and glutamine. Of particular interest are the hydrophilic amino acids aspartate, glutamate, and serine, and glycine. Examples of “hydrophobic amino acids” are tryptophan, tyrosine, phenylalanine, methionine, leucine, isoleucine, and valine. 
     The term “fragment” when used in the context of a proteinaceous molecule (e.g., a polypeptide or a protein), generally refers to a truncated form of a native biologically active protein that may or may not retain a portion of the therapeutic and/or biological activity. 
     The term “variant” when used in the context of a proteinaceous molecule (e.g., a polypeptide or a protein), generally refers to a proteinaceous molecule with sequence homology to the native biologically active protein that retains at least a portion of the therapeutic and/or biological activity of the biologically active protein. For example, a variant protein may share at least 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% amino acid sequence identity compared with the reference biologically active protein. In some embodiments, the “variant” may include proteins modified deliberately, as for example, by site directed mutagenesis, synthesis of the encoding gene, insertions, or accidentally through mutations. 
     The terms “conjugated”, “linked”, “fused”, and “fusion” are used interchangeably herein, and generally refer to the joining together of two or more chemical elements, sequences or components, e.g., by means including chemical conjugation or recombinant means. For example, a promoter or enhancer is operably linked to a coding sequence if it effects the transcription of the sequence. Generally, “operably linked” means that the DNA sequences being linked are contiguous, and in reading phase or in-frame. An “in-frame fusion” refers to the joining of two or more open reading frames (ORFs) to form a continuous longer ORF, in a manner that maintains the correct reading frame of the original ORFs. Thus, the resulting “fusion polypeptide” is a single protein containing two or more fragments that correspond to polypeptides encoded by the original ORFs (which segments are not normally so joined in nature). The “fusion site” refers to the sequence where the two or more fragments are joined together. In some cases, the fusion site can be a sequence that is identical to sequences in the two or more fragments being joined. In some cases, the fusion site can further comprise a gap segment that is not identical to either of the sequences of the two or more fragments being joined. 
     In the context of polypeptides, a “linear sequence” or a “sequence” is an order of amino acids in a polypeptide in an amino to carboxyl terminus direction in which residues next to each other in the sequence are contiguous in the primary structure of the polypeptide. A “partial sequence” is a linear sequence forming part of a polypeptide that is known to comprise additional residues in one or both directions. 
     The terms “polynucleotides”, “nucleic acids”, “nucleotides” and “oligonucleotides” are used interchangeably herein, and they generally refer to a polymeric form of nucleotides of any length, either deoxyribonucleotides or ribonucleotides, or analogs thereof. Polynucleotides may have any three-dimensional structure, and may perform any function, known or unknown. The following are non-limiting examples of polynucleotides: coding or non-coding regions of a gene or gene fragment, loci (locus) defined from linkage analysis, exons, introns, messenger RNA (mRNA), transfer RNA, ribosomal RNA, ribozymes, cDNA, recombinant polynucleotides, branched polynucleotides, plasmids, vectors, isolated DNA of any sequence, isolated RNA of any sequence, nucleic acid probes, and primers. A polynucleotide may comprise modified nucleotides, such as methylated nucleotides and nucleotide analogs. If present, modifications to the nucleotide structure may be imparted before or after assembly of the polymer. The sequence of nucleotides may be interrupted by non-nucleotide components. A polynucleotide may be further modified after polymerization, such as by conjugation with a labeling component. 
     The terms “gene” and “gene fragment” are used interchangeably herein and generally refer to a polynucleotide containing at least one open reading frame that is capable of encoding a particular protein after being transcribed and translated. A gene or gene fragment may be genomic or cDNA, as long as the polynucleotide contains at least one open reading frame, which may cover the entire coding region or a segment thereof A “fusion gene” is a gene composed of at least two heterologous polynucleotides that are linked together. 
     The term “antibody” as used herein, generally refers to a protein comprising one or more polypeptides substantially encoded by immunoglobulin genes or fragments of immunoglobulin genes. The immunoglobulin genes may include the kappa, lambda, alpha, gamma, delta, epsilon and mu constant region genes, as well as myriad immunoglobulin variable region genes. As used herein, light chains may be classified as either kappa or lambda. Heavy chains may be classified as gamma, mu, alpha, delta, or epsilon, which in turn define the immunoglobulin classes, IgG, IgM, IgA, IgD and IgE, respectively. An antibody as used in the present disclosure may have a structural unit comprising a tetramer. Each tetramer may be composed of two identical pairs of polypeptide chains, each pair having one “light” (about 25 KD) and one “heavy” chain (about 50-70 KD). The N-terminus of each chain may define a variable region of about 100 to 110 or more amino acids primarily responsible for antigen recognition. The terms “light chain variable region” (VL) and “heavy chain variable region” (VH), as used herein, generally refer to these regions of the light and heavy chains respectively. Antibodies may exist as intact immunoglobulins or as a number of well characterized fragments produced by digestion with various peptidases or expressed de novo. Thus, for example, pepsin may digest an antibody below the disulfide linkages in the hinge region to produce F(ab)′2 (a dimer of Fab which itself is a light chain joined to VH-CH1 by a disulfide bond). The F(ab)′2 may be reduced under mild conditions to break the disulfide linkage in the hinge region thereby converting the (Fab′)2 dimer into a Fab′ monomer. The Fab′ monomer is essentially a Fab with part of the hinge region (see, Fundamental Immunology, W. E. Paul, ed., Raven Press, N.Y. (1993), for a more detailed description of other antibody fragments). While various antibody fragments are defined in terms of the digestion of an intact antibody, one of ordinary skill in the art will appreciate that such Fab&#39; fragments may be synthesized de novo either chemically or by utilizing recombinant DNA methodology. Thus, the term antibody, as used herein, may also include antibody fragments either produced by the modification of whole antibodies or synthesized de novo using recombinant DNA methodologies, including, but are not limited to, Fab′2, IgG, IgM, IgA, IgE, scFv, dAb, nanobodies, unibodies, and diabodies. In some embodiments, the antibodies include, but are not limited to Fab′2, IgG, IgM, IgA, IgE, and single chain antibodies, for example, single chain Fv (scFv) antibodies in which a variable heavy and a variable light chain are joined together (directly or through a peptide linker) to form a continuous polypeptide. 
     The term “antigen-binding site” or “binding portion,” as used herein, generally refers to a part of an antibody that participates in antigen binding. An antigen binding site may be formed by amino acid residues of the N-terminal variable (“V”) regions of a heavy (“H”) chain and/or a light (“L”) chain. Three highly divergent stretches within the V regions of the heavy and light chains are referred to as “hypervariable regions” which are interposed between more conserved flanking stretches known as “framework regions” or “FRs”. Thus, the term “FR,” as used herein, generally refers to amino acid sequences that are naturally found between and adjacent to hypervariable regions in immunoglobulins. In an antibody molecule, the three hypervariable regions of a light chain and the three hypervariable regions of a heavy chain are disposed relative to each other in three-dimensional space to form an antigen binding “surface”. This surface may mediate recognition and binding of the target antigen. The three hypervariable regions of each of the heavy and light chains are referred to as “complementarity determining regions” or “CDRs” and are characterized, for example by Kabat et al.  Sequences of proteins of immunological interest,  4 th  ed. U.S. Dept. Health and Human Services, Public Health Services, Bethesda, Md. (1987). 
     The term “host cell” as used herein, generally includes an individual cell, a cell line or cell culture which can be or has been a recipient for the subject plasmids or vectors, comprise the polynucleotide of the present disclosure, or express the proteinaceous heterodimer (e.g. heterodimer protein) of the present disclosure. Host cells may include progeny of a single host cell. The progeny may not necessarily be completely identical (in morphology or in genomic of total DNA complement) to the original parent cell due to natural, accidental, or deliberate mutation. A host cell may include cells transfected in vitro with a vector of the present disclosure. A host cell may be a bacterial cell (e.g.,  E. coli ), a yeast cell or other eukaryotic cells, e.g., a COS cell, a Chinese hamster ovary (CHO) cell, a HeLa cell, a HEK293 cell, a COS-1 cell, an NSO cell, or a myeloma cell. In some embodiments, a host cell is a mammalian cell. In some embodiments, the mammalian cell is a HEK293 cell. 
     The term “vector” as used herein, generally refers to a nucleic acid molecule capable of self-replicating in an appropriate host, which transfers an inserted nucleic acid molecule into and/or between host cells. The term may include vectors that function primarily for insertion of DNA or RNA into a cell, replication of vectors that function primarily for the replication of DNA or RNA, and expression vectors that function for transcription and/or translation of the DNA or RNA. Also included are vectors that provide more than one of the above functions. An “expression vector” is a polynucleotide which, when introduced into an appropriate host cell, can be transcribed and translated into a polypeptide(s). An “expression system” usually connotes a suitable host cell comprising an expression vector that can function to yield a desired expression product. 
     The term “effective amount” or “therapeutically effective amount” refers to an amount of a composition (e.g., a proteinaceous heterodimer described herein) that is sufficient to effect the intended application, including but not limited to disease treatment. The therapeutically effective amount may vary depending upon the intended application (e.g., in vitro or in vivo), or the subject and disease condition being treated, e.g., the weight and age of the subject, the severity of the disease condition, the manner of administration and the like, which can readily be determined by one of ordinary skill in the art. The term may also apply to a dose that will induce a particular response in target cells, e.g. target gene induction, proliferation, and/or apoptosis. The specific dose will vary depending on the particular compounds chosen, the dosing regimen to be followed, whether it is administered in combination with other compounds, timing of administration, the tissue to which it is administered, and the physical delivery system in which it is carried. 
     The terms “treatment” or “treating” or “palliating” or “ameliorating” is used interchangeably herein, and refer to an approach for obtaining beneficial or desired results including but not limited to a therapeutic benefit and/or a prophylactic benefit. As used herein, therapeutic benefit generally refers to eradication or reduced severity of the underlying disorder being treated. Also, a therapeutic benefit is achieved with the eradication, reduced severity or reduced incidence of one or more of the physiological symptoms associated with the underlying disorder such that an improvement is observed in the subject, notwithstanding that the subject may still be afflicted with the underlying disorder. For prophylactic benefit, the compositions may be administered to a subject at risk of developing a particular disease, or to a subject reporting one or more of the physiological symptoms of a disease, even though a diagnosis of this disease may not have been made. 
     The term “therapeutic effect” as used herein, generally encompasses a therapeutic benefit and/or a prophylactic benefit as described above. A prophylactic effect includes delaying or eliminating the appearance of a disease or condition, delaying or eliminating the onset of symptoms of a disease or condition, slowing, halting, or reversing the progression of a disease or condition, or any combination thereof. 
     The term “agent” or “biologically active agent” as used herein, generally refers to a biological, pharmaceutical, or chemical compound or other moieties. Non-limiting examples include a simple or complex organic or inorganic molecule, a peptide, a protein, an oligonucleotide, an antibody, an antibody derivative, antibody fragment, a vitamin derivative, a carbohydrate, a toxin, or a chemotherapeutic compound. Various compounds can be synthesized, for example, small molecules and oligomers (e.g., oligopeptides and oligonucleotides), and synthetic organic compounds based on various core structures. In addition, various natural sources can provide compounds for screening, such as plant or animal extracts, and the like. 
     The term “cell proliferation” as used herein, generally refers to a phenomenon by which the cell number has changed as a result of division. For example, cell proliferation may result in an increase in number of cells. This term also encompasses cell growth by which the cell morphology has changed (e.g., increased in size) consistent with a proliferative signal. 
     The term “in vivo” as used herein, generally refers to an event that takes place in a subject&#39;s body. 
     The term “in vitro” as used herein, generally refers to an event that takes places outside of a subject&#39;s body. For example, an in vitro assay encompasses any assay conducted outside of a subject. In vitro assays encompass cell-based assays in which dead or living cells are employed. In vitro assays also encompass a cell-free assay in which no intact cells are employed. 
     The term “interleukin” as used herein, generally refers to a secreted protein or a signaling molecule capable of promoting the development and differentiation of T and/or B lymphocytes and/or hematopoietic cells. An interleukin may be synthesized by helper CD4 T lymphocytes, as well as through monocytes, macrophages, and endothelial cells. As used herein, an interleukin (IL) may include IL-1, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-11, IL-12, IL-13, IL-14, IL-15, IL-16, IL-17, IL-18, IL-19, IL-20, IL-21, IL-22, IL-23, IL-24, IL-25, IL-26, IL-27, IL-28, IL-29, IL-30, IL-31, IL-32, IL-33, IL-34, IL-35, and/or IL-36. As used herein, the term “interleukin” may include full length interleukins, or a fragment (e.g., a truncated form) or variant thereof substantially maintaining the biological activities of a corresponding wild-type interleukin (e.g., having a biological activity that is at least 80%, at least 90%, at least 95%, at least 98%, at least 99%, or even at least 100% of the biological activity of a corresponding wild-type interleukin). An interleukin, as used herein, may be from any mammalian species. In some embodiments, the interleukin is from a species selected from the group consisting of human, horse, cattle, murine, pig, rabbit, cat, dog, rat, goat, sheep, and non-human primate. In some embodiments, the interleukin can be in a mutated form, for example, with increased or decreased affinity to its receptors. In specific embodiments, the interleukin can be a super IL-2 (also known as sIL2, see  Nature  484, 529-533, 26 Apr. 2012), which may be obtained by modifying IL-2 to increase its binding affinity for IL-2R13. Mutations in sIL-2 are principally in the core of the cytokine, and molecular dynamics simulations indicated that the evolved mutations stabilized IL-2, reducing the flexibility of a helix in the IL-2R13 binding site, into an optimized receptor-binding conformation resembling that when bound to CD25. Compared to IL-2, sIL-2 induced superior expansion of cytotoxic T cells, leading to improved anti-tumor responses in vivo, and elicited proportionally less expansion of T regulatory cells and reduced pulmonary edema. 
     The term “subject” as used herein, generally refers to a human or non-human animal, including, but not limited to, a cat, dog, horse, pig, cow, sheep, goat, rabbit, mouse, rat, or monkey. 
     The term “inhibition of growth and/or proliferation,” when used with cancer cells, generally refers to decrease in the growth rate and/or proliferation rate of a cancer cell. For example, this may include death of a cancer cell (e.g. via apoptosis). In some embodiments, this term may also refer to inhibiting the growth and/or proliferation of a solid tumor and/or inducing tumor size reduction or elimination of the tumor. 
     The term “a cancer cell surface marker” or “a cancer cell associated marker,” as used herein, generally refers to biomolecules such as proteins, carbohydrates, glycoproteins, and the like that are exclusively or preferentially or differentially expressed on a cancer cell and/or are found to be associated with a cancer cell and thereby provide targets preferential or specific to the cancer. In some embodiments, the preferential expression can be preferential expression as compared to any other cell in the organism, or preferential expression within a particular area of the organism (e.g. within a particular organ or tissue). 
     The term “monomeric member” as used herein, generally refers to a polypeptide, subunit, or moiety, which is present as a monomer, and is a component/subunit of the proteinaceous heterodimer. 
     The term “Fc subunit” as used herein, generally refers to the carboxyl terminal portion of an immunoglobulin heavy chain constant region, or an analog or portion thereof capable of binding an Fc receptor. As is known, each immunoglobulin heavy chain constant region comprises four or five domains. The domains are named sequentially as follows: CH1-hinge-CH2-CH3(-CH4). CH4 is present in IgM, which has no hinge region. The immunoglobulin heavy chain constant region useful in the present disclosure may comprise an immunoglobulin hinge region, and may also include a CH3 domain. For example, the immunoglobulin heavy chain constant region may comprise an immunoglobulin hinge region, a CH2 domain and a CH3 domain. In some embodiments, the Fc subunit according to the present disclosure consists of the hinge-CH2-CH3 domain. 
