Patent Publication Number: US-2022213160-A1

Title: Protein heterodimer and use thereof

Description:
TECHNICAL FIELD 
     The present application relates to the field of tumor treatment, and in particular, relates to a protein heterodimer and uses thereof. 
     BACKGROUND ART 
     Tumor is a disease that seriously threatens the health of human beings. In recent years, immunotherapy, as a new therapy, has shown great potential in tumor treatment. Cytokine is a very important immune signal in the body, and cytokine fusion protein technology is another popular field for tumor immunotherapy today. This technology is to fuse two or more types of cytokines together by using the genetic engineering technology based on the fact that these cytokines have the same or related functional activities but with different targets respectively. However, the current tumor treatment using the cytokine fusion protein technology is still unsatisfactory, and there is much room for improvement. 
     SUMMARY OF THE INVENTION 
     The present application provides a protein heterodimer, comprising a first polypeptide chain and a second polypeptide chain different from the first polypeptide chain, wherein the first polypeptide chain comprises IL12a, and the second polypeptide chain comprises IL12b; the protein heterodimer further comprises IL2 or a functional fragment thereof, GMCSF or a functional fragment thereof, and one or more targeting moieties; and the IL2 or the functional fragment thereof is located in the first polypeptide chain or in the second polypeptide chain, the GMCSF or the functional fragment thereof is located in the first polypeptide chain or in the second polypeptide chain, and the one or more targeting moieties are each independently located in the first polypeptide chain or in the second polypeptide chain. 
     In some embodiments, the first polypeptide chain and the second polypeptide chain form the heterodimer through an interaction between the IL12a and the IL12b. 
     In some embodiments, the first polypeptide chain further comprises the IL2 or the functional fragment thereof, and the IL2 or the functional fragment thereof is directly or indirectly linked to the IL12a. 
     In some embodiments, in the first polypeptide chain of the protein heterodimer, the C-terminal of the IL2 or of the functional fragment thereof is directly or indirectly linked to the N-terminal of the IL12a or of the functional fragment thereof. 
     In some embodiments, in the first polypeptide chain of the protein heterodimer, the N-terminal of the IL2 or of the functional fragment thereof is directly or indirectly linked to the C-terminal of the IL12a or of the functional fragment thereof. 
     In some embodiments, the first polypeptide chain further comprises the GMCSF or the functional fragment thereof. 
     In some embodiments, in the first polypeptide chain of the protein heterodimer, the GMCSF or the functional fragment thereof is directly or indirectly linked to the IL12a or the functional fragment thereof. 
     In some embodiments, in the first polypeptide chain of the protein heterodimer, the N-terminal of the GMCSF or of the functional fragment thereof is directly or indirectly linked to the C-terminal of the IL12a or of the functional fragment thereof. 
     In some embodiments, in the first polypeptide chain of the protein heterodimer, the GMCSF or the functional fragment thereof is directly or indirectly linked to the IL2 or the functional fragment thereof. 
     In some embodiments, in the first polypeptide chain of the protein heterodimer, the N-terminal of the GMCSF or of the functional fragment thereof is directly or indirectly linked to the C-terminal of the IL2 or of the functional fragment thereof. 
     In some embodiments, the IL2 or the functional fragment thereof, the IL12a or the functional fragment thereof, and the GMCSF or the functional fragment thereof are sequentially comprised in the first polypeptide chain from the N-terminal to the C-terminal. 
     In some embodiments, the first polypeptide chain further comprises at least one of the targeting moieties. 
     In some embodiments, the at least one targeting moiety is directly or indirectly linked to the IL12a or the functional fragment thereof. 
     In some embodiments, the C-terminal of the at least one targeting moiety is directly or indirectly linked to the N-terminal of the IL2 or of the functional fragment thereof. 
     In some embodiments, the targeting moiety, the IL12a or the functional fragment thereof, the IL2 or the functional fragment thereof, and the GMCSF or the functional fragment thereof are sequentially comprised in the first polypeptide chain of the protein heterodimer from the N-terminal to the C-terminal. 
     In some embodiments, the second polypeptide chain further comprises at least one of the targeting moieties, and the at least one targeting moiety is directly or indirectly linked to the IL12b. 
     In some embodiments, the N-terminal of the at least one targeting moiety is directly or indirectly linked to the C-terminal of the IL12b or of the functional fragment thereof. 
     In some embodiments, the IL2 or the functional fragment thereof, the IL12a or the functional fragment thereof, and the GMCSF or the functional fragment thereof are sequentially comprised in the first polypeptide chain of the protein heterodimer from the N-terminal to the C-terminal; the IL12b or the functional fragment thereof and the targeting moiety. 
     In some embodiments, the targeting moiety, the IL12a or the functional fragment thereof, the IL2 or the functional fragment thereof, and the GMCSF or the functional fragment thereof are sequentially comprised in the first polypeptide chain of the protein heterodimer from the N-terminal to the C-terminal, and the IL12b or the functional fragment thereof and the targeting moiety are sequentially comprised in the second polypeptide chain from the N-terminal to the C-terminal. 
     In some embodiments, the IL12a or the functional fragment thereof, the IL12b or the functional fragment thereof, the IL2 or the functional fragment thereof, and the GMCSF or the functional fragment thereof are derived from mammal. 
     In some embodiments, the IL12a or the functional fragment thereof, the IL12b or the functional fragment thereof, the IL2 or the functional fragment thereof, and the GMCSF or the functional fragment thereof are derived from the same species. 
     In some embodiments, the same species is human. 
     In some embodiments, the protein heterodimer comprises a plurality of targeting moieties, which are the same. 
     In some embodiments, the protein heterodimer comprises a plurality of targeting moieties, at least two of which are different from each other. 
     In some embodiments, the one or more targeting moieties are capable of specifically binding to a tumor-associated antigen. 
     In some embodiments, the tumor-associated antigen is selected from the group consisting of: an EDB domain of fibronectin, an EDA domain of fibronectin, and/or a necrotic region. 
     In some embodiments, the one or more targeting moieties comprise an antibody or an antigen-binding fragment thereof. 
     In some embodiments, the antigen-binding fragment is selected from the group consisting of Fab, Fab′, F(ab′) 2 , F(ab) 2 , dAb, an isolated complementarity determining region CDR, Fv and scFv. 
     In some embodiments, the targeting moiety is scFv. 
     In some embodiments, the targeting moiety comprises an amino acid sequence as set forth in any one in the group consisting of: SEQ ID NOs: 1-3. 
     In some embodiments, the indirect linking comprises linking via a linker. 
     In some embodiments, the linker is a peptide linker. 
     In some embodiments, the one or more targeting moieties are linked to the IL12a and/or the IL12b via the linker. 
     In some embodiments, the linker comprises a thrombin cleavage site. 
     In some embodiments, the linker comprises an amino acid sequence as set forth in any one in the group consisting of SEQ ID NOs: 33-35. 
     In some embodiments, the first polypeptide chain comprises an amino acid sequence as set forth in any one in the group consisting of SEQ ID NOs: 17-23. 
     In some embodiments, the second polypeptide chain comprises an amino acid sequence as set forth in any one in the group consisting of SEQ ID NOs: 12-16. 
     In some embodiments, wherein,
     a) the first polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 17 and the second polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 12; and   b) the first polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 17 and the second polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 13; and   c) the first polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 17 and the second polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 14; and   d) the first polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 18 and the second polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 12; and   e) the first polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 19 and the second polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 13; and   f) the first polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 20 and the second polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 14; and   g) the first polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 21 and the second polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 15; and   h) the first polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 22 and the second polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 15; and   i) the first polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 23 and the second polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 16.   

     The present application provides a nucleic acid molecule or nucleic acid molecules encoding the protein heterodimer. 
     In some embodiments, the nucleic acid molecule comprises an amino acid sequence as set forth in any one in the group consisting of SEQ ID NOs: 24-32. 
     The present application provides a vector comprising the nucleic acid molecule. 
     The present application provides a cell expressing the encoding the protein heterodimer, or the nucleic acid molecule or the vector. 
     The present application provides a method for preparing the protein heterodimer, comprising the following step: culturing the cell. 
     The present application provides a pharmaceutical composition comprising the protein heterodimer. 
     The present application provides use of the protein heterodimer or the pharmaceutical composition in the preparation of a drug for preventing, alleviating or treating a tumor. 
     In some embodiments, the tumor comprises a solid tumor. 
     In some embodiments, the tumor comprises melanoma. 
     The present application provides a method for preventing, alleviating or treating a tumor, comprising administering the heterodimer and/or the pharmaceutical composition to a subject in need thereof. 
     Those skilled in the art can easily perceive other aspects and advantages of the present application from the detailed description below. The detailed description below only shows and describes exemplary embodiments of the present application. As will be appreciated by those skilled in the art, the content of the present application enables those skilled in the art to make changes to the disclosed specific embodiments without departing from the spirit and scope of the invention involved in the present application. Correspondingly, the accompanying drawings and the descriptions in the specification of the present application are merely for an exemplary rather than restrictive purpose. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The specific features of the present invention involved in the present application are listed in the appended claims. The characteristics and advantages of the present invention involved in the present application can be better understood by referring to the exemplary embodiments and the accompanying drawings described in detail below. The accompanying drawings are briefly illustrated as follows: 
         FIG. 1  shows the effect of regulating and expressing GFP on the growth of tumors in mice; 
         FIG. 2  shows the survival rate of mice in each group; 
         FIGS. 3-11  show the structures of protein heterodimers of the present application; 
         FIG. 12  shows the expression of a protein heterodimer mIL12bscF8-IL2IL12aGMCSF in an in vitro assay; 
         FIG. 13  shows the tumor regression in mice induced by a protein heterodimer mIL12bscF8-IL2IL12aGMCSF; 
         FIG. 14  shows the tumor regression in mice induced by a protein heterodimer mIL12bscF8-scF8IL12aIL2GMCSF; 
         FIG. 15  shows the successful expression of the protein heterodimer of the present application. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The embodiments of the invention of the present application will be illustrated by specific examples below. Those familiar with this technology can easily understand other advantages and effects of the invention of the present application from the content disclosed in the specification. 