     The term “complexed with” or “complexation” as used herein, generally refers to the association (e.g., binding) of one member/subunit with another member/subunit of a molecule (e.g., a proteinaceous heterodimer). For example, a first Fc subunit may be complexed with a second subunit to form a dimer. 
     The term “binding specificity” as used herein, generally refers to the ability to specifically bind (e.g., immunoreact with) a given target (while not binding or substantially not binding a non-target). A targeting moiety of the present disclosure may be monospecific and contain one or more binding sites which specifically bind a target or may be multi specific (e.g., bispecific or trispecific) and contain two or more binding sites which specifically bind the same or different targets. 
     The term “associates with” or “associated with” as used herein, generally refers to that one entity is in physical association or contact with another. For example, a first monomeric member of the proteinaceous heterodimer may “associate with” a second monomeric member covalently or non-covalently. In some embodiments, a first monomeric member of the proteinaceous heterodimer associates with a second monomeric member via an interface, and the interface is formed by amino acid residues (i.e., interface residues) from the first monomeric member and the second monomeric member, respectively. 
     The term “modification” as used herein, generally refers to any manipulation of the peptide backbone (e.g. amino acid sequence) or any post-translational modifications (e.g. glycosylation) of a polypeptide. For example, a modification is in comparison to the sequence of a corresponding wildtype polypeptide. A modification may be a substitution, an addition, and/or a deletion of one or more amino acids (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more). 
     The term “knob-and-hole modification” as used herein, generally refers to introducing a modification at the interface of a polypeptide to form a bulge (knob modification) and introducing a modification at a corresponding position of another polypeptide to form a cavity (hole-modification), and the size of the bulge is the same or similar to that of the cavity. For example, the knob-and-hole modification enables the formation of a heterodimer, while inhibiting the formation of homodimers. See the reference of U.S. Pat. Nos. 5,731,168; 7,695,936; Ridgway et al., Prot Eng 9, 617-621 (1996) and Carter, J Immunol Meth 248, 7-15 (2001). Accordingly, the term “knob modification” as used herein, generally refers to a modification at the interface of a polypeptide to replace an amino acid having a smaller side chain (e.g., alanine or threonine) with an amino acid having a larger side chain (e.g., tyrosine or tryptophan) to form a bulge. The term “hole modification” as used herein, generally refers to a modification at a corresponding position of another polypeptide to replace an amino acid having a larger side chain (e.g., tyrosine or tryptophan) with an amino acid having a smaller side chain (e.g., alanine or threonine) to form a cavity. The knob modification and the hole modification can be made by altering the nucleic acid encoding the polypeptides, e.g. by site-specific mutagenesis, or by peptide synthesis. In a specific embodiment, a knob modification comprises the amino acid substitutions Y349C and T366W in one of the two subunits of the Fc region, and the hole modification comprises the amino acid substitutions D356C, T366S, L368A and Y407V in the other one of the two subunits of the Fc region. 
     The term “HEK293 cell” as used herein, generally refers to clonal isolates derived from transformed human embryonal kidney (HEK) cells. The HEK293 strain is a variant of the 293 cell line that demonstrates better adherence in monolayer culture and ease of use for plaque assays and other anchorage dependent applications. They have been adapted to suspension culture in serum-free media, e.g., 293 SFM II. 
     The term “CHO cell” as used herein, generally refers to Chinese hamster ovary cells, which are non-secretory, immortal fibroblasts. The CHO cells rarely secrete CHO endogenous protein, so is favorable to the separation and purification for a target protein. 
     The term “COS-1 cell” as used herein, generally refers to fibroblast-like cell lines derived from monkey kidney tissue. COS cells are obtained by immortalizing CV-1 cells with a version of the SV40 virus that can produce large T antigen but has a defect in genomic replication. One form of COS cell lines commonly used is COS-1. 
     The term “NSO cell” as used herein, generally refers to a model cell line derived from the non-secreting murine myeloma. The cell line is a cholesterol-dependent cell line that was generated from a subline of NSI/1. 
     The term “fusion protein” as used herein, generally refers to a polypeptide that comprises, or alternatively consists of, an amino acid sequence of a polypeptide fused directly or indirectly (e.g., via a linker) to an amino acid sequence of a heterologous polypeptide (i.e., a polypeptide unrelated to the former polypeptide or the domain thereof). 
     The term “C-terminus” as used herein, generally refers to the carboxy terminus of a polypeptide. 
     The term “N-terminus” as used herein, generally refers to the amino terminus of a polypeptide. 
     The term “immunoglobulin” as used herein, generally refers to a protein consisting of one or more polypeptides substantially encoded by immunoglobulin genes. The recognized immunoglobulin genes include the κ, λ, α, γ (IgG1, IgG2, IgG3, IgG4), δ, ε and μ constant region genes, as well as the myriad immunoglobulin variable region genes. One form of immunoglobulin constitutes the basic structural unit of an antibody. This form is a tetramer and consists of two identical pairs of immunoglobulin chains, each pair having one light and one heavy chain. In each pair, the light and heavy chain variable regions are together responsible for binding to an antigen, and the constant regions are responsible for the antibody effector functions. In addition to antibodies, immunoglobulins may exist in a variety of other forms including, for example, Fv, Fab, Fab′ and (Fab′)2. 
     The term “fused in frame” or “in frame fused” as used herein, generally refers to the joining of two or more open reading frames (ORFs) to form a continuous longer ORF, in a manner that maintains the correct reading frame of the original ORFs. 
     The term “linker” as used herein, generally refers to a synthetic amino acid sequence that connects or links two polypeptide sequences, e.g., that links two polypeptide domains. A linker may connect two amino acid sequences via peptide bonds. In some embodiments, a linker of the present disclosure connects an immunoregulator to the second Fc region in a linear sequence. 
     The term “located N-terminal to” as used herein, generally refers to locating at a position N-terminal to another molecule (e.g., another polypeptide). For example, according to the present disclosure, two or more immunoregulators may be located N-terminal to the second Fc region. 
     The term “amino acid substitution” as used herein, generally refers to that one amino acid at a specific position of a polypeptide is replaced by another amino acid. 
     The term “EU index of the KABAT number” as used herein, generally refers to the index of the EU number corresponding to the amino acid sequence according to Kabat et al. (1971) Ann. NY Acad, Sci. 190: 382-391 and Kabat, E. A., et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91-3242. 
     The term “isolated polynucleotide” as used herein, generally refers to a polymeric form of nucleotides of any length, either deoxyribonucleotides or ribonucleotides, or analogs thereof, isolated from its native environment, or that is artificially synthesized. 
     The term “protein mixture” as used herein, generally refers to a mixture of two or more types of proteins. 
     The term “homodimer” as used herein, generally refers to a molecule formed by two identical monomers (e.g., two identical members or subunits). The two monomers may aggregate, complex or associate with each other via covalent and/or non-covalent interactions. For example, the two monomers of a proteinaceous homodimer may associate with each other via interactions between interface amino acid residues from each of said two monomers. 
     The term “substantially comprises no” as used herein, generally refers that a composition (e.g., a mixture) comprises little or almost none of a substance. For example, said substance is present with a percentage of e.g., less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.5%, less than 0.1%, or less than 0.01%. 
     The term “pharmaceutically acceptable excipient” as used herein, generally refers to any and all solvents, dispersion media, coatings, isotonic and absorption delaying agents, etc., that are compatible with pharmaceutical administration. 
     The term “enrichment” as used herein, generally refers to an increase of the number and/or concentration of a target component in a mixture or a population. 
     Proteinaceous Heterodimers, Protein Mixtures, Isolated Polynucleotides, Vectors and Host Cells 
     In one aspect, the present disclosure provides a proteinaceous heterodimer. The proteinaceous heterodimer may comprise a first monomeric member and a second monomeric member different from the first monomeric member. The first monomeric member may comprise a first Fc subunit. The second monomeric member may comprise a second Fc subunit. The first monomeric member may associate with the second monomeric member to form the heterodimer through complexation of the first Fc subunit with the second Fc subunit. 
     In some embodiments, the amino acid sequence of the first monomeric member is different from the amino acid sequence of the second monomeric member. 
     The proteinaceous heterodimer may further comprise one or more interleukins. The one or more interleukins may be fused (e.g., in frame fused) to the first Fc subunit and/or the second Fc subunit. For example, the one or more interleukins may independently be fused (e.g., in frame fused) to the first Fc subunit and/or the second Fc subunit in frame. In some embodiments, one or more interleukins are fused (e.g., in frame fused) only to the first Fc subunit. In some embodiments, one or more interleukins are fused (e.g., in frame fused) only to the second Fc subunit. In some embodiments, one or more interleukins are fused (e.g., in frame fused) to both the first and the second Fc subunit. 
     The one or more interleukins may be fused (e.g., in frame fused) to an amino-terminal amino acid and/or a carboxy-terminal amino acid of the first Fc subunit and/or the second Fc subunit. In some embodiments, one or more of the interleukins are fused (e.g., in frame) to an amino-terminal amino acid of the first Fc subunit. In some embodiments, one or more of the interleukins are fused (e.g., in frame) to an amino-terminal amino acid of the second Fc subunit. In some embodiments, one or more of the interleukins are fused (e.g., in frame) to both an amino-terminal amino acid of the first Fc subunit and an amino-terminal amino acid of the second Fc subunit. 
     In the proteinaceous heterodimer, at least one of the one or more interleukins may be interleukin 10. 
     The one or more interleukins may be fused (e.g., in frame) to the first Fc subunit and/or the second Fc subunit directly or indirectly. For example, the one or more interleukins may be fused (e.g., in frame) to the first Fc subunit and/or the second Fc subunit via a linker, such as a peptide linker. The linker may be a synthetic amino acid sequence that connects or links two polypeptide sequences, e.g., via peptide bonds. In some embodiments, a linker is a peptide comprising e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 or more amino acids. For example, the linker may comprise 1-10 amino acids (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more amino acids), 1-15 amino acids (e.g., 1-11, 12, 13, 14, 15 amino acids), 1-20 amino acids, 1-30 amino acids or more. In some embodiments, the linker comprises an amino acid sequence as set forth in SEQ ID NO: 37. 
     In some embodiments, the proteinaceous heterodimer comprises two or more interleukins. The two or more interleukins may be the same or may be different. In some embodiments, the two or more interleukins are the same. In some embodiments, the two or more interleukins are interleukin 10. 
     The two or more interleukins may form one or more interleukin dimers, with each interleukin dimer comprising two interleukins fused (e.g., in frame) to each other. Each interleukin dimer may comprise two identical or two different interleukins. The interleukins may be fused (e.g., in frame) together directly or indirectly. In some embodiments, the one or more interleukin dimers comprises at least one interleukin 10 dimer, with the interleukin 10 dimer comprising two interleukin 10. 
     Two or more interleukins (e.g., two interleukins of each interleukin dimer) may be fused (e.g., in frame) together through a linker (such as a peptide linker). The linker may be a synthetic amino acid sequence that connects or links two polypeptide sequences, e.g., via peptide bonds. In some embodiments, a linker is a peptide comprising 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 or more amino acids. For example, the linker may comprise 1-10 amino acids (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more amino acids), 1-15 amino acids (e.g., 1-11, 12, 13, 14, 15 amino acids), 1-20 amino acids, 1-30 amino acids or more. In some embodiments, the linker comprises an amino acid sequence as set forth in SEQ ID NO: 37. In some embodiments, the linker is resistant to proteolysis or substantially resistant to proteolysis. 
     In some cases, more than two interleukins may be comprised by the proteinaceous heterodimer. The more than two interleukins may form two or more interleukin dimers. For example, the two or more interleukin dimers may comprise at least one interleukin 10 dimer, and the interleukin 10 dimer comprises two interleukin 10. In some embodiments, the proteinaceous heterodimer comprises two or more interleukin 10 dimers. 
     The fused two or more interleukins (e.g., interleukin dimer) may further be fused (e.g., in frame) to an amino-terminal amino acid and/or a carboxy-terminal amino acid of the first Fc subunit and/or the second Fc subunit. In some embodiments, the fused two or more interleukins (e.g., interleukin dimer) are further fused to an amino-terminal amino acid of the first Fc subunit and/or the second Fc subunit. In some embodiments, the fused two or more interleukins (e.g., interleukin dimer) are further fused to an amino-terminal amino acid of only the first Fc subunit. In some embodiments, the fused two or more interleukins (e.g., interleukin dimer) are further fused to an amino-terminal amino acid of only the second Fc subunit. In some embodiments, the fused two or more interleukins (e.g., interleukin dimer) are further fused to both an amino-terminal amino acid of the first Fc subunit and an amino-terminal amino acid of the second Fc subunit. 
     When there are two or more interleukin dimers, each interleukin dimer may independently be fused to an amino-terminal amino acid and/or a carboxy-terminal amino acid of the first Fc subunit and/or the second Fc subunit. For example, two or more fused interleukins (e.g., interleukin 10) may be further fused (e.g., in frame) to the first Fc subunit (e.g., to an amino-terminal amino acid thereof) and two or more fused interleukins (e.g., interleukin 10) may be further fused (e.g., in frame) to the second Fc subunit (e.g., to an amino-terminal amino acid thereof). 
     The fused two or more interleukins (e.g., interleukin dimer) may be fused to the first Fc subunit and/or the second Fc subunit directly or indirectly. For example, the fused two or more interleukins (e.g., interleukin dimer) may be fused to the first Fc subunit and/or the second Fc subunit via a linker (such as a peptide linker). The linker may be a synthetic amino acid sequence that connects or links two polypeptide sequences, e.g., via peptide bonds. In some embodiments, a linker is a peptide comprising 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 or more amino acids. For example, the linker may comprise 1-10 amino acids (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more amino acids), 1-15 amino acids (e.g., 1-11, 12, 13, 14, 15 amino acids), 1-20 amino acids, 1-30 amino acids or more. In some embodiments, the linker comprises an amino acid sequence as set forth in SEQ ID NO: 37. In some embodiments, the linker is resistant to proteolysis or substantially resistant to proteolysis. 
     In some embodiments, at least one of the one or more interleukins is fused (e.g., in frame) to the second Fc subunit. For example, the at least one of the one or more interleukins may be fused to an amino-terminal amino acid of the second Fc subunit. 
     In some embodiments, in the second monomeric member, at least two of the one or more interleukins are fused (e.g., in frame) to each other to form an interleukin dimer, and the interleukin dimer is further fused (in frame) to the amino-terminal amino acid of the second Fc subunit. 
     In some embodiments, the first monomeric member does not comprise any interleukin. 
     In some embodiments, the first monomeric member consists of the first Fc subunit. 
     In some embodiments, at least one of the one or more interleukins is fused (e.g., in frame) to the first Fc subunit. 
     In some embodiments, at least one of the one or more interleukins is fused (e.g., in frame) to an amino-terminal amino acid of the first Fc subunit. 
     In some embodiments, in the first monomeric member, at least two of the one or more interleukins are fused (e.g., in frame) to each other to form an interleukin dimer, and the interleukin dimer is further fused (e.g., in frame) to the amino-terminal amino acid of the first Fc subunit. 
     In some embodiments, the second monomeric member does not comprise any interleukin. 
     In some embodiments, the second monomeric member consists of the second Fc subunit. 