     In the present application, the term “protein heterodimer” generally refers to a dimer structure composed of two different polypeptide chains. In the present application, the protein heterodimer may include a first polypeptide chain and a second polypeptide chain. The first polypeptide chain is different from the second polypeptide chain, wherein the first polypeptide chain may include IL12a, and the second polypeptide chain may include IL12b. 
     In the present application, the term “polypeptide chain” generally refers to a chain structure formed by linking a plurality of amino acids to each other and containing a plurality of peptide bonds. In the present application, the “polypeptide chain” may be a “first polypeptide chain” or a “second polypeptide chain”, wherein the first polypeptide chain is different from the second polypeptide chain. In the present application, the first polypeptide chain may include IL12a. In some cases, the first polypeptide chain may also include one or more in the group consisting of IL2 or a functional fragment thereof, GMCSF or a functional fragment thereof, and one or more targeting moieties. The second polypeptide chain may include IL12b. In some cases, the first polypeptide chain may also include one or more in the group consisting of: IL2 or a functional fragment thereof, GMCSF or a functional fragment thereof, and one or more targeting moieties. 
     In the present application, the term “targeting moiety” generally refers to a type of moiety that acts on certain special tissues and cells. For example, the targeting moiety is capable of specifically targeting a tumor-associated antigen. In the present application, the targeting moiety includes an antibody or an antigen-binding fragment thereof. 
     In the present application, the term “tumor-associated antigen” (TAA) generally refers to an antigen molecule existing on a tumor cell or a normal cell. The tumor-associated antigen may include: an embryonic protein, a glycoprotein antigen and a squamous cell antigen. The tumor-associated antigen may be selected from the group consisting of: an EDB domain of fibronectin, an EDA domain of fibronectin, and a necrotic region. 
     In the present application, the term “antigen-binding fragment” generally refers to a fragment having an antigen-binding activity. In the present application, the antigen-binding fragment may be selected from the group consisting of Fab, Fab′, F(ab′)2, F(ab)2, dAb, an isolated complementarity determining region (CDR), Fv and scFv. 
     In the present application, the term “antibody” is capable of specifically recognizing and/or neutralizing a polypeptide molecule of a specific antigen. A basic four-chain antibody unit is a heterotetrameric glycoprotein, which may be composed of two identical light chains and two identical heavy chains. In the case of IgG, each light chain may be linked to each heavy chain by a covalent disulfide bond, and two heavy chains may be linked to each other by a disulfide bond. Each heavy chain has a variable domain (VH) at the N-terminal, followed by three (for a and y types) or four (for p and F isotypes) constant domains (CH). 
     In the present application, the terms “IL12a”, “IL12b”, “IL2”, and “GMCSF” may be considered as “cytokines”. The “cytokine” generally refers to a class of small molecular proteins synthesized and secreted by stimulating immune cells (such as monocytes, macrophages, T cells, B cells, NK cells, etc.) and certain non-immune cells (such as endothelial cells, epidermal cells, fibroblasts, etc.), showing a broad spectrum of biological activities. The cytokine plays an important role in regulating inter-cellular interaction as well as cell growth and differentiation. In the present application, the cytokine may be one or more selected from the group consisting of: interleukin (IL) and a colony stimulating factor (CSF). The interleukin generally refers to a cytokine produced by lymphocytes, monocytes or other non-mononuclear cells. In the present application, the interleukin may be one or more selected from the group consisting of: IL12 and IL2. In the present application, the colony stimulating factor generally refers to a cytokine capable of stimulating different hematopoietic stem cells to form cell colonies in a semi-solid medium. In the present application, the colony stimulating factor may be a granulocyte macrophage colony stimulating factor (GMCSF). 
     In the present application, the term “IL12” generally refers to interleukin-12. IL12 may play an important role in regulating inter-cellular interaction, immune regulation, hematopoiesis, and inflammation. An IL12 molecule is generally a heterodimer typically including two subunits, namely, a p40 subunit (40 kd) and a p35 subunit (35 kd) respectively, which are linked together via a disulfide bond. In the present application, IL12 containing the p35 subunit (35 kd) may be represented as IL12a, and IL12 containing the p40 subunit (40 kd) may be represented as IL12b. For example, in murine-derived IL12 (mIL12), the p35 subunit may include an amino acid sequence as set forth in SEQ ID NO: 4, and the p40 subunit may include an amino acid sequence as set forth in SEQ ID NO: 5. For another example, in human-derived IL12 (hIL12), the p35 subunit may include an amino acid sequence as set forth in SEQ ID NO: 6, and the p40 subunit may include an amino acid sequence as set forth in SEQ ID NO: 7. 
     In the present application, the term “IL2” generally refers to interleukin-2. IL2 plays an important role in regulating inter-cellular interaction, immune regulation, hematopoiesis, and inflammation. For example, murine-derived IL2 (mIL2) may include an amino acid sequence as set forth in SEQ ID NO:8. For another example, human-derived IL2 (hIL2) may include an amino acid sequence as set forth in SEQ ID NO:9. 
     In the present application, the term “GMCSF” generally refers to a granulocyte macrophage colony stimulating factor. The GMCSF may have 4 α-helix bundle structures. For example, murine-derived GMCSF (mGMCSF) may include an amino acid sequence as set forth in SEQ ID NO:10. For another example, human-derived GMCSF (hGMCSF) may include an amino acid sequence as set forth in SEQ ID NO:11. 
     In the present application, the term “functional fragment” generally refers to a fragment that retains a certain specific function. For example, a functional fragment of IL2 refers to a fragment that retains the function of IL2. For example, the functional fragment of IL2 may be an IL2 fragment (GenBank: AAA59139.1), and in some cases, the functional fragment of IL2 may also be an IL2 fragment (GenBank: AAA59141.1). 
     In the present application, the term “directly link” is opposite to the term “indirectly link”, and the term “directly link” generally refers to a direct linkage. For example, the direct linkage may be a situation where substances (for example, the same or different cytokines and/or targeting moieties) are directly linked without a spacer. The spacer may be a linker. For example, the linker may be a peptide linker. The term “indirectly link” generally refers to a situation where substances (for example, the same or different cytokines and/or targeting moieties) are not directly linked. For example, the indirectly linking may be a situation where a linkage is performed via a spacer. For example, the C-terminal of IL2 or of the functional fragment thereof is directly linked to or indirectly linked via a linker to the N-terminal of IL12a or of the functional fragment thereof. For another example, the N-terminal of GMCSF or of the functional fragment thereof is directly linked to or indirectly linked via a linker to the C-terminal of IL12a or of the functional fragment thereof. 
     In the present application, the term “nucleic acid molecule” generally refers to a biological macromolecular compound polymerized from many nucleotides. In terms of different chemical compositions, the nucleic acid molecules may be classified into ribonucleic acids (RNAs for short) and deoxyribonucleic acids (DNAs for short). In the present application, the nucleic acid molecule encodes the protein heterodimer, and may include a nucleotide sequence as set forth in any one of SEQ ID NOs. 24-32. 
     In the present application, the term “vector” generally refers to a nucleic acid molecule capable of self-replication in a suitable host cell. It transfers an inserted nucleic acid molecule into and/or between host cells. The vector may include a vector mainly for inserting DNA or RNA into cells, a vector mainly for replicating DNA or RNA, and a vector mainly for expressing DNA or RNA transcription and/or translation. The vector may also include a carrier having a variety of the functions defined above. The vector may be a polynucleotide that may be transcribed and translated into a polypeptide when introduced into a suitable host cell. Generally, the vector may produce a desired expression product by culturing a suitable host cell containing the vector. 
     In the present application, the term “cell” generally refers to an individual cell, a cell line or a cell culture, which may contain or already contains the nucleic acid molecule described in the present application or the vector described in the present application, or is capable of expressing the protein heterodimer described in the present application. The cell may include a progeny of a single host cell. Due to natural, accidental or deliberate mutations, progeny cells and original parent cells may not necessarily be identical in terms of morphology or genome as long as they are capable of expressing the protein heterodimer described in the present application or containing the nucleic acid molecule or vector described in the present application. In the present application, a cell capable of expressing the protein heterodimer described in the present application may be obtained by transfecting a B16 (rtTA) tumor cell or a 293A cell with a virus of the expression vector. 
     In the present application, the term “tumor” generally refers to or describes a physiological condition of mammals, with the typical feature consisting in the disorder of cell proliferation or survival. For example, the tumor may include a solid tumor. For another example, the tumor may be melanoma. 
     In the present application, the term “solid tumor” generally refers to a tangible mass that may be diagnosed by clinical examination (such as X-ray photography, CT scanning, B-scan ultrasonography or palpation, etc.). In the present application, the solid tumor may be melanoma. 
     In the present application, the term “melanoma” generally refers to a pigmented nevus with malignant transformation. The melanoma may develop from a nevus with the properties of a junctional nevus or a compound nevus, with the manifestation of symptoms such as sudden incidence or rapid growth and continuously deepened color of a pigmented nevus. 