     In some embodiments, the first monomeric member does not comprise any interleukin, or the first monomeric member consists of the first Fc subunit, and at least one of the one or more interleukins is fused (e.g., in frame) to the second Fc subunit. In some cases, in the second monomeric member, at least two of the one or more interleukins are fused (e.g., in frame) to each other to form an interleukin dimer, and the interleukin dimer is further fused (in frame) to the amino-terminal amino acid of the second Fc subunit. 
     In some embodiments, the second monomeric member does not comprise any interleukin, or the second monomeric member consists of the second Fe subunit, and at least one of the one or more interleukins is fused (e.g., in frame) to the first Fc subunit. In some cases, in the first monomeric member, at least two of the one or more interleukins are fused (e.g., in frame) to each other to form an interleukin dimer, and the interleukin dimer is further fused (in frame) to the amino-terminal amino acid of the first Fc subunit. 
     In some embodiments, the first monomeric member comprises one or more interleukins fused to the first Fc subunit, and the second monomeric member comprises one or more interleukins fused to the second Fc subunit. 
     In some embodiments, the first monomeric member comprises one or more interleukin dimers fused to the first Fc subunit, and the second monomeric member comprises one or more interleukin dimers fused to the second Fc subunit. Each interleukin dimer may comprise two identical interleukins fused (e.g. in frame) to each other directly or indirectly (e.g., via a linker, such as a peptide linker). 
     The proteinaceous heterodimer of the present application does not comprise any antibody heavy chain variable region or any antibody light chain variable region exhibiting binding specificity to a tumor antigen. In some embodiments, the proteinaceous heterodimer of the present application does not comprise any antibody or any part (e.g., an antigen-binding fragment) thereof exhibiting binding specificity to a tumor antigen. 
     In some embodiments, the proteinaceous heterodimer of the present application does not comprise any antibody heavy chain variable region or any antibody light chain variable region. 
     In some embodiments, the proteinaceous heterodimer of the present application does not comprise any antibody or antigen-binding fragments thereof. 
     In some embodiments, the proteinaceous heterodimer of the present application does not comprise any targeting moiety exhibiting binding specificity to any tumor antigen. For example, in some cases, the proteinaceous heterodimer of the present application does not comprise any antibody or antigen-binding fragments thereof capable of specifically binding to a tumor antigen. 
     In some embodiments, the first Fc subunit and/or the second Fc subunit is independently from an IgG molecule. The IgG may be selected from the group consisting of IgG1, IgG2, IgG3 and IgG4. For example, the IgG may be a human IgG1. 
     In some embodiments, the first Fc subunit is different from the second Fc subunit, and the first and/or second Fc subunit comprises a modification promoting heterodimerization between the first Fc subunit and the second Fc subunit. 
     The first Fc subunit may comprise a first modification, and the second Fc subunit may comprise a second modification. 
     In some embodiments, the first modification comprises an amino acid substitution at position T366, and an amino acid substitution at one or more positions selected from the group consisting of: Y349, F405, K409, D399, K360, Q347, K392 and 5354, wherein the position of the amino acid is determined according to the EU index of the KABAT number. For example, the amino acid substitution comprised by the first modification may be selected from the group consisting of: Y349C, Y349D, D399S, F405K, K360E, K409A, K409E, Q347E, Q347R, S354D, K392D and T366W. 
     In some embodiments, the first modification comprises 2-5 amino acid substitutions. 
     In some embodiments, the first modification comprises an amino acid substitution at a group of positions selected from any of the following groups: 1) Y349 and T366; 2) Y349, T366 and F405; 3) Y349, T366 and K409; 4) Y349, T366, F405, K360 and Q347; 5) Y349, T366, F405 and Q347; 6) Y349, T366, K409, K360 and Q347; 7) Y349, T366, K409 and Q347; 8) T366, K409 and K392; 9) T366 and K409; 10) T366, K409, Y349 and S354; 11) T366 and F405; 12) T366, F405 and D399; and 13) T366, F405, Y349 and S354; wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     In some embodiments, the first modification comprises a group of amino acid substitutions selected from any of the following groups: 1) Y349C and T366W; 2) Y349C, T366W and F405K; 3) Y349C, T366W and K409E; 4) Y349C, T366W and K409A; 5) Y349C, T366W, F405K, K360E and Q347E; 6) Y349C, T366W, F405K and Q347R; 7) Y349C, T366W, K409A, K360E and Q347E; 8) Y349C, T366W, K409A and Q347R; 9) T366W, K409A and K392D; 10) T366W and K409A; 11) T366W, K409A and Y349D; 12) T366W, K409A, Y349D and S354D; 13) T366W and F405K; 14) T366W, F405K and D399S; 15) T366W, F405K and Y349D; and 16) T366W, F405K, Y349D and S354D; wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     In some embodiments, the second modification comprises amino acid substitutions at positions T366, L368 and Y407, as well as an amino acid substitution at one or more positions selected from the group consisting of D356, D399, E357, F405, K360, K392, K409 and Q347, wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     In some embodiments, the amino acid substitution comprised by the second modification is selected from the group consisting of D356C, D399S, E357A, F405K, K360E, K392D, K409A, L368A, L368G, Q347E, Q347R, T366S, Y407A and Y407V. 
     In some embodiments, the second modification comprises an amino acid substitution at 4-6 positions. 
     In some embodiments, the second modification comprises an amino acid substitution at a group of positions selected from any of the following groups: 1) D356, T366, L368, Y407 and F405; 2) D356, T366, L368 and Y407; 3) D356, T366, L368, Y407 and Q347; 4) D356, T366, L368, Y407, K360 and Q347; 5) D356, T366, L368, Y407, F405 and Q347; 6) D356, T366, L368, Y407, F405, K360 and Q347; 7) T366, L368, Y407, D399 and F405; 8) T366, L368, Y407 and F405; 9) T366, L368, Y407, F405 and E357; 10) T366, L368, Y407 and K409; 11) T366, L368, Y407, K409 and K392; and 12) T366, L368, Y407, K409 and E357; wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     In some embodiments, the second modification comprises a group of amino acid substitutions selected from any of the following groups: 1) D356C, T366S, L368A, Y407V and F405K; 2) D356C, T366S, L368A and Y407V; 3) D356C, T366S, L368A, Y407V and Q347R; 4) D356C, T366S, L368A, Y407V, K360E and Q347E; 5) D356C, T366S, L368A, Y407V, F405K and Q347R; 6) D356C, T366S, L368A, Y407V, F405K, K360E and Q347E; 7) T366S, L368A, Y407V, D399S and F405K; 8) T366S, L368G, Y407A and F405K; 9) T366S, L368A, Y407V, F405K and E357A; 10) T366S, L368A, Y407V and K409A; 11) T366S, L368A, Y407V, K409A and K392D; 12) T366S, L368G, Y407A and K409A; 13) T366S, L368A, Y407V, K409A and E357A; wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     In some embodiments, the first Fc subunit comprises the first modification, the second Fc subunit comprises the second modification, and the first modification and the second modification comprise an amino acid substitution at a group of positions selected from any of the following groups: 1) the first modification: Y349 and T366; and the second modification: D356, T366, L368, Y407 and F405; 2) the first modification: Y349, T366 and F405; and the second modification: D356, T366, L368 and Y407; 3) the first modification: Y349, T366 and K409; and the second modification: D356, T366, L368, Y407 and F405; 4) the first modification: Y349, T366, F405, K360 and Q347; and the second modification: D356, T366, L368, Y407 and Q347; 5) the first modification: Y349, T366, F405 and Q347; and the second modification: D356, T366, L368, Y407, K360 and Q347; 6) the first modification: Y349, T366, K409, K360 and Q347; and the second modification: D356, T366, L368, Y407, F405 and Q347; 7) the first modification: Y349, T366, K409 and Q347; and the second modification: D356, T366, L368, Y407, F405, K360 and Q347; 8) the first modification: T366, K409 and K392; and the second modification: T366, L368, Y407, D399 and F405; 9) the first modification: T366 and K409; and the second modification: T366, L368, Y407 and F405; 10) the first modification: T366, K409 and Y349; and the second modification: T366, L368, Y407, F405 and E357; 11) the first modification: T366, K409, Y349 and 5354; and the second modification: T366, L368, Y407, F405 and E357; 12) the first modification: T366 and F405; and the second modification: T366, L368, Y407 and K409; 13) the first modification: T366, F405 and D399; and the second modification: T366, L368, Y407, K409 and K392; 14) the first modification: T366, F405 and Y349; and the second modification: T366, L368, Y407, K409 and E357; 15) the first modification: T366, F405, Y349 and S354; and the second modification: T366, L368, Y407, K409 and E357; wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     In some embodiments, the first Fc subunit comprises the first modification, the second Fc subunit comprises the second modification, wherein the first modification and the second modification comprise a group of amino acid substitutions selected from any of the following groups: 1) the first modification: Y349C and T366W; and the second modification: D356C, T366S, L368A, Y407V and F405K; 2) the first modification: Y349C, T366W and F405K; and the second modification: D356C, T366S, L368A and Y407V; 3) the first modification: Y349C, T366W and K409E; and the second modification: D356C, T366S, L368A, Y407V and F405K; 4) the first modification: Y349C, T366W and K409A; and the second modification: D356C, T366S, L368A, Y407V and F405K; 5) the first modification: Y349C, T366W, F405K, K360E and Q347E; and the second modification: D356C, T366S, L368A, Y407V and Q347R; 6) the first modification: Y349C, T366W, F405K and Q347R; and the second modification: D356C, T366S, L368A, Y407V, K360E and Q347E; 7) the first modification: Y349C, T366W, K409A, K360E and Q347E; and the second modification: D356C, T366S, L368A, Y407V, F405K and Q347R; 8) the first modification: Y349C, T366W, K409A and Q347R; and the second modification: D356C, T366S, L368A, Y407V, F405K, K360E and Q347E; 9) the first modification: T366W, K409A and K392D; and the second modification: T366S, L368A, Y407V, D399S and F405K; 10) the first modification: T366W and K409A; and the second modification: T366S, L368G, Y407A and F405K; 11) the first modification: T366W, K409A and Y349D; and the second modification: T366S, L368A, Y407V, F405K and E357A; 12) the first modification: T366W, K409A, Y349D and S354D; and the second modification: T366S, L368A, Y407V, F405K and E357A; 13) the first modification: T366W and F405K; and the second modification: T366S, L368A, Y407V and K409A; 14) the first modification: T366W, F405K and D399S; and the second modification: T366S, L368A, Y407V, K409A and K392D; 15) the first modification: T366W and F405K; and the second modification: T366S, L368G, Y407A and K409A; 16) the first modification: T366W, F405K and Y349D; and the second modification: T366S, L368A, Y407V, K409A and E357A; 17) the first modification: T366W, F405K, Y349D and S354D; and the second modification: T366S, L368A, Y407V, K409A and E357A; wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     In some embodiments, the first Fc subunit comprises the first modification, the second Fc subunit comprises the second modification, the first modification comprises the amino acid substitutions T366W and K409A, and the second modification comprises the amino acid substitutions T366S, L368G, Y407A and F405K, wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     In some embodiments, the first and second Fc subunit comprises modifications promoting heterodimerization between the first Fc subunit and the second Fc subunit, such as a knob-and-hole modification. For example, the first Fc subunit may comprise a knob modification and the second Fc subunit may comprise a hole modification. In some cases, the first Fc subunit may comprise a hole modification and the second Fc subunit may comprise a knob modification. 
     The knob modification may comprise the amino acid substitutions Y349C and T366W, and the hole modification may comprise the amino acid substitutions D356C, T366S, L368A and Y407V, wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     In some embodiments, the amino acid sequence of the first Fc subunit is selected from the group consisting of: SEQ ID NO:1, 3, 5 ,6, 7, 9, 11, 13, 15, 17, 19, 21, 22, 24, 27, 29 and 30. 
     In some embodiments, the amino acid sequence of the interleukins comprised by the proteinaceous heterodimer is selected from the group consisting of: SEQ ID NO: 49 and 51. 
     In some embodiments, the amino acid sequence of the second Fc subunit is selected from the group consisting of: SEQ ID NO:2, 4, 8, 10, 12, 14, 16, 18, 20, 23, 25, 26, 28 and 30. 
     In one respect, the present disclosure provides an isolated nucleic acid or isolated nucleic acids encoding the proteinaceous heterodimer according to the present disclosure. In some embodiments, an isolated nucleic acid encodes a monomeric member (e.g., the first monomeric member or the second monomeric member) or a fragment of the proteinaceous heterodimer according to the present disclosure. 
     The nucleic acid may be synthesized using recombinant techniques well known in the art. For example, the nucleic acid may be synthesized using an automated DNA synthesizer. 
     Standard recombinant DNA and molecular cloning techniques include those described by Sambrook, J., Fritsch, E. F. and Maniatis, T  Molecular Cloning: A Laboratory Manual; Cold Spring Harbor Laboratory Press : Cold Spring Harbor, (1989) (Maniatis) and by T. J. Silhavy, M L. Bennan, and L. W Enquist,  Experiments with Gene Fusions, Cold Spring Harbor Laboratory , Cold Spring Harbor, N.Y. (1984) and by Ausubel, F. M et al.,  Current Protocols in Molecular Biology , pub. by Greene Publishing Assoc. and Wiley-Interscience (1987). Briefly, the subject nucleic acids can be prepared from genomic DNA fragments, cDNAs, and RNAs, all of which can be extracted directly from a cell or recombinantly produced by various amplification processes including but not limited to PCR and RT-PCR. 
     Direct chemical synthesis of nucleic acids typically involves sequential addition of 3′-blocked and 5′-blocked nucleotide monomers to the terminal 5′-hydroxyl group of a growing nucleotide polymer chain, wherein each addition is effected by nucleophilic attack of the terminal 5′-hydroxyl group of the growing chain on the 3′-position of the added monomer, which is typically a phosphorus derivative, such as a phosphotriester, phosphoramidite, or the like. See for example, Matteuci et al.,  Tet. Lett.  521: 719 (1980); U.S. Pat. No. 4,500,707 to Caruthers et al.; and U.S. Pat. Nos. 5,436,327 and 5,700,637 to Southern et al. 
     In one respect, the present disclosure provides a vector or vectors comprising the isolated nucleic acid or isolated nucleic acids according to the present disclosure. 
     The vector may be any linear nucleic acids, plasmids, phagemids, cosmids, RNA vectors, viral vectors and the like. Non-limiting examples of a viral vector may include a retrovirus, an adenovirus and an adeno-associated virus. In some embodiments, the vector is an expression vector, e.g. a phage display vector. 
     An expression vector may be suitable for use in particular types of host cells and not others. For example, the expression vector can be introduced into the host organism, which is then monitored for viability and expression of any genes/polynucleotides contained in the vector. 
     The expression vector may also contain one or more selectable marker genes that, upon expression, confer one or more phenotypic traits useful for selecting or otherwise identifying host cells that carry the expression vector. Non-limiting examples of suitable selectable markers for eukaryotic cells include dihydrofolate reductase and neomycin resistance. 
     The subject vectors can be introduced into a host cell stably or transiently by a variety of established techniques. For example, one method involves a calcium chloride treatment wherein the expression vector is introduced via a calcium precipitate. Other salts, for example calcium phosphate, may also be used following a similar procedure. In addition, electroporation (that is, the application of current to increase the permeability of cells to nucleic acids) may be used. Other examples of transformation methods include microinjection, DEAE dextran mediated transformation, and heat shock in the presence of lithium acetate. Lipid complexes, liposomes, and dendrimers may also be employed to transfect the host cells. 
     Upon introduction of the heterologous sequence into a host cell, a variety of methods can be practiced to identify the host cells into which the subject vectors have been introduced. One exemplary selection method involves subculturing individual cells to form individual colonies, followed by testing for expression of the desired protein product. Another method entails selecting host cells containing the heterologous sequence based upon phenotypic traits conferred through the expression of selectable marker genes contained within the expression vector. 
     For example, the introduction of various heterologous sequences of the disclosure into a host cell can be confirmed by methods such as PCR, Southern blot or Northern blot hybridization. For example, nucleic acids can be prepared from the resultant host cells, and the specific sequences of interest can be amplified by PCR using primers specific for the sequences of interest. The amplified product is subjected to agarose gel electrophoresis, polyacrylamide gel electrophoresis or capillary electrophoresis, followed by staining with ethidium bromide, SYBR Green solution or the like, or detection of DNA with a UV detection. Alternatively, nucleic acid probes specific for the sequences of interest can be employed in a hybridization reaction. The expression of a specific gene sequence can be ascertained by detecting the corresponding mRNA via reverse-transcription coupled with PCR, Northern blot hybridization, or by immunoassays using antibodies reactive with the encoded gene product. Exemplary immunoassays include but are not limited to ELISA, radioimmunoassays, and sandwich immunoassays. 