     Protein Heterodimer 
     In one aspect, the present application provides a protein heterodimer, comprising a first polypeptide chain and a second polypeptide chain different from the first polypeptide chain, wherein the first polypeptide chain comprises IL12a, and the second polypeptide chain comprises IL12b; the protein heterodimer further comprises IL2 or a functional fragment thereof, GMCSF or a functional fragment thereof, and one or more targeting moieties; and the IL2 or the functional fragment thereof is located in the first polypeptide chain or in the second polypeptide chain, the GMCSF or the functional fragment thereof is located in the first polypeptide chain or in the second polypeptide chain, and the one or more targeting moieties are each independently located in the first polypeptide chain or in the second polypeptide chain. 
     In the present application, the protein heterodimer may be a cytokine fusion protein, where the cytokines, i.e., two or more of IL12, IL2 and GMCSF, are fused together through the gene recombination technology. The protein heterodimer not only may have the unique biological activities of the constituent factors thereof, but also may exert biological functions that are not possessed by a single cytokine through the complementary and synergistic effects of biological activities, and may even produce some new structures and biological functions. 
     In the present application, the cytokine may be selected from the group consisting of: IL12, IL2 and GMCSF. 
     In the present application, the protein heterodimer may include one or more targeting moieties, wherein the targeting moieties may be the same or different. In the present application, the targeting moiety in the protein heterodimer includes an antibody or an antigen-binding fragment thereof, wherein the antigen-binding fragment may be selected from the group consisting of: Fab, Fab′, F(ab′)2, F(ab)2, dAb, an isolated complementarity determining region (CDR), Fv and scFv. 
     In the present application, the targeting moiety of the protein heterodimer may be selected from the group consisting of: L19V L , L19V H , F8V L , F8V H , NHS76V L , and NHS76V H . 
     In the present application, the targeting portion of the protein heterodimer may include a sequence as set forth in any one of SEQ ID NOs: 1-3. 
     In the present application, the indirect linking includes linking that may be performed via a linker. For example, the linker may be a linker peptide. In the present application, the linker may include an amino acid sequence as set forth in any one in the group consisting of: SEQ ID NOs: 33-35. 
     For example, the cytokines may be linked to each other via the linker. In the present application, the IL12a, IL12b, IL2 and GMCSF may be linked to one another via the linker peptide. For example, the linker peptide may include an amino acid sequence as set forth in SEQ ID NO. 34 or SEQ ID NO. 35. 
     For example, the cytokine and the targeting moiety may be linked by the linker. In the present application, the targeting moiety of the protein heterodimer may be linked to the IL12a, IL12b, IL2 and GMCSF via the linker peptide. For example, the linker peptide may include an amino acid sequence as set forth in any one of SEQ ID NOs: 33-35. 
     In the present application, the first polypeptide chain of the protein heterodimer further includes the IL2 or the functional fragment thereof, and the IL2 or the functional fragment thereof is directly or indirectly linked to the IL12a. 
     In the present application, the C-terminal of the IL2 or of the functional fragment thereof in the first polypeptide chain is directly or indirectly linked to the N-terminal of the IL12a or of the functional fragment thereof. 
     In the present application, the N-terminal of the IL2 or of the functional fragment thereof in the first polypeptide chain is directly or indirectly linked to the C-terminal of the IL12a or of the functional fragment thereof. 
     In the present application, the first polypeptide chain of the protein heterodimer further includes the GMCSF or the functional fragment thereof. 
     In the present application, the GMCSF or the functional fragment thereof in the first polypeptide chain is directly or indirectly linked to the IL12a or the functional fragment thereof. 
     In the present application, the N-terminal of the GMCSF or of the functional fragment thereof in the first polypeptide chain is directly or indirectly linked to the C-terminal of the IL12a or of the functional fragment thereof. 
     In the present application, the GMCSF or the functional fragment thereof in the first polypeptide chain is directly or indirectly linked to the IL2 or the functional fragment thereof. 
     In the present application, the N-terminal of the GMCSF or of the functional fragment thereof in the first polypeptide chain is directly or indirectly linked to the C-terminal of the IL2 or of the functional fragment thereof. 
     In the present application, the IL2 or the functional fragment thereof, the IL12a or the functional fragment thereof, and the GMCSF or the functional fragment thereof are sequentially included in the first polypeptide chain from the N-terminal to the C-terminal. 
     In the present application, the first polypeptide chain of the protein heterodimer further includes at least one of the targeting moieties. 
     In the present application, the at least one targeting moiety in the first polypeptide chain of the protein heterodimer is directly or indirectly linked to the IL12a or the functional fragment thereof. 
     In the present application, the C-terminal of the at least one targeting moiety in the first polypeptide chain of the protein heterodimer is directly or indirectly linked to the N-terminal of the IL2 or of the functional fragment thereof. 
     In the present application, the one or more targeting moieties, the IL12a or the functional fragment thereof, the IL2 or the functional fragment thereof, and the GMCSF or the functional fragment thereof are sequentially included in the first polypeptide chain of the protein heterodimer from the N-terminal to the C-terminal. 
     In the present application, the second polypeptide chain of the protein heterodimer further includes at least one of the targeting moieties, and the at least one targeting moiety is directly or indirectly linked to the IL12b. 
     In the present application, in the second polypeptide chain of the protein heterodimer, the N-terminal of the at least one targeting moiety is directly or indirectly linked to the C-terminal of the IL12b or of the functional fragment thereof. 
     In the present application, the IL2 or the functional fragment thereof, the IL12a or the functional fragment thereof, and the GMCSF or the functional fragment thereof are sequentially included in the first polypeptide chain of the protein heterodimer from the N-terminal to the C-terminal, and the IL12b or the functional fragment thereof and the targeting moiety are sequentially included in the second polypeptide chain from the N-terminal to the C-terminal. 
     In the present application, the targeting moiety, the IL12a or the functional fragment thereof, the IL2 or the functional fragment thereof, and the GMCSF or the functional fragment thereof are sequentially included in the first polypeptide chain of the protein heterodimer from the N-terminal to the C-terminal, and the IL12b or the functional fragment thereof and the targeting moiety are sequentially included in the second polypeptide chain from the N-terminal to the C-terminal. 
     In the present application, the IL12a or the functional fragment thereof, the IL12b or the functional fragment thereof, the IL2 or the functional fragment thereof, and the GMCSF or the functional fragment thereof in the protein heterodimer are derived from the same species. 
     In the present application, the IL12a or the functional fragment thereof, the IL12b or the functional fragment thereof, the IL2 or the functional fragment thereof, and the GMCSF or the functional fragment thereof in the protein heterodimer may be derived from human, and the human-derived IL12a, IL12b, IL2 and GMSCF may be written as hIL12a, hIL12b, hIL2 and hGMSCF. 
     In the present application, the IL12a or the functional fragment thereof, the IL12b or the functional fragment thereof, the IL2 or the functional fragment thereof, and the GMCSF or the functional fragment thereof in the protein heterodimer may be derived from mice, and the murine-derived IL12a, IL12b, IL2 and GMSCF may be written as mIL12a, mIL12b, mIL2 and mGMSCF. 
     In the present application, the protein heterodimer may include a plurality of targeting moieties, which are the same. 
     In the present application, the protein heterodimer may include a plurality of targeting moieties, at least two of which are different from each other. 
     In the present application, the first polypeptide chain may include the IL2 or the functional fragment thereof, and the second polypeptide chain may include the GMCSF or the functional fragment thereof. 
     In the present application, the first polypeptide chain may include the GMCSF or a functional fragment thereof; and the second polypeptide chain may include the IL2 or the functional fragment thereof. 
     In the present application, the first polypeptide chain may include a targeting moiety, which may be located at the N-terminal and/or the C-terminal of the first polypeptide chain; and the second polypeptide chain may include a targeting moiety, which may be located at the N-terminal and/or the C-terminal of the second polypeptide chain. 
     In the present application, the first polypeptide chain of the protein heterodimer may sequentially include the IL12a or the functional fragment thereof, the IL2 or the functional fragment thereof, and the GMCSF or the functional fragment thereof from the N-terminal to the C-terminal, wherein the C-terminal of the IL12a or of the functional fragment thereof is directly or indirectly linked to the N-terminal of the IL2 or of the functional fragment thereof, and the C-terminal of the IL2 or of the functional fragment thereof is directly or indirectly linked to the N-terminal of the GMCSF or of the functional fragment thereof. The first polypeptide chain of the protein heterodimer may sequentially include the targeting moiety, the IL12a or the functional fragment thereof, the IL2 or the functional fragment thereof, and the GMCSF or the functional fragment thereof from the N-terminal to the C-terminal, wherein the C-terminal of the targeting moiety is directly or indirectly linked to the N-terminal of the IL12a or of the functional fragment thereof; the C-terminal of the IL12a or of the functional fragment thereof is directly or indirectly linked to the N-terminal of the IL2 or of the functional fragment thereof; and the C-terminal of the IL2 or of the functional fragment thereof is directly or indirectly linked to the N-terminal of the GMCSF or of the functional fragment thereof. 
     In the present application, the first polypeptide chain of the protein heterodimer may sequentially include the IL2 or the functional fragment thereof, the IL12a or the functional fragment thereof, and the GMCSF or the functional fragment thereof from the N-terminal to the C-terminal, wherein the C-terminal of the IL2 or of the functional fragment thereof is directly or indirectly linked to the N-terminal of the IL12a or of the functional fragment thereof, and the C-terminal of the IL12a or of the functional fragment thereof is directly or indirectly linked to the N-terminal of the GMCSF or of the functional fragment thereof. 
     In the present application, the first polypeptide chain of the protein heterodimer may sequentially include the IL12b or the functional fragment thereof and the targeting moiety from the N-terminal to the C-terminal. Herein, the C-terminal of the IL12b or of the functional fragment thereof is directly or indirectly linked to the N-terminal of the targeting moiety. 
     In the present application, the first polypeptide chain of the protein heterodimer may sequentially include the targeting moiety, the IL12a or the functional fragment thereof, the IL2 or the functional fragment thereof, and the GMCSF or the functional fragment thereof from the N-terminal to the C-terminal; and the second polypeptide chain may sequentially include the IL12b or the functional fragment thereof and the targeting moiety from the N-terminal to the C-terminal. The first polypeptide chain of the protein heterodimer may sequentially include the IL2 or the functional fragment thereof, the IL12a or the functional fragment thereof, and the GMCSF or the functional fragment thereof from the N-terminal to the C-terminal; and the second polypeptide chain may sequentially include the IL12b or the functional fragment thereof and the targeting moiety from the N-terminal to the C-terminal. 
     In the present application, in the first polypeptide chain of the protein heterodimer, the C-terminal of the targeting moiety may be directly or indirectly linked to the N-terminal of the IL12a or of the functional fragment thereof, the C-terminal of the IL12a or of the functional fragment thereof may be directly or indirectly linked to the N-terminal of the IL2 or of the functional fragment thereof, the C-terminal of the IL2 or of the functional fragment thereof may be directly or indirectly linked to the N-terminal of the GMCSF or of the functional fragment thereof, and in the second polypeptide chain, the C-terminal of the IL12b or of the functional fragment thereof may be directly or indirectly linked to the N-terminal of the targeting moiety. The C-terminal of the IL2 or of the functional fragment thereof may be directly or indirectly linked to the N-terminal of the IL12a or of the functional fragment thereof, the C-terminal of the IL12a or of the functional fragment thereof may be directly or indirectly linked to the N-terminal of the GMCSF or of the functional fragment thereof, and in the second polypeptide chain, the C-terminal of the IL12b or of the functional fragment thereof may be directly or indirectly linked to the N-terminal of the targeting moiety. 
     The IL12a and IL12b per se may be covalently bonded via disulfide bond. In the present application, the first polypeptide chain and the second polypeptide chain may be bonded by the disulfide bond between the IL12a and the IL12b to form the protein molecule. In some embodiments, a nucleotide sequence encoding a self-cleaving peptide may be included between a nucleotide sequence encoding the first polypeptide chain and a nucleotide sequence encoding the second polypeptide chain. For example, when the expression vector containing the nucleotide sequence above is transcribed and translated, the position of the self-cleavage peptide will be cut to form the protein heterodimer that includes the first polypeptide chain and the second polypeptide chain and is formed via the disulfide bond. 
     In the present application, the targeting moiety may be selected from: L19V L  (with an amino acid sequence that may be as set forth in SEQ ID NO. 36), L19V H  (with an amino acid sequence that may be as set forth in SEQ ID NO. 37), F8V L  (with an amino acid sequence that may be as set forth in SEQ ID NO. 38), F8V H  (with an amino acid sequence that may be as set forth in SEQ ID NO. 39), NHS76V L  (with an amino acid sequence that may be as set forth in SEQ ID NO. 40), and NHS76V H  (with an amino acid sequence that may be as set forth in SEQ ID NO. 41). 
     For example, in the protein heterodimer, the C-terminal of the IL12b may be fused to the N-terminal of the L19V H  and the C-terminal of the L19V H  may be fused to the N-terminal of the L19V L  to form a second polypeptide chain, and the C-terminal of the IL2 may be fused to the N-terminal of the IL12a and the C-terminal of the IL12a may be fused to the N-terminal of the GMCSF to form a first polypeptide chain, thereby forming a protein heterodimer IL12b-L19V H -L19V L -IL2-IL12a-GMCSF. 
     For example, in the protein heterodimer, the C-terminal of the IL12b may be fused to the N-terminal of the F8V H  and the C-terminal of the F8V H  may be fused to the N-terminal of the L19V L  to form a second polypeptide chain, and the C-terminal of the IL2 may be fused to the N-terminal of the IL12a and the C-terminal of the IL12a may be fused to the N-terminal of the GMCSF to form a first polypeptide chain, thereby forming a protein heterodimer IL12b-F8V H -F8V L -IL2-IL12a-GMCSF. 
     For example, in the protein heterodimer, the C-terminal of the IL12b may be fused to the N-terminal of the NHS76V 1  and the C-terminal of the NHS76V 1  may be fused to a N-terminal of the NHS76VL to form a second polypeptide chain, and the C-terminal of the IL2 may be fused to the N-terminal of the IL12a and the C-terminal of the IL12a may be fused to the N-terminal of the GMCSF to form a first polypeptide chain, thereby forming a protein heterodimer IL112b-NHS76V H -NHS76V L -IL2-IL12a-GMCSF. 
     For example, in the protein heterodimer, the C-terminal of the IL12b may be fused to the N-terminal of the L19V H  and the C-terminal of the L19V H  may be fused to the N-terminal of the L19V L  to form a second polypeptide chain; and the C-terminal of the L19V H  may be fused to the N-terminal of the L19V L , the C-terminal of the L19V L  may be fused to the N-terminal of the IL2, the C-terminal of IL2 may be fused to the N-terminal of IL12a, and the C-terminal of the IL12a may be fused to the N terminal of GMCSF to form a first polypeptide chain, thereby forming a protein heterodimer IL12b-L19V H -L19V L -L19V H -L19V L -IL2-IL12a-GMCSF. 
     For example, in the protein heterodimer, the C-terminal of the IL12b may be fused to the N-terminal of the F8V H , the C-terminal of the F8V H  may be fused to the N-terminal of the F8V L  to form a second polypeptide chain; and the C-terminal of the F8V H  may be fused to the N-terminal of the F8V L , the C-terminal of the F8V L  may be fused to the N-terminal of the IL2, the C-terminal of the IL2 may be fused to the N-terminal of the IL12a, and the C-terminal of the IL12a may be fused to the N-terminal of the GMCSF to form a first polypeptide chain, thereby forming a protein heterodimer IL12b-F8V H -F8V L -F8V H -F8V L -IL2-IL12a-GMCSF. 
     For example, in the protein heterodimer, the C-terminal of the IL12b may be fused to the N-terminal of the NHS76V H , and the C-terminal of the NHS76V H  may be fused to the N-terminal of the NHS76V L  to form a second polypeptide chain; and the C-terminal of the NHS76V H  may be fused to the N-terminal of the NHS76V L , the C-terminal of the NHS76V L  may be fused to the N-terminal of the IL2, the C-terminal of the IL2 may be fused to the N-terminal of the IL12a, and the C-terminal of the IL12a may be fused to the N-terminal of the GMCSF to form a first polypeptide chain, thereby forming a protein heterodimer IL12b-NHS76V H -NHS76V L -NHS76V H -NHS76V L -IL2-IL12a-GMCSF. 
     In the present application, the first polypeptide chain may include a sequence as set forth in any one of SEQ ID NOs. 17-23. 
     In the present application, the second polypeptide chain may include a sequence as set forth in any one of SEQ ID NOs. 12-16. 
     In the present application, the protein heterodimer may include a sequence as set forth in any one of SEQ ID NOs. 12-23. 
     For example, in the protein heterodimer, the C-terminal of the mIL12b may be fused to the N-terminal of the L19V H , and the C-terminal of the L19V H  may be fused to the N-terminal of the L19V L  to form a second polypeptide chain (with an amino acid sequence that may be as set forth in SEQ ID NO 12); and the C-terminal of the mIL2 may be fused to the N-terminal of the mIL12a, and the C-terminal of the mIL12a may be fused to the N-terminal of the mGMCSF to form a first polypeptide chain (with an amino acid sequence that may be as set forth in SEQ ID NO. 17), thereby forming a protein heterodimer of mIL12b-L19V H -L19V L -mIL2-mIL12a-mGMCSF. 
     For example, in the protein heterodimer, the C-terminal of the mIL12b may be fused to the N-terminal of the F8V H , and the C-terminal of the F8V H  may be fused to the N-terminal of the F8V L  to form a second polypeptide chain (with an amino acid sequence that may be as set forth in SEQ ID NO. 13); and the C-terminal of the mIL2 may be fused to the N-terminal of the mIL12a, and the C-terminal of the mIL12a may be fused to the N-terminal of the mGMCSF to form a first polypeptide chain (with an amino acid sequence that may be as set forth in SEQ ID NO. 17), thereby forming a protein heterodimer mIL12b-F8V H -F8V L -mIL2-mIL12a-mGMCSF. 
     For example, in the protein molecule, the C-terminal of the mIL12b may be fused to the N-terminal of the NHS76V H , and the C-terminal of the NHS76V H  may be fused to the N-terminal of the NHS76V L  to form a second polypeptide chain (with an amino acid sequence that may be as set forth in SEQ ID NO. 14); and the C-terminal of the mIL2 may be fused to the N-terminal of the mIL12a, and the C-terminal of the mIL12a may be fused to the N-terminal of the mGMCSF to form a first polypeptide chain (with an amino acid sequence that may be as set forth in SEQ ID NO. 17), thereby forming a protein heterodimer mIL12b-NHS76V H -NHS76V L -mIL2-mIL12a-mGMCSF. 