     Furthermore, the introduction of various heterologous sequences of the disclosure into a host cell can be confirmed by the enzymatic activity of an enzyme (e.g., an enzymatic marker) that the heterologous sequence encodes. The enzyme can be assayed by a variety of methods known in the art. In general, the enzymatic activity can be ascertained by the formation of the product or conversion of a substrate of an enzymatic reaction that is under investigation. The reaction can take place in vitro or in vivo. 
     In one respect, the present disclosure provides an isolated host cell comprising the isolated nucleic acid or isolated nucleic acids or the vector or vectors according to the present disclosure. 
     The host cell may be a eukaryotic cell or a prokaryotic cell. An appropriate host cell may be transformed or transfected with the polynucleotide or vector of the present disclosure, and utilized for the expression and/or secretion of the heterodimer protein and/or protein mixtures. For example, the cell may be  E. coli  cells, other bacterial host cells, yeast cells, or various higher eukaryotic cells (e.g., immortal hybridoma cells, NSO myeloma cells, HEK293 cells, Chinese hamster ovary cells, HeLa cells, COS cells, etc.). In some embodiments, nucleic acids encoding the proteinaceous heterodimer (e.g., a heterodimer protein) are operably connected to an expression control sequence suitable for expression in specific host cells. 
     In one respect, the present disclosure provides a protein mixture. The protein mixture may comprise: 1) the proteinaceous heterodimer according to the present disclosure; 2) a first homodimer formed by two identical copies of the first monomeric member of the proteinaceous heterodimer according to the present disclosure; and 3) a second homodimer formed by two identical copies of the second monomeric member of the proteinaceous heterodimer according to the present disclosure. A percentage of the proteinaceous heterodimer in the protein mixture may be at least about 50%, at least about 55%, at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95% or at least about 99%. 
     In the protein mixture, the percentage of the second homodimer may be less than the percentage of the first homodimer. For example, the percentage of the second homodimer may be at most about 10%, at most about 9%, at most about 8%, at most about 7%, at most about 6%, at most about 5%, at most about 4%, at most about 3%, at most about 2%, at most about 1% or at most about 0.5%. For example, the protein mixture may substantially comprise none of the second homodimer. 
     The protein mixture may be produced directly by a host cell of the present disclosure, e.g., without enrichment/purification of the proteinaceous heterodimer and/or removing of the first or the second homodimer. 
     Pharmaceutical Compositions 
     In one respect, the present disclosure provides a pharmaceutical composition comprising the proteinaceous heterodimer according to the present disclosure; or the protein mixture according to the present disclosure, and optionally a pharmaceutically acceptable excipient. 
     Examples of pharmaceutically acceptable excipients include, but are not limited to inert solid diluents and fillers, diluents, sterile aqueous solution and various organic solvents, permeation enhancers, solubilizers and adjuvants. 
     In some embodiments, the proteinaceous heterodimer is formulated for oral administration, intravenous administration, intramuscular administration, in-situ administration at the site of a tumor, inhalation, rectal administration, vaginal administration, transdermal administration, or administration via subcutaneous repository. 
     The pharmaceutical composition may be used for inhibiting tumor growth. For example, the pharmaceutical compositions may inhibit or delay the development or progress of a disease, may reduce tumor size (and even substantially eliminate tumors), and may alleviate and/or stabilize a disease condition. 
     Described below are non-limiting exemplary pharmaceutical compositions and methods for preparing the same. 
     The subject pharmaceutical composition may, for example, be in a form suitable for oral administration as a tablet, capsule, pill, powder, sustained release formulations, solution, suspension, for parenteral injection as a sterile solution, suspension or emulsion, for topical administration as an ointment or cream or for rectal administration as a suppository. The pharmaceutical composition may be in unit dosage forms suitable for single administration of precise dosages. The pharmaceutical composition can further comprise a proteinaceous heterodimer (e.g., a heterodimer protein) or a protein mixture according to the present disclosure as an active ingredient and may include a conventional pharmaceutical carrier or excipient. Further, it may include other medicinal or pharmaceutical agents, carriers, adjuvants, etc. 
     Exemplary parenteral administration forms include, but not limited to, solutions or suspensions of an active proteinaceous heterodimer (e.g., a heterodimer protein) in sterile aqueous solutions, for example, aqueous propylene glycol or dextrose solutions. Such dosage forms can be suitably buffered with salts such as histidine and/or phosphate, if desired. 
     In some embodiments, the present disclosure provides a pharmaceutical composition for injection containing a proteinaceous heterodimer (e.g., a heterodimer protein) or a protein mixture of the present disclosure and a pharmaceutical excipient suitable for injection. 
     The forms in which the pharmaceutical compositions of the present disclosure may be incorporated for administration by injection include aqueous or oil suspensions, or emulsions, with sesame oil, corn oil, cottonseed oil, or peanut oil, as well as elixirs, mannitol, dextrose, or a sterile aqueous solution, and similar pharmaceutical vehicles. 
     In some embodiments, the present disclosure provides a pharmaceutical composition for oral administration containing a proteinaceous heterodimer (e.g., a heterodimer protein) or a protein mixture of the present disclosure, and a pharmaceutical excipient suitable for oral administration. 
     In some embodiments, the present disclosure provides a solid pharmaceutical composition for oral administration containing: (i) an amount of a proteinaceous heterodimer (e.g., a heterodimer protein) or a protein mixture of the disclosure; optionally (ii) an amount of a second agent; and (iii) a pharmaceutical excipient suitable for oral administration. In some embodiments, the composition further contains: (iv) an amount of a third agent. In some embodiments, amounts of the proteinaceous heterodimer or the protein mixture, second agent, and optional third agent are amounts that, alone or in combination, are effective in treating a condition of a subject. 
     In some embodiments, the pharmaceutical composition may be a liquid pharmaceutical composition suitable for oral consumption. Pharmaceutical compositions of the disclosure suitable for oral administration can be presented as discrete dosage forms, such as capsules, cachets, or tablets, or liquids or aerosol sprays each containing a predetermined amount of an active ingredient as a powder or in granules, a solution, or a suspension in an aqueous or non-aqueous liquid, an oil-in-water emulsion, or a water-in-oil liquid emulsion. Such dosage forms can be prepared by any of the methods of pharmacy, but all methods typically include the step of bringing the active ingredient into association with the carrier, which constitutes one or more other ingredients. In general, the compositions are prepared by uniformly and intimately admixing the active ingredient with liquid carriers or finely divided solid carriers or both, and then, if necessary, shaping the product into the desired presentation. 
     The present disclosure further encompasses anhydrous pharmaceutical compositions and dosage forms comprising an active ingredient (e.g., a proteinaceous heterodimer or a heterodimer protein of the present disclosure), since water can facilitate the degradation of some polypeptides. For example, water may be added (e.g., 5%) in the pharmaceutical arts as a means of simulating long-term storage in order to determine characteristics such as shelf-life or the stability of formulations over time. Anhydrous pharmaceutical compositions and dosage forms of the disclosure can be prepared using anhydrous or low moisture containing ingredients and low moisture or low humidity conditions. 
     A proteinaceous heterodimer (e.g., a heterodimer protein) or a protein mixture of the present disclosure can be combined in an intimate admixture with a pharmaceutical carrier according to conventional pharmaceutical compounding techniques. The carrier can take a wide variety of forms depending on the form of preparation desired for administration. In preparing the compositions for an oral dosage form, any of the usual pharmaceutical media can be employed as carriers, such as, for example, water, glycols, oils, alcohols, flavoring agents, preservatives, coloring agents, and the like in the case of oral liquid preparations (such as suspensions, solutions, and elixirs) or aerosols; or carriers such as starches, sugars, micro-crystalline cellulose, diluents, granulating agents, lubricants, binders, and disintegrating agents can be used in the case of oral solid preparations, in some embodiments without employing the use of lactose. If desired, tablets can be coated by standard aqueous or nonaqueous techniques. 
     When aqueous suspensions and/or elixirs are desired for oral administration, the active ingredient therein may be combined with various sweetening or flavoring agents, coloring matter or dyes and, if so desired, emulsifying and/or suspending agents, together with such diluents as water, ethanol, propylene glycol, glycerin and various combinations thereof. 
     The pharmaceutical compositions of the present disclosure may comprise a therapeutically effective amount of the active agent (e.g., the proteinaceous heterodimer or the protein mixture of the present disclosure). A therapeutically effective amount is an amount of the subject pharmaceutical composition capable of preventing and/or curing (at least partially) a condition or disorder (e.g., cancer) and/or any complications thereof in a subject suffering from or having a risk of developing said condition or disorder. The specific amount/concentration of the active agent comprised may vary according to the method of administration and the need of a patient, and can be determined based on e.g., volume, viscosity, and/or body weight of a patient etc. For example, an appropriate dosage may be about 0.1 mg or 1 mg/kg/day to about 50 mg/kg/day; sometimes, the dosage can be even higher. It shall be understood that these specific doses may be conveniently adjusted by a skilled person in the art (e.g., a doctor or a pharmacist) based on conditions of a specific patient, formulation, and/or disease. 
     Medical Use and Methods of Treatment 
     In one respect, the present disclosure provides a use of the proteinaceous heterodimer according to the present disclosure, or the protein mixture according to the present disclosure in the manufacture of a medicament and/or a kit for inhibiting growth of a tumor or a tumor cell. In some embodiments, the medicament and/or kit is used for specifically and/or preferentially inhibiting growth or differentiation of target cells (e.g., cancer cells) or killing target cells (e.g., cancer cells). 
     In one respect, the present disclosure provides a use of the proteinaceous heterodimer according to the present disclosure, or the protein mixture according to the present disclosure in the manufacture of a medicament for treating cancer in a subject in need thereof. 
     In one respect, the present disclosure provides a method for treating cancer in a subject in need thereof. The method may comprise administering to the subject an effective amount of the proteinaceous heterodimer according to the present disclosure, or the protein mixture according to the present disclosure. 
     In one respect, the present disclosure provides a method for inhibiting growth of a tumor or a tumor cell, comprising contacting the tumor or tumor cell with an effective amount of the proteinaceous heterodimer according to the present disclosure, or the protein mixture according to the present disclosure. The contacting may occur in vitro or in vivo. 
     In some embodiments, said contacting includes systemically or locally administering the proteinaceous heterodimer (e.g., a heterodimer protein), the protein mixture, the pharmaceutical composition or the medicament of the present disclosure to a subject (e.g., a mammal). In some embodiments, said contacting includes administering the proteinaceous heterodimer (e.g., a heterodimer protein), the protein mixture, the pharmaceutical composition, or the medicament of the present disclosure directly at the site of a tumor. In some embodiments, the administering is conducted by oral administration, intravenous administration, intramuscular administration, in-situ administration at the site of a tumor, inhalation, rectal administration, vaginal administration, transdermal administration or administration via subcutaneous repository. 
     In some embodiments, the tumor (e.g., cancer) or tumor cell (e.g., a cancer cell) is or is from a solid tumor. For example, the cancer may be selected from the group consisting of a B cell lymphoma, a lung cancer, a bronchus cancer, a colorectal cancer, a prostate cancer, a breast cancer, a pancreas cancer, a stomach cancer, an ovarian cancer, a urinary bladder cancer, a brain or central nervous system cancer, a peripheral nervous system cancer, an esophageal cancer, a cervical cancer, a melanoma, a uterine or endometrial cancer, a cancer of the oral cavity or pharynx, a liver cancer, a kidney cancer, a biliary tract cancer, a small bowel or appendix cancer, a salivary gland cancer, a thyroid gland cancer, a adrenal gland cancer, an osteosarcoma, a chondrosarcoma, a liposarcoma, a testes cancer, and a malignant fibrous histiocytoma. 
     In some embodiments, the cancer or cancer cell is within the body of a subject, e.g., a cancer or cancer cell within a human or in a non-human animal (e.g., a mammal). 
     In some embodiments, the mammal is a human. In some embodiments, the mammal is a mouse, a rat, a cat, a dog, a rabbit, a pig, a sheep, a horse, a bovine, a goat, a gerbil, a hamster, a guinea pig, a monkey or any other mammal. Many such mammals may be subjects that are known to the art as preclinical models for certain diseases or disorders, including solid tumors and/or other cancers (e.g., Talmadge et al., 2007 Am. J. Pathol. 170: 793; Kerbel, 2003 Canc. Biol. Therap. 2(4 Suppl 1): S134; Man et al., 2007 Canc. Met. Rev. 26: 737; Cespedes et al., 2006 Clin. TransL Oncol. 8: 318). 
     Method for Preparing Proteinaceous Heterodimers or Protein Mixtures 
     In one respect, the present disclosure provides a method for producing a proteinaceous heterodimer according to the present disclosure or a protein mixture according to the present disclosure. The method may comprise (i) culturing the host cell of the present disclosure under conditions to effect expression of the proteinaceous heterodimer, and (ii) harvesting the expressed proteinaceous heterodimer or a protein mixture comprising the proteinaceous heterodimer. 
     In some embodiments, the method does not comprise enriching the proteinaceous heterodimer in the products expressed by the host cells according to the present disclosure. 
     In some embodiments, the method does not comprise removing the first or the second homodimer from the protein mixture produced by the host cells according to the present disclosure. 
     In some embodiments, the method further comprises the steps of isolating and/or purifying the proteinaceous heterodimer or the protein mixture. 
     In some embodiments, the method further comprises transfecting/transforming host cells with polynucleotides/vectors encoding/expressing the heterodimer of the present disclosure, one or more members thereof, or fragments thereof. 
     In some embodiments, the proteinaceous heterodimer or the protein mixture of the present disclosure is produced by expressing a vector in a cell under conditions suitable for protein expression. In some embodiments, the proteinaceous heterodimer or the protein mixture of the present disclosure is produced by a single cell clone. 
     Factors that may vary among suitable conditions for protein expression include factors such as incubation time, temperature, and medium, and may depend on cell type and will be readily determined by one of ordinary skill in the art. 
     In some embodiments, during the process of producing the proteinaceous heterodimer or the protein mixture of the present disclosure, the host cells are grown in cultures, and in any apparatus that may be used to grow cultures, including fermenters. Cells may be grown as monolayers or attached to a surface. Alternatively, the host cells may be grown in suspension. The cells can be grown in a culture medium that is serum-free. The media can be a commercially available media, such as, but not limited to, Opti-CHO (Invitrogen, Catalogue #12681) supplemented with glutamine, such as 8 mM L-glutamine; RPMI 1640 medium, supplemented with 10% bovine calf serum, 10.5 ng/ml mIL-3 and L-glutamine; or 5% FCS medium. 
     The present disclosure also includes the following embodiments: 
     1. A proteinaceous heterodimer comprising a first monomeric member and a second monomeric member different from said first monomeric member, wherein: said first monomeric member comprises a first Fc subunit, said second monomeric member comprises a second Fc subunit, and said first monomeric member associates with said second monomeric member to form said heterodimer through complexation of said first Fc subunit with said second Fc subunit; wherein said proteinaceous heterodimer further comprises one or more interleukins fused to said first Fc subunit and/or said second Fc subunit; and wherein said proteinaceous heterodimer does not comprise any antibody heavy chain variable region or any antibody light chain variable region exhibiting binding specificity to a tumor antigen. 
     2. The proteinaceous heterodimer according to embodiment 1, wherein said one or more interleukins is fused to an amino-terminal amino acid and/or a carboxy-terminal amino acid of said first Fc subunit and/or said second Fc subunit. 
     3. The proteinaceous heterodimer according to any one of embodiments 1-2, which comprises two or more interleukins. 