     For example, in the protein molecule, the C-terminal of the mIL12b may be fused to the N-terminal of the L19V H , and the C-terminal of the L19V H  may be fused to the N-terminal of the L19V L  to form a second polypeptide chain (with an amino acid sequence that may be as set forth in SEQ ID NO. 12), and the C-terminal of the L19V H  may be fused to the N-terminal of the L19V L , the C-terminal of the L19V L  may be fused to the N-terminal of the mIL12a, the C-terminal of the mIL12a may be fused to the N-terminal of the mIL2, and the C-terminal of the mIL2 may be fused to the N-terminal of the mGMCSF to form a first polypeptide chain (with an amino acid sequence that may be as set forth in SEQ ID NO. 18), thereby forming a protein heterodimer mIL12b-L19V H -L19V L -L19V H -L19V L -mIL12a-mIL2-mGMCSF. 
     For example, in the protein molecule, the C-terminal of the mIL12b may be fused to the N-terminal of the F8V H , and the C-terminal of the F8V H  may be fused to the N-terminal of the F8V L  to form a second polypeptide chain (with an amino acid sequence that may be as set forth in SEQ ID NO. 13); and the C-terminal of the F8V H  may be fused to the N-terminal of the F8V L , the C-terminal of the F8V L  may be fused to the N-terminal of the mIL12a, the C-terminal of the mIL12a may be fused to the N-terminal of the mIL2, and the C-terminal of the mIL2 may be fused to the N-terminal of the mGMCSF to form a first polypeptide chain (with an amino acid sequence that may be as set forth in SEQ ID NO. 19), thereby forming a protein heterodimer m L12b-F8V H -F8V L -F8V H -F8V L -mIL12a-mIL2-mGMCSF. 
     For example, in the protein molecule, the C-terminal of the mIL12b may be fused to the N-terminal of the NHS76V H , and the C-terminal of the NHS76V H  may be fused to the N-terminal of the NHS76V L  to form a second polypeptide chain (with an amino acid sequence that may be as set forth in SEQ ID NO. 14); and the C-terminal of the NHS76V H  may be fused to the N-terminal of the NHS76V L , the C-terminal of the NHS76V L  may be fused to the N-terminal of the mIL12a, the C-terminal of the mIL12a may be fused to the N-terminal of the mIL2, and the C-terminal of the mIL2 may be fused to the N-terminal of the GMCSF to form a first polypeptide chain (with an amino acid sequence that may be as set forth in SEQ ID NO. 20), thereby forming a protein heterodimer mIL12b-NHS76V H -NHS76V L -NHS76V H -NHS76V L -mIL12a-mIL2-mGMCSF. 
     For example, in the protein molecule, the C-terminal of the hIL12b may be fused to the N-terminal of the F8V H , and the C-terminal of the F8V H  may be fused to the N-terminal of the F8V L  to form a second polypeptide chain (with an amino acid sequence that may be as set forth in SEQ ID NO. 15); and the C-terminal of the hIL2 may be fused to the N-terminal of the hIL12a, and the C-terminal of the hIL12a may be fused to the N-terminal of the hGMCSF to form a first polypeptide chain (with an amino acid sequence that may be as set forth in SEQ ID NO. 21), thereby forming a protein heterodimer hIL12b-F8V H -F8V L -hIL2-hIL12a-hGMCSF. 
     For example, in the protein molecule, the C-terminal of the hIL12b may be fused to the N-terminal of the F8V H , and the C-terminal of the F8V H  may be fused to the N-terminal of the F8V L , to form a second polypeptide chain (with an amino acid sequence that may be as set forth in SEQ ID NO. 15); and the C-terminal of the F8V H  may be fused to the N-terminal of the F8V L , the C-terminal of the F8V L  may be fused to the N-terminal of the hIL12a, the C-terminal of the hIL12a may be fused to the N-terminal of the hIL2, and the C-terminal of the hIL2 may be fused to the N-terminal of the hGMCSF to form a first polypeptide chain (with an amino acid sequence that may be as set forth in SEQ ID NO. 22), thereby forming a protein heterodimer hIL12b-F8V H -F8V L -F8V H -F8V L -hIL12a-hIL2-hGMCSF. 
     For example, in the protein molecule, the C-terminal of the hIL12b may be fused to the N-terminal of the NHS76V H , and the C-terminal of the NHS76V H  may be fused to the N-terminal of the NHS76V L  to form a second polypeptide chain (with an amino acid sequence that may be as set forth in SEQ ID NO. 16); and the C-terminal of the NHS76V H  may be fused to the N-terminal of the NHS76V L , the C-terminal of the NHS76V L  may be fused to the N-terminal of the hIL12a, the C-terminal of the hIL12a may be fused to the N-terminal of the hIL2, and the C-terminal of the hIL2 may be fused to the N-terminal of the hGMCSF to form a first polypeptide chain (with an amino acid sequence that may be as set forth in SEQ ID NO. 23), thereby forming a protein heterodimer hIL12b-NHS76V H -NHS76V L -NHS76V H -NHS76V L -hIL12a-hIL2-hGMCSF. 
     In the present application, the mIL12b-L19V H -L19V L -mIL2-mIL12a-mGMCSF, mIL12b-F8V H -F8V L -mIL2-mIL12a-mGMCSF, mIL12b-NHS76V H -NHS76V L -mIL2-mIL12a-mGMCSF, mIL12b-L19V H -L19V L -L19V H -L19V L -mIL12a-mIL2-mGMCSF, mIL12b-F8V H -F8V L -F8V H -F8V L -mIL12a-mIL2-mGMCSF, mIL12b-NHS76V H -NHS76V L -NHS76V H -NHS76V L -mIL12a-mIL2-mGMCSF, hIL12b-F8V H -F8V L -hIL2-hIL12a-hGMCSF, hIL12b-F8V H -F8V L -F8V H -F8V L -hIL12a-hIL2-hGMCSF and hIL12b-NHS76V H -NHS76V L -NHS76V H -NHS76V L -hIL12a-hIL2-hGMCSF may be sequentially referred to as mIL12bscL19-IL2IL12aGMCSF, mIL12bscF8-IL2IL12aGMCSF, mIL12bscNHS76-IL2IL12aGMCSF, mIL12bscL19-scL19IL12aIL2GMCSF, mIL12bscF8-F8IL12aIL2GMCSF, mIL12bscNHS76-scNHS76IL12aIL2GMCSF, hIL12bscF8-IL2IL12aGMCSF, hIL12bscF8-F8IL12aIL2GMCSF and hIL12bscNHS76-scNHS76IL12aIL2GMCSF for short, respectively. 
     The protein, polypeptide, and/or amino acid sequence involved in the present application should also be understood to include at least the following range: a variant or homologue that has the same or similar functions as said protein or polypeptide. 
     In the present application, the variant may be a protein or polypeptide formed by substituting, deleting or adding one or more amino acids in an amino acid sequence of said protein and/or polypeptide (for example, the protein molecule). For example, the functional variant may include a protein or polypeptide with amino acid changes induced by substituting, deleting, and/or inserting at least one amino acid, for example, 1-30, 1-20, or 1-10 amino acids, and for another example, 1, 2, 3, 4, or 5 amino acids. The functional variant may substantially maintain the biological properties of said protein or polypeptide before the changes (for example, substitution, deletion, or addition). For example, the functional variant may maintain at least 60%, 70%, 80%, 90%, or 100% of the biological activities of said protein or polypeptide before the changes. 
     In the present application, the homologue may be a protein or polypeptide that has at least about 80% (for example, at least about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99% or higher) sequence homology with the amino acid sequence of said protein and/or polypeptide (for example, the protein molecule). 
     In the present application, the homology generally refers to the similarity, resemblance or association between two or more sequences. The “percentage of sequence homology” may be calculated in the following way: comparing two sequences to be aligned in a comparison window, determining in the two sequences the number of positions at which identical nucleic acid bases (for example, A, T, C, G) or identical amino acid residues (for example, Ala, Pro, Ser, Thr, Gly, Val, Leu, Ile, Phe, Tyr, Trp, Lys, Arg, His, Asp, Glu, Asn, Gln, Cys, and Met) exist to acquire the number of matching positions; and dividing the number of matching positions by the total number of positions in the comparison window (i.e., the window size), and multiplying a result by 100 to produce the sequence homology percentage. The alignment for determining the sequence homology percentage may be achieved in a variety of ways known in the art, for example, by using publicly available computer software such as BLAST, BLAST-2, ALIGN or Megalign (DNASTAR) software. Those skilled in the art may determine appropriate parameters for sequence alignment, including any algorithm required to implement the maximum alignment undergoing comparison, within a full-length sequence range or within a target sequence region. The homology may also be determined by the following methods: FASTA and BLAST. For the description of the FASTA algorithm, a reference may be made to W. R. Pearson and D. J. Lipman, “Improved Tools for Biological Sequence Comparison”, Proc. Natl. Acad. Sci.), 85: 2444-2448, 1988; and D. J. Lipman and W. R. Pearson, “Rapid and Sensitive Protein Similarity Searches”, Science, 227: 1435-1441, 1989. For the description of the BLAST algorithm, a reference may be made to S. Altschul, W. Gish, W. Miller, E. W. Myers and D. Lipman, “Basic Local Alignment Search Tool”, J. Mol. Biol., 215: 403-410, 1990. 
     In another aspect, the present application provides a nucleic acid molecule encoding the defined protein molecule. 
     In the present application, the nucleic acid molecule may be selected from any one of nucleotide sequences as set forth in the group consisting of: SEQ ID NOs. 24-32. 
     In another aspect, the present application provides a vector including the defined nucleic acid molecule. 
     In the present application, methods for constructing vectors and plasmids, such as methods for inserting genes encoding proteins into vectors and plasmids or methods for introducing plasmids into host cells, are well known to those ordinarily skilled in the art and have been described in many publications, including Sambrook, J., Fritsch, E. F. and Maniais, T. (1989) Molecular Cloning: A Laboratory Manual, 2nd edition, Cold spring Harbor Laboratory Press. 
     In another aspect, the present application provides a cell expressing said protein molecule, or containing said nucleic acid molecule, or containing said vector. 
     In the present application, the cell may be used to treat a tumor. In the present application, the tumor may include a solid tumor. For example, the tumor may include melanoma. 
     In another aspect, the present application provides a method for preparing said protein molecule, including the following step: culturing said cell. 
     In the present application, the method may be performed in a situation that the protein molecule may be expressed. 
     In another aspect, the present application provides a pharmaceutical composition including said protein molecule. 
     In the present application, the pharmaceutical composition may also include a pharmaceutically acceptable carrier. For example, the pharmaceutically acceptable carrier may include a buffer, an antioxidant, a preservative, a low molecular weight polypeptide, a protein, a hydrophilic polymer, an amino acid, a sugar, a chelating agent, a counterion, a metal complex and/or a non-ionic surfactant, etc. For example, the pharmaceutically acceptable carrier may include an excipient. For example, the excipient may be selected from the group consisting of: starch, dextrin, sucrose, lactose, magnesium stearate, calcium sulfate, carboxymethyl, talcum powder, calcium alginate gel, chitosan and nano microspheres, etc. For example, the pharmaceutically acceptable carrier may also be selected from the group consisting of: a pH regulator, an osmotic pressure regulator, a solubilizer and an bacteriostatic agent. 
     In the present application, the pharmaceutical composition may be formulated for oral administration, intravenous administration, intramuscular administration, in situ administration at a tumor site, inhalation, rectal administration, vaginal administration, transdermal administration, or administration via a subcutaneous depot. 
     In the present application, the pharmaceutical composition may be used to inhibit tumor growth. For example, the pharmaceutical composition of the present application may inhibit or delay the development or progression of a disease, may reduce the size of a tumor (or even substantially eliminate the tumor) by promoting the expression of cytokines, and/or may alleviate and/or stabilize a disease state. 
     In the present application, the pharmaceutical composition may include a therapeutically effective amount of the protein molecule, the nucleic acid molecule, the vector and/or the host cell. therapeutically effective amount is a dose required to prevent and/or treat (at least partially treat) a disorder or condition (such as cancer) and/or any complications thereof in a subject suffering from or at risk of developing the disorder or condition. 
     In another aspect, the present application provides uses of the protein molecule, the pharmaceutical composition, the nucleic acid molecule, the carrier and/or the cell in the preparation of an anti-tumor drug. 
     The present application provides the protein molecule, the pharmaceutical composition, the nucleic acid molecule, the vector and/or the cell for treating tumors. 
     The present application provides a method for alleviating or treating a tumor, which may include administering the protein molecule, the pharmaceutical composition, the nucleic acid molecule, the vector and/or the cell to a subject in need thereof. 
     In the present application, methods for administration may include oral administration, intravenous administration, intramuscular administration, in situ administration at a tumor site, inhalation, rectal administration, vaginal administration, transdermal administration or administration via a subcutaneous depot. 
     In the present application, the tumor may include a solid tumor. For example, the tumor may include melanoma. 
     The present application further comprises the following embodiments.
     1. A protein heterodimer, comprising a first polypeptide chain and a second polypeptide chain different from the first polypeptide chain, wherein the first polypeptide chain comprises IL12a, and the second polypeptide chain comprises IL12b;
       the protein heterodimer further comprises IL2 or a functional fragment thereof, GMCSF or a functional fragment thereof, and one or more targeting moieties; and   the IL2 or the functional fragment thereof is located in the first polypeptide chain or in the second polypeptide chain, the GMCSF or the functional fragment thereof is located in the first polypeptide chain or in the second polypeptide chain, and the one or more targeting moieties are each independently located in the first polypeptide chain or in the second polypeptide chain.   
       2. The protein heterodimer according to Embodiment 1, wherein the first polypeptide chain and the second polypeptide chain form the heterodimer through an interaction between the IL12a and the IL12b.   3. The protein heterodimer according to any one of Embodiments 1-2, wherein the first polypeptide chain further comprises the IL2 or the functional fragment thereof, and the IL2 or the functional fragment thereof is directly or indirectly linked to the IL12a.   4. The protein heterodimer according to any one of Embodiments 1-3, wherein in the first polypeptide chain, the C-terminal of the IL2 or of the functional fragment thereof is directly or indirectly linked to the N-terminal of the IL12a or of the functional fragment thereof.   5. The protein heterodimer according to any one of Embodiments 1-3, wherein in the first polypeptide chain, the N-terminal of the IL2 or of the functional fragment thereof is directly or indirectly linked to the C-terminal of the IL12a or of the functional fragment thereof.   6. The protein heterodimer according to any one of Embodiments 1-5, wherein the first polypeptide chain further comprises the GMCSF or the functional fragment thereof.   7. The protein heterodimer according to any one of Embodiments 1-6, wherein in the first polypeptide chain, the GMCSF or the functional fragment thereof is directly or indirectly linked to the IL12a or the functional fragment thereof.   8. The protein heterodimer according to Embodiment 7, wherein in the first polypeptide chain, the N-terminal of the GMCSF or of the functional fragment thereof is directly or indirectly linked to the C-terminal of the IL12a or of the functional fragment thereof.   9. The protein heterodimer according to any one of Embodiments 1-6, wherein in the first polypeptide chain, the GMCSF or the functional fragment thereof is directly or indirectly linked to the IL2 or the functional fragment thereof.   10. The protein heterodimer according to Embodiment 9, wherein in the first polypeptide chain, the N-terminal of the GMCSF or of the functional fragment thereof is directly or indirectly linked to the C-terminal of the IL2 or of the functional fragment thereof.   11. The protein heterodimer according to any one of Embodiments 1-10, wherein the IL2 or the functional fragment thereof, the IL12a or the functional fragment thereof, and the GMCSF or the functional fragment thereof are sequentially comprised in the first polypeptide chain from the N-terminal to the C-terminal.   12. The protein heterodimer according to any one of Embodiments 1-11, wherein the first polypeptide chain further comprises at least one of the targeting moieties.   13. The protein heterodimer according to any Embodiment 12, wherein in the first polypeptide chain, the at least one targeting moiety is directly or indirectly linked to the IL12a or the functional fragment thereof.   14. The protein heterodimer according to any one of Embodiments 12-13, wherein the C-terminal of the at least one targeting moiety is directly or indirectly linked to the N-terminal of the IL2 or of the functional fragment thereof.   15. The protein heterodimer according to any one of Embodiments 12-14, wherein the one or more targeting moieties, the IL12a or the functional fragment thereof, the IL2 or the functional fragment thereof, and the GMCSF or the functional fragment thereof are sequentially comprised in the first polypeptide chain from the N-terminal to the C-terminal.   16. The protein heterodimer according to any one of Embodiments 1-15, wherein the second polypeptide chain further comprises at least one of the one or more targeting moieties, and the at least one targeting moiety is directly or indirectly linked to the IL12b.   17. The protein heterodimer according to any one of Embodiment 16, wherein the N-terminal of the at least one targeting moiety is directly or indirectly linked to the C-terminal of the IL12b or of the functional fragment thereof.   18. The protein heterodimer according to any one of Embodiments 1-17, wherein the IL2 or the functional fragment thereof, the IL12a or the functional fragment thereof, and the GMCSF or the functional fragment thereof are sequentially comprised in the first polypeptide chain from the N-terminal to the C-terminal, and the IL12b or the functional fragment thereof and the one or more targeting moieties are sequentially comprised in the second polypeptide chain from the N-terminal to the C-terminal, or,   19. The protein heterodimer according to any one of Embodiments 1-17, wherein the IL2 or the functional fragment thereof, the IL12a or the functional fragment thereof, and the GMCSF or the functional fragment thereof are sequentially comprised in the first polypeptide chain from the N-terminal to the C-terminal, and the IL12b or the functional fragment thereof and the one or more targeting moieties are sequentially comprised in the second polypeptide chain from the N-terminal to the C-terminal.   20. The protein heterodimer according to any one of Embodiments 1-19, wherein the IL12a or the functional fragment thereof, the IL12b or the functional fragment thereof, the IL2 or the functional fragment thereof, and the GMCSF or the functional fragment thereof are derived from mammal.   21. The protein heterodimer according to any one of Embodiments 1-20, wherein the IL12a or the functional fragment thereof, the IL12b or the functional fragment thereof, the IL2 or the functional fragment thereof, and the GMCSF or the functional fragment thereof are derived from the same species.   22. The protein heterodimer according to Embodiment 21, wherein the same species is human.   23. The protein heterodimer according to any one of Embodiments 1-22 wherein the protein heterodimer comprises a plurality of targeting moieties, which are the same.   24. The protein heterodimer according to any one of Embodiments 1-22, wherein the protein heterodimer comprises a plurality of targeting moieties, at least two of which are different from each other.   