     4. The proteinaceous heterodimer according to embodiment 3, wherein said two or more interleukins form one or more interleukin dimers, with each interleukin dimer comprising two interleukins fused to each other. 
     5. The proteinaceous heterodimer according to embodiment 4, wherein said two interleukins of each interleukin dimer are fused to each other through a peptide linker. 
     6. The proteinaceous heterodimer according to any one of embodiments 4-5, wherein said interleukin dimer is fused to an amino-terminal amino acid and/or a carboxy-terminal amino acid of said first Fc subunit and/or said second Fc subunit. 
     7. The proteinaceous heterodimer according to any one of embodiments 1-6, wherein one or more of said interleukins is fused to said first Fc subunit and/or said second Fc subunit through a peptide linker. 
     8. The proteinaceous heterodimer according to any one of embodiments 1-7, wherein at least one of said one or more interleukins is IL10. 
     9. The proteinaceous heterodimer according to any one of embodiments 4-8, wherein said one or more interleukin dimers comprises at least one IL10 dimer, and said IL10 dimer comprises two IL10. 
     10. The proteinaceous heterodimer according to any one of embodiments 1-9, wherein said first Fc subunit and/or said second Fc subunit is from an IgG molecule. 
     11. The proteinaceous heterodimer according to embodiment 10, wherein said IgG is selected from the group consisting of IgG1, IgG2, IgG3 and IgG4. 
     12. The proteinaceous heterodimer according to embodiment 11, wherein said IgG is a human IgG1. 
     13. The proteinaceous heterodimer according to any one of embodiments 1-12, wherein said proteinaceous heterodimer does not comprise any targeting moiety exhibiting binding specificity to any tumor antigen. 
     14. The proteinaceous heterodimer according to any one of embodiments 1-13, wherein said first Fc subunit is different from said second Fc subunit, and said first and/or second Fc subunit comprises a modification promoting heterodimerization between said first Fc subunit and said second Fc subunit. 
     15. The proteinaceous heterodimer according to embodiment 14, wherein said first Fc subunit comprises a first modification, and said second Fc subunit comprises a second modification. 
     16. The proteinaceous heterodimer according to embodiment 15, wherein said first modification comprises an amino acid substitution at position T366, and an amino acid substitution at one or more positions selected from the group consisting of: Y349, F405, K409, D399, K360, Q347, K392 and 5354, wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     17. The proteinaceous heterodimer according to embodiment 16, wherein the amino acid substitution comprised by the first modification is selected from the group consisting of: Y349C, Y349D, D399S, F405K, K360E, K409A, K409E, Q347E, Q347R, S354D, K392D and T366W. 
     18. The proteinaceous heterodimer according to any one of embodiments 15-17, wherein said first modification comprises 2-5 amino acid substitutions. 
     19. The proteinaceous heterodimer according to any one of embodiments 15-18, wherein said first modification comprises an amino acid substitution at a group of positions selected from any of the following groups: 1) Y349 and T366; 2) Y349, T366 and F405; 3) Y349, T366 and K409; 4) Y349, T366, F405, K360 and Q347; 5) Y349, T366, F405 and Q347; 6) Y349, T366, K409, K360 and Q347; 7) Y349, T366, K409 and Q347; 8) T366, K409 and K392; 9) T366 and K409; 10) T366, K409, Y349 and S354; 11) T366 and F405; 12) T366, F405 and D399; and 13) T366, F405, Y349 and S354; wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     20. The proteinaceous heterodimer according to any one of embodiments 15-19, wherein said first modification comprises a group of amino acid substitutions selected from any of the following groups: 1) Y349C and T366W; 2) Y349C, T366W and F405K; 3) Y349C, T366W and K409E; 4) Y349C, T366W and K409A; 5) Y349C, T366W, F405K, K360E and Q347E; 6) Y349C, T366W, F405K and Q347R; 7) Y349C, T366W, K409A, K360E and Q347E; 8) Y349C, T366W, K409A and Q347R; 9) T366W, K409A and K392D; 10) T366W and K409A; 11) T366W, K409A and Y349D; 12) T366W, K409A, Y349D and S354D; 13) T366W and F405K; 14) T366W, F405K and D399S; 15) T366W, F405K and Y349D; and 16) T366W, F405K, Y349D and S354D; wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     21. The proteinaceous heterodimer according to any one of embodiments 15-20, wherein said second modification comprises amino acid substitutions at positions T366, L368 and Y407, as well as an amino acid substitution at one or more positions selected from the group consisting of D356, D399, E357, F405, K360, K392, K409 and Q347, wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     22. The proteinaceous heterodimer according to embodiment 21, wherein the amino acid substitution comprised by the second modification is selected from the group consisting of D356C, D399S, E357A, F405K, K360E, K392D, K409A, L368A, L368G, Q347E, Q347R, T366S, Y407A and Y407V. 
     23. The proteinaceous heterodimer according to any one of embodiments 15-22, wherein the second modification comprises an amino acid substitution at 4-6 positions. 
     24. The proteinaceous heterodimer according to any one of embodiments 15-23, wherein the second modification comprises an amino acid substitution at a group of positions selected from any of the following groups: 1) D356, T366, L368, Y407 and F405; 2) D356, T366, L368 and Y407; 3) D356, T366, L368, Y407 and Q347; 4) D356, T366, L368, Y407, K360 and Q347; 5) D356, T366, L368, Y407, F405 and Q347; 6) D356, T366, L368, Y407, F405, K360 and Q347; 7) T366, L368, Y407, D399 and F405; 8) T366, L368, Y407 and F405; 9) T366, L368, Y407, F405 and E357; 10) T366, L368, Y407 and K409; 11) T366, L368, Y407, K409 and K392; and 12) T366, L368, Y407, K409 and E357; wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     25. The proteinaceous heterodimer according to any one of embodiments 15-24, wherein the second modification comprises a group of amino acid substitutions selected from any of the following groups: 1) D356C, T366S, L368A, Y407V and F405K; 2) D356C, T366S, L368A and Y407V; 3) D356C, T366S, L368A, Y407V and Q347R; 4) D356C, T366S, L368A, Y407V, K360E and Q347E; 5) D356C, T366S, L368A, Y407V, F405K and Q347R; 6) D356C, T366S, L368A, Y407V, F405K, K360E and Q347E; 7) T366S, L368A, Y407V, D399S and F405K; 8) T366S, L368G, Y407A and F405K; 9) T366S, L368A, Y407V, F405K and E357A; 10) T366S, L368A, Y407V and K409A; 11) T366S, L368A, Y407V, K409A and K392D; 12) T366S, L368G, Y407A and K409A; 13) T366S, L368A, Y407V, K409A and E357A; wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     26. The proteinaceous heterodimer according to any one of embodiments 15-25, wherein the first Fc subunit comprises the first modification, the second Fc subunit comprises the second modification, and the first modification and the second modification comprise an amino acid substitution at a group of positions selected from any of the following groups: 1) the first modification: Y349 and T366; and the second modification: D356, T366, L368, Y407 and F405; 2) the first modification: Y349, T366 and F405; and the second modification: D356, T366, L368 and Y407; 3) the first modification: Y349, T366 and K409; and the second modification: D356, T366, L368, Y407 and F405; 4) the first modification: Y349, T366, F405, K360 and Q347; and the second modification: D356, T366, L368, Y407 and Q347; 5) the first modification: Y349, T366, F405 and Q347; and the second modification: D356, T366, L368, Y407, K360 and Q347; 6) the first modification: Y349, T366, K409, K360 and Q347; and the second modification: D356, T366, L368, Y407, F405 and Q347; 7) the first modification: Y349, T366, K409 and Q347; and the second modification: D356, T366, L368, Y407, F405, K360 and Q347; 8) the first modification: T366, K409 and K392; and the second modification: T366, L368, Y407, D399 and F405; 9) the first modification: T366 and K409; and the second modification: T366, L368, Y407 and F405; 10) the first modification: T366, K409 and Y349; and the second modification: T366, L368, Y407, F405 and E357; 11) the first modification: T366, K409, Y349 and 5354; and the second modification: T366, L368, Y407, F405 and E357; 12) the first modification: T366 and F405; and the second modification: T366, L368, Y407 and K409; 13) the first modification: T366, F405 and D399; and the second modification: T366, L368, Y407, K409 and K392; 14) the first modification: T366, F405 and Y349; and the second modification: T366, L368, Y407, K409 and E357; 15) the first modification: T366, F405, Y349 and S354; and the second modification: T366, L368, Y407, K409 and E357; wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     27. The proteinaceous heterodimer according to any one of embodiments 15-26, wherein the first Fc subunit comprises the first modification, the second Fc subunit comprises the second modification, wherein the first modification and the second modification comprise a group of amino acid substitutions selected from any of the following groups: 1) the first modification: Y349C and T366W; and the second modification: D356C, T366S, L368A, Y407V and F405K; 2) the first modification: Y349C, T366W and F405K; and the second modification: D356C, T366S, L368A and Y407V; 3) the first modification: Y349C, T366W and K409E; and the second modification: D356C, T366S, L368A, Y407V and F405K; 4) the first modification: Y349C, T366W and K409A; and the second modification: D356C, T366S, L368A, Y407V and F405K; 5) the first modification: Y349C, T366W, F405K, K360E and Q347E; and the second modification: D356C, T366S, L368A, Y407V and Q347R; 6) the first modification: Y349C, T366W, F405K and Q347R; and the second modification: D356C, T366S, L368A, Y407V, K360E and Q347E; 7) the first modification: Y349C, T366W, K409A, K360E and Q347E; and the second modification: D356C, T366S, L368A, Y407V, F405K and Q347R; 8) the first modification: Y349C, T366W, K409A and Q347R; and the second modification: D356C, T366S, L368A, Y407V, F405K, K360E and Q347E; 9) the first modification: T366W, K409A and K392D; and the second modification: T366S, L368A, Y407V, D399S and F405K; 10) the first modification: T366W and K409A; and the second modification: T366S, L368G, Y407A and F405K; 11) the first modification: T366W, K409A and Y349D; and the second modification: T366S, L368A, Y407V, F405K and E357A; 12) the first modification: T366W, K409A, Y349D and S354D; and the second modification: T366S, L368A, Y407V, F405K and E357A; 13) the first modification: T366W and F405K; and the second modification: T366S, L368A, Y407V and K409A; 14) the first modification: T366W, F405K and D399S; and the second modification: T366S, L368A, Y407V, K409A and K392D; 15) the first modification: T366W and F405K; and the second modification: T366S, L368G, Y407A and K409A; 16) the first modification: T366W, F405K and Y349D; and the second modification: T366S, L368A, Y407V, K409A and E357A; 17) the first modification: T366W, F405K, Y349D and S354D; and the second modification: T366S, L368A, Y407V, K409A and E357A; wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     28. The proteinaceous heterodimer according to embodiment 27, wherein the first Fc subunit comprises the first modification, the second Fc subunit comprises the second modification, the first modification comprises the amino acid substitutions T366W and K409A, and the second modification comprises the amino acid substitutions T366S, L368G, Y407A and F405K, wherein the position of the amino acid is determined according to the EU index of the KABAT number. 
     29. The proteinaceous heterodimer according to any one of embodiments 1-28, wherein at least one of said one or more interleukins is fused to said second Fc subunit. 
     30. The proteinaceous heterodimer according to embodiment 29, wherein at least one of said one or more interleukins is fused to an amino-terminal amino acid of said second Fc subunit. 
     31. The proteinaceous heterodimer according to embodiment 30, wherein in said second monomeric member, at least two of said one or more interleukins are fused to each other to form an interleukin dimer, and said interleukin dimer is further fused to the amino-terminal amino acid of said second Fc subunit. 
     32. The proteinaceous heterodimer according to any one of embodiments 1-31, wherein said first monomeric member does not comprise any interleukin. 
     33. The proteinaceous heterodimer according to any one of embodiments 1-32, wherein said first monomeric member consists of said first Fc subunit. 
     34. The proteinaceous heterodimer according to any one of embodiments 1-31, wherein at least one of said one or more interleukins is fused to said first Fc subunit. 
     35. The proteinaceous heterodimer according to embodiment 34, wherein at least one of said one or more interleukins is fused to an amino-terminal amino acid of said first Fc subunit. 
     36. The proteinaceous heterodimer according to embodiment 35, wherein in said first monomeric member, at least two of said one or more interleukins are fused to each other to form an interleukin dimer, and said interleukin dimer is further fused to the amino-terminal amino acid of said first Fc subunit. 
     37. The proteinaceous heterodimer according to any one of embodiments 34-36, wherein said second monomeric member does not comprise any interleukin. 
     38. The proteinaceous heterodimer according to any one of embodiments 34-37, wherein said second monomeric member consists of said second Fc subunit. 
     39. An isolated nucleic acid or isolated nucleic acids encoding the proteinaceous heterodimer according to any one of embodiments 1-38. 
     40. A vector or vectors comprising the isolated nucleic acid or isolated nucleic acids according to embodiment 39. 
     41. An isolated host cell comprising the isolated nucleic acid or isolated nucleic acids according to embodiment 39 or the vector or vectors according to embodiment 40. 
     42. A protein mixture, comprising: 1) the proteinaceous heterodimer according to any one of embodiments 1-38; 2) a first homodimer formed by two identical copies of said first monomeric member according to any one of embodiments 1-38; and 3) a second homodimer formed by two identical copies of said second monomeric member according to any one of embodiments 1-38; wherein a percentage of said proteinaceous heterodimer in said protein mixture is at least 50%. 
     43. The protein mixture according to embodiment 42, wherein the percentage of the second homodimer is less than the percentage of the first homodimer. 
     44. The protein mixture according to any one of embodiments 42-43, wherein the percentage of the second homodimer is at most 10%. 
     45. The protein mixture according to any one of embodiments 42-44, wherein the protein mixture substantially comprises none of said second homodimer. 
     46. The protein mixture according to any one of embodiments 42-45, wherein the protein mixture is produced directly by a host cell, without enrichment of said proteinaceous heterodimer and/or removing of said first or said second homodimer. 
     47. A pharmaceutical composition comprising the proteinaceous heterodimer according to any one of embodiments 1-38; or the protein mixture according to any one of embodiments 42-46, and optionally a pharmaceutically acceptable excipient. 
     48. The pharmaceutical composition according to embodiment 47, wherein the proteinaceous heterodimer is formulated for oral administration, intravenous administration, intramuscular administration, in-situ administration at the site of a tumor, inhalation, rectal administration, vaginal administration, transdermal administration, or administration via subcutaneous repository. 
     49. Use of the proteinaceous heterodimer according to any one of embodiments 1-38, or the protein mixture according to any one of embodiments 42-46 in the manufacture of a medicament and/or a kit for inhibiting growth of a tumor or a tumor cell. 
     50. Use of the proteinaceous heterodimer according to any one of embodiments 1-38, or the protein mixture according to any one of embodiments 42-46 in the manufacture of a medicament for treating cancer in a subject in need thereof. 
     51. A method for inhibiting growth of a tumor or a tumor cell, comprising contacting said tumor or tumor cell with an effective amount of the proteinaceous heterodimer according to any one of embodiments 1-38, or the protein mixture according to any one of embodiments 42-46. 
     52. The method according to embodiment 51, wherein said contacting occurs in vitro or in vivo. 
     53. A method for treating cancer in a subject in need thereof, comprising administering to the subject an effective amount of the proteinaceous heterodimer according to any one of embodiments 1-38, or the protein mixture according to any one of embodiments 42-46. 
     54. A method for producing a proteinaceous heterodimer according to any one of embodiments 1-38 or a protein mixture according to any one of embodiments 42-46, comprising (i) culturing the host cell of embodiment 41 under conditions to effect expression of the proteinaceous heterodimer, and (ii) harvesting the expressed proteinaceous heterodimer or a protein mixture comprising said proteinaceous heterodimer. 
     While preferred embodiments of the present disclosure have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the disclosure. It should be understood that various alternatives to the embodiments of the disclosure described herein may be employed in practicing the disclosure. It is intended that the following claims define the scope of the disclosure and that methods and structures within the scope of these claims and their equivalents be covered thereby. 
     EXAMPLES 
     The examples and preparations provided below further illustrate and exemplify the proteinaceous heterodimer of the present disclosure and methods of using and preparing thereof. It is to be understood that the scope of the present disclosure is not limited in any way by the scope of the following examples and preparations. 
     Example 1 Modification and Preparation of Nucleic Acids 
     1.1 Fc Modifications 
     Amino acid modifications (e.g., amino acid substitutions) were made to the interface residues of human IgG1 Fc domain to obtain the following groups of modifications (as shown in table 1 below), chain A is also referred to as Fc9 or the first Fc subunit, and chain B is also referred to as Fc6 or the second Fc subunit in the present disclosure: 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Groups of amino acid modifications 
               