25. The protein heterodimer according to any one of Embodiments 1-24, wherein the one or more targeting moieties are capable of specifically targeting a tumor-associated antigen.   26. The protein heterodimer according to Embodiment 25, wherein the tumor-associated antigen is selected from the group consisting of an EDB domain of fibronectin, an EDA domain of fibronectin, and/or a necrotic region.   27. The protein heterodimer according to any one of Embodiments 1-26, wherein the one or more targeting moieties comprise an antibody or an antigen-binding fragment thereof.   28. The protein heterodimer according to Embodiment 27, wherein the antigen-binding fragment is selected from the group consisting of. Fab, Fab′, F(ab′)2, F(ab)2, dAb, an isolated complementarity determining region CDR, Fv and scFv.   29. The protein heterodimer according to any one of Embodiments 1-28, wherein the one or more targeting moieties are scFV   30. The protein heterodimer according to any one of Embodiments 1-29, wherein the one or more targeting moieties comprise an amino acid sequence as set forth in any one in the group consisting of: SEQ ID NOs: 1-3.   31. The protein heterodimer according to any one of Embodiments 3-30, wherein the indirect linking comprises linking via a linker.   32. The protein heterodimer according to Embodiment 31, wherein the linker is a peptide linker.   33. The protein heterodimer according to any one of Embodiments 31-32, wherein the one or more targeting moieties are linked to the IL12a and/or the IL12b via the linker.   34. The protein heterodimer according to Embodiment 33, wherein the linker comprises a thrombin cleavage site.   35. The protein heterodimer according to any one of Embodiments 31-34, wherein the linker comprises an amino acid sequence as set forth in any one in the group consisting of: SEQ ID NOs: 33-35.   36. The protein heterodimer according to any one of Embodiments 1-35, wherein the first polypeptide chain comprises an amino acid sequence as set forth in any one in the group consisting of: SEQ ID NOs: 17-23.   37. The protein heterodimer according to any one of Embodiments 1-36, wherein the second polypeptide chain comprises an amino acid sequence as set forth in any one in the group consisting of: SEQ ID NOs: 12-16.   38. The protein heterodimer according to any one of Embodiments 1-37, wherein   a) the first polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 17 and the second polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 12; and   b) the first polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 17 and the second polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 13; and   c) the first polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 17 and the second polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 14; and   d) the first polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 18 and the second polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 12; and   e) the first polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 19 and the second polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 13; and   f) the first polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 20 and the second polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 14; and   g) the first polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 21 and the second polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 15; and   h) the first polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 22 and the second polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 15; and   i) the first polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 23 and the second polypeptide chain comprises an amino acid sequence as set forth in SEQ ID NO: 16.   39. A nucleic acid molecule or nucleic acid molecules encoding the protein heterodimer according to any one of Embodiments 1-38.   40. The nucleic acid molecule according to Embodiment 39, comprising an amino acid sequence as set forth in any one in the group consisting of: SEQ ID NOs: 24-32.   41. A vector, comprising the nucleotide molecule according to any one of Embodiments 39-40.   42. A cell expressing the protein heterodimer according to any one of nucleic acid molecules 1-38, or comprising the nucleic acid molecule or nucleic acid molecules according to Embodiments 39-40, or the vector according to Embodiment 41.   43. A method for preparing the protein heterodimer according to any one of Embodiments 1-38, comprising the following step: culturing the cell according to Embodiment 42.   44. A pharmaceutical composition, comprising the protein heterodimer according to any one of Embodiments 1-38.   45. Use of the heterodimer according to any one of Embodiments 1-38 and/or the pharmaceutical composition according to Embodiment 44 in the preparation of a drug for preventing, alleviating or treating a tumor.   46. The use according to Embodiment 45, wherein the tumor comprises a solid tumor.   47. The use according to any one of Embodiments 45-46, wherein the tumor comprises melanoma.   

     Not wishing to be bound by any particular theory, the following examples are merely to illustrate the fusion protein, preparation methods and uses etc. according to the present application, and are not intended to limit the scope of the present invention. 
     EXAMPLES 
     Example 1 Preparation of Tumor Cells Expressing Regulatable Proteins 
     1.1 Construction of First Expression Vector pLentis-CMV-rtTA-IRES-Bsd 
     A DNA sequence or rtTA (GenBank: ALK44378.1) with sites BamHI and EcoRI at both ends were synthesized, and a synthesized product was linked to a pUC57 vector. The pUC57 vector linked to the rtTA was enzyme-digested, with an enzyme digestion system as follows: 6 μg of pUC57 vector plasmid linked to the rtTA, 4 μl of enzyme-digestion buffer, 1 μl of BamHI, and 1 μl of EcoRI were added with water to a total volume of 40 μl, and let stand at 37° C. for 12 hours. An EP tube was taken out and added with 4.4 μl of 10× loading buffer; electrophoresis was performed by using 1% agarose gel; and after the electrophoresis, a rtTA fragment was recovered for later use. 
     In the EP tube, enzyme digestion was performed on the pLentis-CMV-IRES-Bsd vector, with an enzyme digestion system as follows: 2 μg of pLentis-CMV-IRES-Bsd vector plasmid, 3 μl of enzyme digestion buffer, 1 μl of BamHI and 1 μl of XhoI were added with water to a total volume of 30 μl, and let stand at 37° C. for 12 hours. The EP tube was taken out and added with 3.3 μl of 10× loading buffer; electrophoresis was performed by using 1% agarose gel; and after the electrophoresis, a PTRE-MCS-PGK-PURO vector fragment was recovered for later use. 
     The pLentis-CMV-IRES-Bsd was linked to the rtTA, with a system as follows: 2 μl of pLentis-CMV-IRES-Bsd, 2 μl of rtTA, 1 μl of ligase buffer, 0.5 μl of T4DNA ligase, and 4.5 μl of water were held at room temperature for linking for 4 hours. Then, the linking system was subjected to competent  Escherichia coli  transformation. On the second day, colonies were picked from the transformed plate, placed in an LB medium, and cultured overnight in a shaker at 37° C. Plasmids were extracted from cultured bacteria by using a plasmid extraction kit. Whether the rtTA fragments were successfully linked into the pLentis-CMV-IRES-Bsd vector was identified by enzyme digestion. Then, the correct vector was sent for sequencing to determine that the first expression vector pLentis-CMV-rtTA-IRES-Bsd was successfully constructed.
     1.2 Preparation of Virus of First Expression Vector pLentis-CMV-rtTA-IRES-Bsd   1) The cultured 293FT cells were digested, counted and then plated into a 10 cm culture dish at 3×10 6  cells/well, where the volume of culture solution was 10 ml.   2) In the evening of the second day, cellular states were observed, and transfection was performed if the cellular states were in a good condition. Chloroquine was added to the culture plate to a final concentration of 25 μM. A test tube was taken and added with sterile water and the following plasmids (5 μg of pMD2.G+15 μg of pSPAX2+20 μg of pLentis-CMV-rtTA-IRES-Bsd), until the total volume reached 1045 μl. Then 155 μl of 2MCaCl2 was added and mixed well. Finally, 1200 μl of 2×HBS was added by dripping over shaking. After the dripping was completed, a resulting mixture was quickly added to cell culture wells and gently shaken and mixed well.   3) In the morning of the third day, cellular states were observed, and the medium was changed to 10 ml of fresh DMEM medium.   4) In the morning of the fifth day, cellular states were observed. Supernatant in the culture dish was collected and filtered with a 0.45 μm filter, then placed in a high-speed centrifuge tube, and centrifuged at 50,000 g for 2 hours. The supernatant was carefully discarded, and the liquid was sucked to dryness with absorbent paper as much as possible. Then, 500 μl of HBSS was used for resuspension and precipitation. Precipitates were dissolved for 2 hours, then dispensed into small tubes, and stored at −70° C. to obtain the virus of the first expression vector pLentis-CMV-rtTA-IRES-Bsd.   

     1.3 Infection of B16 Tumor Cells Using the Virus of the First Expression Vector pLentis-CMV-rtTA-IRES-Bsd 
     The cultured mouse melanoma cells B16 were digested, inoculated into a 6-well plate at 10 5  cells/well, with a culture volume of 1 ml. After 24 hours, 10 μl of the virus of the first expression vector pLentis-CMV-rtTA-IRES-Bsd was added. After the resulting mixture was incubated in an incubator for 24 hours, supernatant was discarded and replaced with fresh medium to continue culturing. After the cells grew all over, the cells were transferred to a culture flask. Blasticidin was added at a concentration suitable for these cells to continue culturing. The medium was changed every two days, and the concentration of the blasticidin was kept at 8 μg/ml. After one week of screening, the survived cells were cells that stably expressed the regulator protein, and these cells were named as B16 (rtTA). 
     Example 2 Effect of Induced Expression of Green Fluorescent Protein (GFP) on Tumor Growth 
     2.1 Construction of Regulatable Expression Vector Encoding Green Fluorescent Protein (GFP) 
     A PCR reaction was conducted with a GFP gene as a template by using primers to amplify GFP genes, where PCR conditions were as listed in the instructions of the PrimeStarHS DNA polymerase. After agarose gel electrophoresis was performed for the PCR, the gel was extracted with a gel extraction kit. Then, enzyme digestion was performed by using BamHI and EcoRI, with an enzyme digestion system as follows: 30 μg of PCR product, 4 μl of digestion buffer, 1 μl of BamHI and 1 μl of EcoRI were added with water until the total volume reached 40 μl, and then let stand at 37° C. for 12 hours. An EP tube was taken out and added with 4.4 μl of 10× loading buffer; electrophoresis was performed by using 1% agarose gel; and after the electrophoresis, a GFP gene fragment was recovered for later use. 