            
           
           
               
               
               
               
            
               
                 Group 
                 Fc Chain 
                 Modifications 
                 SEQ ID NO 
               
               
                   
               
            
           
           
               
               
               
               
            
               
                 1 
                 A 
                 Y349C + T366W 
                 1 
               
               
                   
                 B 
                 D356C + T366S + L368A + Y407V + F405K 
                 2 
               
               
                 2 
                 A 
                 Y349C + T366W + F405K 
                 3 
               
               
                   
                 B 
                 D356C + T366S + L368A + Y407V 
                 4 
               
               
                 3 
                 A 
                 Y349C + T366W + K409E 
                 5 
               
               
                   
                 B 
                 D356C + T366S + L368A + Y407V + F405K 
                 2 
               
               
                 4 
                 A 
                 Y349C + T366W + K409A 
                 6 
               
               
                   
                 B 
                 D356C + T366S + L368A + Y407V + F405K 
                 2 
               
               
                 5 
                 A 
                 Y349C + T366W + F405K + K360E + Q347E 
                 7 
               
               
                   
                 B 
                 D356C + T366S + L368A + Y407V + Q347R 
                 8 
               
               
                 6 
                 A 
                 Y349C + T366W + F405K + Q347R 
                 9 
               
               
                   
                 B 
                 D356C + T366S + L368A + Y407V + K360E + Q347E 
                 10 
               
               
                 7 
                 A 
                 Y349C + T366W + K409A + K360E + Q347E 
                 11 
               
               
                   
                 B 
                 D356C + T366S + L368A + Y407V + F405K + Q347R 
                 12 
               
               
                 8 
                 A 
                 Y349C + T366W + K409A + Q347R 
                 13 
               
               
                   
                 B 
                 D356C + T366S + L368A + Y407V + F405K + K360E + Q347E 
                 14 
               
               
                 9 
                 A 
                 T366W + K409A + K392D 
                 15 
               
               
                   
                 B 
                 T366S + L368A + Y407V + D399S + F405K 
                 16 
               
               
                 10 
                 A 
                 T366W + K409A 
                 17 
               
               
                   
                 B 
                 T366S + L368G + Y407A + F405K 
                 18 
               
               
                 11 
                 A 
                 T366W + K409A + Y349D 
                 19 
               
               
                   
                 B 
                 T366S + L368A + Y407V + F405K + E357A 
                 20 
               
               
                 12 
                 A 
                 T366W + K409A + Y349D + S354D 
                 21 
               
               
                   
                 B 
                 T366S + L368A + Y407V + F405K + E357A 
                 20 
               
               
                 13 
                 A 
                 T366W + F405K 
                 22 
               
               
                   
                 B 
                 T366S + L368A + Y407V + K409A 
                 23 
               
               
                 14 
                 A 
                 T366W + F405K + D399S 
                 24 
               
               
                   
                 B 
                 T366S + L368A + Y407V + K409A + K392D 
                 25 
               
               
                 15 
                 A 
                 T366W + F405K 
                 22 
               
               
                   
                 B 
                 T366S + L368G + Y407A + K409A 
                 26 
               
               
                 16 
                 A 
                 T366W + F405K + Y349D 
                 27 
               
               
                   
                 B 
                 T366S + L368A + Y407V + K409A + E357A 
                 28 
               
               
                 17 
                 A 
                 T366W + F405K + Y349D + S354D 
                 29 
               
               
                   
                 B 
                 T366S + L368A + Y407V + K409A + E357A 
                 28 
               
               
                   
               
            
           
         
       
     
     Subsequently, formation of heterodimer proteins comprising the groups of modifications listed in table 1 above were examined using a ScFv-Fc/Fc system, as explained in detail below. 
     First of all, human immunoglobulin gammal (IgG1) constant region amino acid sequence was obtained from the database Uniprot (P01857), to get wildtype human IgG1-Fc region amino acid sequence (SEQ ID NO:30). The polynucleotide fragment encoding wild type human IgG1-Fc was obtained by RT-PCR from human PBMC total RNA (SEQ ID NO: 31, named as the Fc gene fragment). A polynucleotide fragment encoding a mouse kappaIII signal peptide (SEQ ID NO:32) was added to the 5′ end of the Fc gene by overlapping PCR, and then subcloned into the vector pcDNA4 (Invitrogen, Cat V86220), to obtain a recombinant expression vector for expressing human IgG1-Fc in mammalian cells. 
     A nucleic acid molecule encoding a ScFv-Fc fusion protein (SEQ ID NO:33) was synthesized, wherein the ScFv refers to an anti-HER2 single chain antibody, the amino acid sequence of the ScFv-Fc fusion protein is as set forth in SEQ ID NO: 34. The ScFv-Fc gene fragment was then subcloned into the vector pcDNA4 (Invitrogen, Cat V86220), to obtain a recombinant expression vector for expressing the ScFv-Fc fusion protein in mammalian cells. 
     In some cases, a polypeptide encoding a variable region of a camel single domain antibody (VhH) was fused to the N terminal of the Fc gene fragment to obtain a fusion gene fragment (as set forth in SEQ ID NO: 35) encoding the fusion protein VhH-Fc (as set forth in SEQ ID NO: 36). It was then subcloned into the vector pcDNA4 (Invitrogen, Cat V86220), to obtain a recombinant expression vector for expressing the fusion protein VhH-Fc in mammalian cells. 
     Then, the amino acid modifications as listed in table 1 above were respectively introduced into the ScFv-Fc (groups 1-17), the VhH-Fc (groups 9-12, 14, 15 and 17), and the Fc gene fragment (groups 1-8) by overlapping PCR, wherein chain A refers to the Fc subunit in ScFv-Fc and chain B refers to the independent Fc subunit or the Fc subunit in VhH-Fc. The gene fragments with amino acid modifications were respectively subcloned into the vector pcDNA4 (Invitrogen, Cat V86220), to obtain recombinant expression vectors for expressing the modified ScFv-Fc fusion proteins, the modified Fc proteins, and the modified VhH-Fc fusion proteins in mammalian cells. Then, suspend-cultured HEK293 cells (ATCC CRL-1573™) were transfected with the constructed expression vectors with PEI. For each group, the expression vector expressing the A chain (ScFv-Fc fusion protein) and that expressing the B chain (Fc protein or VhH-Fc fusion protein) were co-transfected at a ratio of 1:1. After culturing for 5-6 days, supernatant of the transient expression products was collected, and the expression products comprising corresponding protein heterodimers were preliminarily purified using ProteinA affinity chromatography. Each of the preliminarily purified expression products comprises the homodimer protein ScFv-Fc/ScFv-Fc, the homodimer protein Fc/Fc (or the homodimer protein VhH-Fc/VhH-Fc) and the heterodimer protein ScFv-Fc/Fc (or the heterodimer protein ScFv-Fc/VhH-Fc), present in various percentages, respectively. Since the molecular weight of these proteins (i.e., the homodimers and the heterodimers) are different, their corresponding percentage could be determined according to corresponding band intensities reflected on non-reduced SDS-PAGE gels. The intensities were quantified and the results are summarized in tables 2-5 below. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Percentage of homodimer proteins and heterodimer 
               
               
                 proteins in expression products 
               
            
           
           
               
               
               
               
            
               
                   
                 ScFv-Fc 
                 ScFv-Fc/Fc 
                 Fc 
               
               
                 Group 
                 homodimer (%) 
                 heterodimer (%) 
                 homodimer (%) 
               
               
                   
               
               
                 1 
                 24 
                 58 
                 18 
               
               
                 2 
                 10 
                 70 
                 20 
               
               
                 3 
                 25 
                 57 
                 18 
               
               
                 4 
                 10 
                 77 
                 13 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Percentage of homodimer proteins and heterodimer 
               
               
                 proteins in expression products 
               
            
           
           
               
               
               
               
            
               
                   
                 ScFv-Fc 
                 ScFv-Fc/Fc 
                 Fc 
               
               
                 Group 
                 homodimer (%) 
                 heterodimer (%) 
                 homodimer (%) 
               
               
                   
               
            
           
           
               
               
               
               
            
               
                 2 
                 17 
                 60 
                 23 
               
               
                 5 
                 14 
                 72 
                 14 
               
               
                 6 
                 14 
                 62 
                 24 
               
               
                 4 
                 21 
                 69 
                 10 
               
               
                 7 
                 24 
                 64 
                 12 
               
               
                 8 
                 21 
                 71 
                 8 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Percentage of homodimer proteins and heterodimer 
               
               
                 proteins in expression products 
               
            
           
           
               
               
               
               
            
               
                   
                 ScFv-Fc 
                 ScFv-Fc/VhH-Fc 
                 VhH-Fc 
               
               
                 Group 
                 homodimer (%) 
                 heterodimer (%) 
                 homodimer (%) 
               
               
                   
               
            
           
           
               
               
               
               
            
               
                 4 
                 13 
                 68 
                 19 
               
               
                 9 
                 7 
                 80 
                 13 
               
               
                 10 
                 15 
                 85 
                 0 
               
               
                 11 
                 14 
                 83 
                 3 
               
               
                 12 
                 10 
                 84 
                 6 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                 Percentage of homodimer proteins and heterodimer 
               
               
                 proteins in expression products 
               
            
           
           
               
               
               
               
            
               
                   
                 ScFv-Fc 
                 ScFv-Fc/VhH-Fc 
                 VhH-Fc 
               
               
                 Group 
                 homodimer (%) 
                 heterodimer (%) 
                 homodimer (%) 
               
               
                   
               
            
           
           
               
               
               
               
            
               
                 2 
                 9 
                 64 
                 27 
               
               
                 14 
                 6 
                 81 
                 13 
               
               
                 15 
                 5 
                 88 
                 7 
               
               
                 17 
                 9 
                 84 
                 7 
               
               
                   
               
            
           
         
       
     
     As can be seen from tables 2-5 above, all groups of modifications promoted heterodimer formation very effectively. For illustrative purposes, the modifications in group 10 (modifications in chain A: T366W+K409A; modifications in chain B: T366S+L368G+Y407A+F405K) were used in the following examples to generate the immunoconjugate or the protein mixtures of the present disclosure. 
     1.2 Preparation of (IL10) 2 -Fc6 
     First of all, sequence information of human interleukin 10 (IL10) (P22301) was obtained from the National Center for Biotechnology Information (NCBI), and the full length polynucleotide sequences encoding it were obtained. Then, amino acid sequences of human IgG1-Fc (i.e., residue 104 to residue 330 of P01857) were obtained according to the amino acid sequences of human immunoglobulin γ1 (IgG1) constant region (P01857) from the protein database Uniprot. Afterwards, point mutations (T366S, L368G, Y407A and F405K) were introduced into the IgG1-Fc fragment, and the polypeptide obtained thereby is referred to as Fc6. Then, a linker sequence “(GGGGS) 3 ” (SEQ ID NO: 37) was added to the N-terminus of the Fc6, to obtain linker-Fc6. The corresponding DNA sequence encoding it was then designed using online tool DNAworks (helixweb.nih.gov/dnaworks/). Then, a linker sequence “(GGGGS) 3 ” (SEQ ID NO: 37) was added between two copies of IL10, to obtain (IL10) 2 . Polynucleotide sequences encoding (IL10) 2  were then added to the 5′ end of the polynucleotide sequences encoding the linker-Fc6, thereby obtaining and synthesizing a polynucleotide sequence encoding the fusion protein (IL10) 2 -Fc6. The amino acid sequence of (IL10) 2 -Fc6 is as set forth in SEQ ID NO: 38, and the polynucleotide sequence encoding it is as set forth in SEQ ID NO: 39. 
     1.3 Preparation of IL10-Fc 
     First of all, sequence information of human interleukin 10 (IL10) (P22301) was obtained from the National Center for Biotechnology Information (NCBI), and the full length polynucleotide sequences encoding it were obtained. Then, amino acid sequences of human IgG1-Fc (i.e., residue 104 to residue 330 of P01857) were obtained according to the amino acid sequences of human immunoglobulin γ1 (IgG1) constant region (P01857) from the protein database Uniprot. Then, a linker sequence “(GGGGS) 3 ” (SEQ ID NO: 37) was added to the N-terminus of IgG1-Fc, to obtain linker-Fc. The corresponding DNA sequence encoding it was then designed using online tool DNAworks (helixweb.nih.gov/dnaworks/). Polynucleotide sequences encoding IL10 were added to the 5′ end of the polynucleotide sequences encoding the linker-Fc, thereby obtaining and synthesizing a polynucleotide sequence encoding the fusion protein IL10-Fc. The amino acid sequence of IL10-Fc is as set forth in SEQ ID NO: 40, and the polynucleotide sequence encoding it is as set forth in SEQ ID NO: 41. 
     1.4 Preparation of Fc9 
     Amino acid sequences of human IgG1-Fc (i.e., residue 104 to residue 330 of P01857) were obtained according to the amino acid sequences of human immunoglobulin γ1 (IgG1) constant region (P01857) from the protein database Uniprot. Afterwards, point mutations (T366W and K409A) were introduced into the IgG1Fc fragment, and the polypeptide obtained thereby is referred to as Fc9. The amino acid sequence of Fc9 is as set forth in SEQ ID NO: 17, and the polynucleotide sequence encoding it is as set forth in SEQ ID NO: 42. 
     1.5 Preparation of Anti-EGFR (Cetuximab) 
     Full length amino acid sequences of the heavy chain and light chain of Cetuximab (also known as Erbitux or Erb, which is an antibody against epidermal growth factor receptor EGFR) were obtained, and corresponding DNA sequences encoding these amino acid sequences were obtained using online tool DNAworks (helixweb.nih.gov/dnaworks/). Then, nucleic acid molecules encoding the light chain of Cetuximab (Erb-LC) were synthesized. The amino acid sequence of Erb-LC is as set forth in SEQ ID NO: 43, and the corresponding polynucleotide sequence encoding it is as set forth in SEQ ID NO:44. Then, point mutations (T366W and K409A) were introduced into the polynucleotide sequences encoding the Fc region of Cetuximab heavy chain gene, and nucleic acid molecules encoding the modified Cetuximab heavy chain were synthesized (referred to herein as Erb-Fc9), the corresponding polypeptide encoding it was named as Erb-Fc9. The amino acid sequences of Erb-Fc9 is as set forth in SEQ ID NO: NO: 45, and the polynucleotide sequence encoding it is as set forth in SEQ ID NO: NO: 46. 
     1.6 Preparation of (IL10) 2 -Fc 
     First of all, sequence information of human interleukin 10 (IL10) (P22301) was obtained from the National Center for Biotechnology Information (NCBI), Then, a linker sequence “(GGGGS) 3 ” was added between two IL10, to get (IL10) 2 , and the full length polynucleotide sequences encoding it were obtained. Then, amino acid sequences of human IgG1-Fc (i.e., residue 104 to residue 330 of P01857) were obtained according to the amino acid sequences of human immunoglobulin γ1 (IgG1) constant region (P01857) from the protein database Uniprot. Then, a linker sequence “(GGGGS) 3 ” (SEQ ID NO: 37) was added to the N-terminus of IgG1-Fc, to obtain linker-Fc. The corresponding DNA sequence encoding it was then designed using online tool DNAworks (helixweb.nih.gov/dnaworks/). Polynucleotide sequences encoding (IL10) 2  were added to the 5′ end of the polynucleotide sequences encoding the linker-Fc, thereby obtaining and synthesizing a polynucleotide sequence encoding the fusion protein (IL10) 2 -Fc. The amino acid sequence of (IL10) 2 -Fc is as set forth in SEQ ID NO: 47 and the polynucleotide sequence encoding it is as set forth in SEQ ID NO: 48. 
     1.7 Preparation of Fc6-(IL10) 2    
     First of all, sequence information of human interleukin 10 (IL10) (P22301) was obtained from the National Center for Biotechnology Information (NCBI), and the full length polynucleotide sequences encoding it were obtained. Then, amino acid sequences of human IgG1-Fc (i.e., residue 104 to residue 330 of P01857) were obtained according to the amino acid sequences of human immunoglobulin γ1 (IgG1) constant region (P01857) from the protein database Uniprot. Afterwards, point mutations (T366S, L368G, Y407A and F405K) were introduced into the IgG1-Fc fragment, and the polypeptide obtained thereby is referred to as Fc6. 
     Then, a linker sequence “(GGGGS) 3 ” (SEQ ID NO: 37) was added to the C-terminus of the Fc6, to obtain Fc6-linker. The corresponding DNA sequence encoding it was then designed using online tool DNAworks (helixweb.nih.gov/dnaworks/). Then, a linker sequence “(GGGGS) 3 ” (SEQ ID NO: 37) was added between two copies of IL10, to obtain (IL10) 2 . Polynucleotide sequences encoding (IL10) 2  were then added to the 3′ end of the polynucleotide sequences encoding the Fc6-linker, thereby obtaining and synthesizing a polynucleotide sequence encoding the fusion protein Fc6-(IL10) 2 . The amino acid sequence of Fc6-(IL10) 2  is as set forth in SEQ ID NO: 55, and the polynucleotide sequence encoding it is as set forth in SEQ ID NO: 56. 
     1.8 Preparation of IL10-Fc6 
     First of all, sequence information of human interleukin 10 (IL10) (P22301) was obtained from the National Center for Biotechnology Information (NCBI), and the full length polynucleotide sequences encoding it were obtained. Then, amino acid sequences of human IgG1-Fc (i.e., residue 104 to residue 330 of P01857) were obtained according to the amino acid sequences of human immunoglobulin γ1 (IgG1) constant region (P01857) from the protein database Uniprot. Afterwards, point mutations (T366S, L368G, Y407A and F405K) were introduced into the IgG1-Fc fragment, and the polypeptide obtained thereby is referred to as Fc6. Then, a linker sequence “(GGGGS) 3 ” (SEQ ID NO: 37) was added to the N-terminus of the Fc6, to obtain linker-Fc6. The corresponding DNA sequence encoding it was then designed using online tool DNAworks (helixweb.nih.gov/dnaworks/). Polynucleotide sequences encoding IL10 were added to the 5′ end of the polynucleotide sequences encoding the linker-Fc6, thereby obtaining and synthesizing a polynucleotide sequence encoding the fusion protein IL10-Fc6. The amino acid sequence of IL10-Fc6 is as set forth in SEQ ID NO: 53, and the polynucleotide sequence encoding it is as set forth in SEQ ID NO: 54. 
     1.9 Preparation of (IL10) 2 -Fc9 
     First of all, sequence information of human interleukin 10 (IL10) (P22301) was obtained from the National Center for Biotechnology Information (NCBI), and the full length polynucleotide sequences encoding it were obtained. Then, (i.e., residue 104 to residue 330 of P01857) were obtained according to the amino acid sequences of human immunoglobulin γ1 (IgG1) constant region (P01857) from the protein database Uniprot. Afterwards, point mutations (T366W and K409A) were introduced into the IgG1Fc fragment, and the polypeptide obtained thereby is referred to as Fc9. Then, a linker sequence “(GGGGS) 3 ” (SEQ ID NO: 37) was added to the N-terminus of the Fc9, to obtain linker-Fc9. The corresponding DNA sequence encoding it was then designed using online tool DNAworks (helixweb.nih.gov/dnaworks/). Then, a linker sequence “(GGGGS) 3 ” (SEQ ID NO: 37) was added between two copies of IL10, to obtain (IL10) 2 . Polynucleotide sequences encoding (IL10) 2  were then added to the 5′ end of the polynucleotide sequences encoding the linker-Fc9, thereby obtaining and synthesizing a polynucleotide sequence encoding the fusion protein (IL10) 2 -Fc9. The amino acid sequence of (IL10) 2 -Fc9 is as set forth in SEQ ID NO: 57, and the polynucleotide sequence encoding it is as set forth in SEQ ID NO: 58. 
     1.10 Preparation of Fc6 
     Amino acid sequences of human IgG1-Fc (i.e., residue 104 to residue 330 of P01857) were obtained according to the amino acid sequences of human immunoglobulin γ1 (IgG1) constant region (P01857) from the protein database Uniprot. Afterwards, point mutations (T366S, L368G, Y407A and F405K) were introduced into the IgG1Fc fragment, and the polypeptide obtained thereby is referred to as Fc6. The amino acid sequence of Fc6 is as set forth in SEQ ID NO: 18, and the polynucleotide sequence encoding it is as set forth in SEQ ID NO: 59. 
     Example 2 Construction of Recombinant Plasmids 
     The nucleic acid molecules (encoding (IL10) 2 -Fc6, IL10-Fc, Fc9, Erb-Fc9, Erb-LC, (IL10) 2 -Fc, Fc6-(IL10) 2 , IL10-Fc6, (IL10) 2 -Fc9 and Fc6) obtained according to Example 1 were digested with HindIII and EcoRI (Takara), and then sub-cloned into the vector pcDNA4/myc-HisA (Invitrogen, V863-20), respectively. The plasmids obtained were verified by sequencing, and the correct recombinant plasmids were named as: pcDNA4-(IL10) 2 -Fc6, pcDNA4-IL10-Fc, pcDNA4-Fc9, pcDNA4-Erb-Fc9, pcDNA4-Erb-LC, pcDNA4-(IL10) 2 -Fc, pcDNA4-Fc6-(IL10) 2 , pcDNA4-IL10-Fc6, pcDNA4-(IL10) 2 -Fc9 and pcDNA4-Fc6 respectively. 
     Example 3 Expression and Purification of the Proteinaceous Heterodimers 
     Two days before transfection, 12× 600 mL suspension domesticated HEK293 (ATCC, CRL-1573™) cells were prepared for transient transfection, the cells were seeded at a density of 0.8×10 6  cells/ml. Two days later, three aliquots of cell suspension were centrifuged, and then resuspended in 600 mL Freestyle293 culture medium. 
     The recombinant expression vectors obtained from Example 2 were divided into the following groups: 
     Group A: pcDNA4-IL10-Fc6 (200 μg)+pcDNA4-Fc9(200 μg) 
     Group B: pcDNA4-(IL10) 2 -Fc6 (200 μg)+pcDNA4-Fc9(200 μg) 
     Group C: pcDNA4-Fc6-(IL10) 2  (200 μg)+pcDNA4-Fc9(200 μg) 
     Group D: pcDNA4-(IL10) 2 -Fc9 (200 μg)+pcDNA4-Fc6 (200 μg) 
     Group E: pcDNA4-Erb-Fc9 (200 μg)+pcDNA4-Erb-LC (200 μg)+pcDNA4-(IL10) 2 -Fc6 (200 μg) 
     Group F: pcDNA4-IL10-Fc (200 μg) 
     Group G: pcDNA4-(IL10) 2 -Fc (200 μg) 
     All proteins were made in transiently transfected 293F cells. Briefly, FreeStyle 293F cells (Invitrogen) were grown in 293F medium (Invitrogen), transfected with non-linearized plasmid DNA and 293Fectin reagent (Invitrogen) and grown in shaker flask batches in volumes 80-100 mL/flask at 37° C., 5% CO 2  for 6 days. All proteins were purified by one-step protein A chromatography. The quality of each protein was determined by SDS-PAGE and SEC-HPLC. Similarly, the expression and purification results of the other proteinaceous heterodimers of the present application were verified and confirmed with SDS-PAGE. 
     The proteinaceous heterodimers thus obtained are named as (from Group A-E, respectively): IL10-Fc9, (IL10) 2 -Fc9, reverse-(IL10) 2 -Fc9, (IL10) 2 -Fc6 (shown in  FIGS. 1A-1D , respectively) and Erb-(IL10) 2 , and the proteinaceous homodimers obtained from Group F-G is named as (IL10-Fc) 2  and (IL10) 2 -Fc. 
       FIGS. 2A-2F  show, as examples, that the proteinaceous heterodimers of (IL10) 2 -Fc9 and Erb-(IL10) 2  were successfully expressed and purified. All the other proteins were also obtained similarly. 
     In  FIG. 2A , lane 1 was loaded with Erb-(IL10) 2  (reducing); lane 2 was loaded with marker; lane 3 was loaded with Erb-(IL10) 2  (non-reducing). 
     In  FIG. 2B , lane 1 was loaded with (IL10-Fc) 2  (original sample); lane 2 was loaded with (IL10-Fc) 2  (flow-through); lane 3 was loaded with (IL10-Fc) 2  (eluted); lane 4 was loaded with marker; lane 5 was loaded with (IL10)2-Fc (eluted); lane 6 was loaded with (IL10) 2 -Fc (original sample); lane 7 was loaded with (IL10) 2 -Fc (flow through); lane 8 was loaded with BSA; lane 9 was loaded with blank buffer; lane10 was blank; lane 11 was loaded with (IL10) 2 -Fc (eluted; non-reducing); and lane 12 was loaded with (IL10) 2 -Fc (eluted; non-reducing). 
     In  FIG. 2C , lane 1 was loaded with (IL10) 2 -Fc9 (original sample); lane 2 was loaded with (IL10) 2 -Fc9 (flow-through); lane 3 was loaded with (IL10) 2 -Fc9 (eluted); lane 4 was loaded with marker; lane 5 was loaded with BSA; lane 6 was loaded with blank buffer; lane 7 was blank; lane 8 was loaded with (IL10) 2 -Fc9 (eluted; non-reducing). 
       FIG. 2D  shows the SEC-HPLC result, it can be seen that the percentage of undesired oligomers in the expression products of (IL10-Fc) 2  was about 27%. 
       FIG. 2E  shows the SEC-HPLC result, it can be seen that the percentage of undesired oligomers in the expression products of (IL10) 2 -Fc9 was about 3.3%. 
       FIG. 2F  shows the SEC-HPLC result, it can be seen that the percentage of undesired oligomers in the expression products of (IL10) 2 -Fc was about 26%. 
     From these results, it can be seen that the proteinaceous heterodimers of the present disclosure have been successfully produced. Interestingly, the expression products of (IL10) 2 -Fc9 contain much less undesired oligomers than the homodimer controls (IL10-Fc) 2  and (IL10) 2 -Fc. 
     Example 4 Identification of Characteristics of Heterodimer Proteins 
     4.1 Detection on the Capacity of Binding to Human IL10R1 Proteins (ELISA) 
     Human IL10R1 (R&amp;D, 9100-R1-050) was diluted to 5 μg/mL with coating buffer (50 mM Na 2 CO 3 , NaHCO 3  pH 9.6), 100 μL/well, overnight at 4° C. After washing, the plates were sealed with 3% BSA-PBS for 1 h at 37° C. Then, all samples were respectively diluted from 10000 ng/mL and were diluted 3-fold to a total of 11 concentrations, with the diluent (1% BSA-PBS) as a control, incubated at 37° C. for 2 h. After washing, Goat anti-hIgG-HRP (Sigma, A0170) was added and incubated at 37° C. for 1 h. The soluble one-component TMB substrate developing solution was added, and the developing was performed in dark at room temperature for 5-10 min. 2 N H 2 SO 4  50 μL/well was added to terminate the color development reaction. The PD 450 nm  values were read on MD SpectraMax Plus 384 microplate Reader, and SoftMax Pro v5.4 was used for data processing and diagraph analysis, with the results shown in  FIG. 3  and Table 6. 
     
       
         
           
               
             
               
                 TABLE 6 
               
             
            
               
                   
               
               
                 EC 50  of hetero dimer proteins in binding to human IL10R1 proteins 
               
            
           
           
               
               
               
            
               
                   
                 Name of heterodimer proteins 
                 EC 50  (ng/ml) 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                   
                 Erb-(IL10) 2   
                 2.940 
               
               
                   
                 Reverse-(IL10) 2 -Fc9 
                 12.31 
               
               
                   
                 (IL10) 2 -Fc6 
                 7.166 
               
               
                   
                 (IL10) 2 -Fc9 
                 9.683 
               
               
                   
                   
               
            
           
         
       
     
     As shown in  FIG. 3 , the affinity between Erb-(IL10) 2  and hIL10R1 was the highest. The binding affinities of Reverse-(IL10) 2 -Fc9, (IL10) 2 -Fc6 and (IL10) 2 -Fc9 with hIL10R1 were similar to each other. 
     4.2 Enhancement of Proliferation of MC/9 Cells 
     MC/9 (ATCC CRL-8306) cells were seeded into 96-well plates at 100 μL/well. The amount of MC/9 was 5×10 4 /well. All samples were diluted to a maximum concentration of 2×10 4  pM. Then the samples were diluted 4 times to a total of 9 concentrations, 100 μL/well. For the control group, 100 μL of DMEM medium was added. Each sample was done in duplicate. Then incubate for 2 days at 37° C. with 5% CO 2 . Then discard 140 μL/well of the supernatant, and add 60 μL/well CellTiter-Glo Cell Activity Assay Agent(Promega G7571). Incubate for 15 min (100 rpm) with an orbital shaker in dark. Then transfer 100 μL/well of the supernatant to a new 96-well white plate, and measure the luminescence at the full wavelength with MD Spectra Max Plus 384 microplate reader, with the results shown in  FIG. 4 . 
     As shown in  FIG. 4 , (IL10)2-Fc9 and (IL10)2-Fc6 proliferated nearly at the same level in vitro in MC/9 cell line. Reverse-(IL10)2-Fc9 has better proliferative effects than (IL10)2-Fc9. The in vitro function studies using MC/9 cells showed similar biological activity between (IL10)2-Fc9 and (IL10)2-Fc6 while reverse-(IL10)2-Fc9 showed higher biological activity. 
     Example 5 Tumor Control 
     5.1 Animals and Cell Culture 
     Female C57BL/6 mice were obtained from the Experimental Animal Centre of Chinese Academy of Science (Shanghai, China) at 8-week-old and maintained under specific pathogen-free conditions. All animals were used in accordance with the local ethics committee. This study was approved by the recommendations in the Guide for the Care and Use of Medical Laboratory Animals (Ministry of Health, People&#39;s Republic of China, 1998). The B16F10 melanoma cell line was generated in house and grown in DMEM medium supplemented with 10% (v/v) fetal bovine serum (FBS), 100 units/ml penicillin, and 100 μg/ml streptomycin (Gibco Invitrogen). 
     5.2 Tumor Growth 
     B16F10 cells (5×10 6 ) were inoculated subcutaneously (s.c.) into the flanks of mice and allowed to grow for about 7 days. Tumor volumes were recorded to be two perpendicular diameters (length and width) and calculated as V=ab 2 /2, where a and b are the longest and the shortest diameter, respectively. After 7 days, the tumor volume was measured to be around 70 mm 3 . 
     5.3 Treatment 
     After 7 days of the implantation of B16F10 cells, (IL10) 2 -Fc9 or isotype (hIgG) was injected intraperitoneally (i.p.) or intratumorally (i.t.) with the dosage of 0.5 mg/kg and 2.5 mg/kg, respectively. Dosing was administered twice per week, 3 times in total. Tumor size was measured twice per week, and the volume of the tumors was calculated to obtain a curve of tumor growth. The results are demonstrated in  FIGS. 5A-5B . In  FIG. 5A , the horizontal ordinate is the days after the implantation of B16F10 cells, and the vertical ordinate is the average volume of tumor, and it can be seen that (IL10) 2 -Fc9 effectively reduced tumor volume in vivo when administered i.p. or i.t., while the control isotype couldn&#39;t.  FIG. 5B  shows the tumor volume on day 22 with the treatment of (IL10) 2 -Fc9 (i.p. and i.t.) with different dosage. The measurement of tumor size was repeated by 5 times. It can be seen that (IL10) 2 -Fc9, when administered i.p. and i.t. in different doses, reduced tumor volume in vivo. 
     Example 6 Effects of Proteinaceous Heterodimers in Tumor Control 
     6.1 Effects of (IL10) 2 -Fc9 According to the Present Disclosure (High Concentration) 
     The C57BL/6 tumor control model was obtained as described above in Example 5. The mice were divided into two groups with 5 mice per group: Group isotype control, treated with 0.65 mg/kg human IgG1; Group (IL10) 2 -Fc9, treated with 0.65 mg/kg (IL10) 2 -Fc9. C57BL/6 mice were inoculated s.c. with B16F10-EGFR5 cells on day 0; (IL10) 2 -Fc9 or human IgG1 was injected i.p. on day 7, 10, 14 respectively. 
       FIG. 6A  shows the effects on tumor grow for isotype control and (IL10) 2 -Fc9 of the present disclosure. It can be seen that (IL10) 2 -Fc9 effectively reduced tumor volume in vivo, while the isotype control couldn&#39;t. 
     6.2 Effects of (IL10) 2 -Fc9 According to the Present Disclosure (Low Concentration) 
     The C57BL/6 tumor control model was obtained as described above in Example 5. The mice were divided into two groups with 5 mice per group: Group isotype control, treated with 0.5 mg/kg human IgG1; Group (IL10) 2 -Fc9, treated with 0.13 mg/kg (IL10) 2 -Fc9 C57BL/6 mice were inoculated s.c. with B16F10-EGFR5 cells on day 0; (IL10) 2 -Fc9 or human IgG1 was injected i.p. on day 7, 10, 14 respectively. 
       FIG. 6B  shows the effects on tumor grow for isotype control and (IL10) 2 -Fc9 of the present disclosure. It can be seen that (IL10) 2 -Fc9 effectively reduced tumor volume in vivo, while the isotype control could not. Compared with the result in Example 6.1, the low concentration of (IL10) 2 -Fc9 did not influence the result of tumor control effects. 
     While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. It is not intended that the invention be limited by the specific examples provided within the specification. While the invention has been described with reference to the aforementioned specification, the descriptions and illustrations of the embodiments herein are not meant to be construed in a limiting sense. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. Furthermore, it shall be understood that all aspects of the invention are not limited to the specific depictions, configurations or relative proportions set forth herein which depend upon a variety of conditions and variables. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is therefore contemplated that the invention shall also cover any such alternatives, modifications, variations or equivalents. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.