     Enzyme digestion was performed on a regulatable expression vector, with a system as follows: 2 μg of pLentis-PTRE-MCS-PGK-PURO plasmid, 3 μl of enzyme digestion buffer, 1 μl of BamHI and 1 μl of EcoRI were added with water to a total volume of 30 μl, and let stand at 37° C. for 12 hours. An EP tube was taken out and added with 3.3 μl of 10× loading buffer; electrophoresis was performed by using 1% agarose gel; and after the electrophoresis, a fragment was recovered for later use. The pLentis-PTRE-MCS-PGK-PURO was linked to the GFP, with a linking system including: 2 μl of pLentis-PTRE-MCS-PGK-PURO, 2 μl of GFP, 1 μl of ligase buffer, 0.5 μl of T4DNA ligase, and 4.5 μl of water. The mixture was left at room temperature for linkage for 4 hours. Then, the linking system was subjected to competent  Escherichia coli  transformation. On the second day, colonies were picked from the transformed plate, placed in an LB medium, and cultured overnight in a shaker at 37° C. Plasmids were extracted from cultured bacteria by using a plasmid extraction kit. Whether the fragment was successfully linked into the vector was identified by enzyme digestion. Then, the correct vector was sent for sequencing to determine that the second expression vector pLentis-CMV-rtTA-IRES-Bsd was successfully constructed. 
     2.2 Preparation of Cells Regulating and Expressing GFP 
     A virus of a GFP-expressing vector was prepared with a method the same as that for preparing the virus of the first expression vector, to obtain a virus of a second expression vector pLentis-PTRE-GFP-PGK-PURO. 
     The cultured tumor cells B16 (rtTA) were digested, inoculated into a 6-well plate at 10 5  cells/well, with a culture volume of 1 ml. After 24 hours, 10 μl of the virus of the second regulatable expression vector pLentis-PTRE-GFP-PGK-PURO was added. After the resulting mixture was continuously incubated in an incubator for 24 hours, supernatant was discarded and replaced with fresh medium to continue culturing. After the cells grew all over, the cells were transferred to a culture flask. Puromycin was added at a final concentration of 3 μg/ml. After the culturing was continued for three days, the survived cells were cells capable of regulating and expressing GFP, which were named as B16 (rtTA)-GFP. 
     2.3 Effect of Regulated Expression of GFP on Tumor Growth 
     The cells B16(rtTA)-GFP in a logarithmic growth phase were digested, diluted with HBSS to 2×10 6  cells/ml, and injected into the right backs of a total of 10 C57BL/6 female mice being 8-10 weeks old at 50 μl/mouse by using a 1 ml syringe. After tumors grew, the mice were fed with water containing 2 g/L doxycycline, and the tumor growth in the mice was recorded, as shown in  FIG. 1 . The results showed that the induced expression of GFP had no inhibitory effect on tumor growth (in  FIG. 1 , each broken line represented the tumor area in one mouse). The survival curve of each group of mice was shown in  FIG. 2 . 
     Example 3 Design of Protein Heterodimer 
     The following protein heterodimers were designed: mIL12bscL19-IL2IL12aGMCSF, mIL12bscF8-IL2IL12aGMCSF, mIL12bscNHS76-IL2IL12aGMCSF, mIL12bscL19-scL19IL12aIL2GMCSF, mIL12bscF8-scF8IL12aIL2GMCSF, mIL12bscNHS76-scNHS76IL12aIL2GMCSF, hIL12bscF8-IL2IL12aGMCSF, hIL12bscF8-scF8IL12aIL2GMCSF, hIL12bscNHS76-scNHS76IL12aIL2GMCSF. The structures of the protein heterodimers above were shown in the figures ( FIG. 3  to  FIG. 11 ). 
     For example,  FIG. 3  shows the structure of a protein heterodimer mIL12bscL19-IL2IL12aGMCSF, where “m” in the formula represents that the cytokines are derived from mice. The protein heterodimer includes a first polypeptide chain and a second polypeptide chain different from the first polypeptide chain. In the second polypeptide chain, mIL12bscL19 represents the sequential inclusion of interleukin IL12b and the targeting moieties L19V H  and L19V L  from the N-terminal to the C-terminal, and the targeting moieties L19V H  and L19V L  located at the C-terminal of the second polypeptide chain may be represented by scL19. In the first polypeptide chain, IL2IL12aGMCSF represents the sequential inclusion of interleukin IL2, interleukin IL12a and granulocyte macrophage colony stimulating factor (GMCSF) from the N-terminal to the C-terminal. 
     For example,  FIG. 4  shows the structure of a protein heterodimer mIL12bscF8-IL2IL12aGMCSF, where “m” in the formula represents that the cytokines are derived from mice. The protein heterodimer includes a first polypeptide chain and a second polypeptide chain different from the first polypeptide chain. In the second polypeptide chain, mIL12bscF8 represents the sequential inclusion of interleukin IL12b and the targeting moieties F8V H  and F8V L  from the N-terminal to the C-terminal, and the targeting moieties F8V H  and F8V L  located at the C-terminal of the second polypeptide chain may be represented by scF8. In the first polypeptide chain, IL2IL12aGMCSF represents the sequential inclusion of interleukin IL2, interleukin IL12a and granulocyte macrophage colony stimulating factor (GMCSF) from the N-terminal to the C-terminal. 
     For example,  FIG. 5  shows the structure of a protein heterodimer mIL12bscNHS76-IL2IL12aGMCSF, where “m” in the formula represents that the cytokines are derived from mice. The protein heterodimer includes a first polypeptide chain and a second polypeptide chain different from the first polypeptide chain. In the second polypeptide chain, mIL12bscNHS76 represents the sequential inclusion of interleukin IL12b and the targeting moieties NHS76V H  and NHS76V L  from the N-terminal to the C-terminal, and the targeting moieties NHS76V H  and NHS76V L  located at the C-terminal of the second polypeptide chain may be represented by scNHS76. In the first polypeptide chain, IL2IL12aGMCSF represents the sequential inclusion of interleukin IL2, interleukin IL12a and granulocyte macrophage colony stimulating factor (GMCSF) from the N-terminal to the C-terminal. 
     For example,  FIG. 6  shows the structure of a protein heterodimer mIL12bscL19-scL19IL12aIL2GMCSF, where “m” in the formula represents that the cytokines are derived from mice. The protein heterodimer includes a first polypeptide chain and a second polypeptide chain different from the first polypeptide chain. In the second polypeptide chain, mIL12bscL19 represents the sequential inclusion of interleukin IL12b and the targeting moieties L19V H  and L19V L  from the N-terminal to the C-terminal, and the targeting moieties L19V H  and L19V L  located at the C-terminal of the second polypeptide chain may be represented by bscL19. In the first polypeptide chain, scL19IL12aIL2GMCSF represents the sequential inclusion of the targeting moieties L19V H  and L19V L , interleukin IL12a, interleukin IL2 and the granulocyte macrophage colony stimulating factor (GMCSF) from the N-terminal to the C-terminal, where the targeting moieties L19V H  and L19V L  located at the N-terminal of the first polypeptide chain may be represented by scL19. For example,  FIG. 9  shows the structure of a protein heterodimer hIL12bscF8-IL2IL12aGMCSF, where “h” in the formula represents that the cytokines are derived from humans. The protein heterodimer includes a first polypeptide chain and a second polypeptide chain different from the first polypeptide chain. In the second polypeptide chain, hIL12bscF8 represents the sequential inclusion of interleukin IL12b and the targeting moieties F8V H  and F8V L  from the N-terminal to the C-terminal, and the targeting moieties F8V H  and F8V L  located at the C-terminal of the second polypeptide chain may be represented by scF8. In the first polypeptide chain, IL2IL12aGMCSF represents the sequential inclusion of interleukin IL2, interleukin IL12a and granulocyte macrophage colony stimulating factor (GMCSF) from the N-terminal to the C-terminal. 
     For example,  FIG. 10  shows the structure of a protein heterodimer hIL12bscF8-scF8IL12aIL2GMCSF, where “h” in the formula represents that the cytokines are derived from humans. The protein heterodimer includes a first polypeptide chain and a second polypeptide chain different from the first polypeptide chain. In the second polypeptide chain, hIL12bscF8 represents the sequential inclusion of interleukin IL12b and the targeting moieties F8V H  and F8V L  from the N-terminal to the C-terminal, and the targeting moieties F8V H  and F8V L  located at the C-terminal of the second polypeptide chain may be represented by scF8. In the first polypeptide chain, scF8IL12aIL2GMCSF represents the sequential inclusion of the targeting moieties F8V H  and F8V L , interleukin IL12a, interleukin IL2 and the granulocyte macrophage colony stimulating factor (GMCSF) from the N-terminal to the C-terminal, where the targeting moieties F8V H  and F8V L , located at the N-terminal of the first polypeptide chain may be represented by scF8. 
     Example 4 Effect of Induced Expression of mIL12bscF8-IL2IL12aGMCSF on Tumor Growth 
     4.1 Construction of Regulatable Expression Vector mIL12bscF8-IL2IL12aGMCSF 
     A gene coding sequence of mIL12bscF8-IL2IL12aGMCSF with BamHI, BglII and XhoI, EcoRI restriction enzyme sites on both ends were synthesized. Then, enzyme digestion was performed by using BamHI or BglII and XhoI or EcoRl, with an enzyme digestion system as follows: 5 μg of mIL12bscF8-IL2IL12aGMCSF plasmid, 4 μl of enzyme digestion buffer, 1 μl of BamHI and 1 μl of XhoI were added with water to a total volume of 40 μl, and let stand at 37° C. for 12 hours. An EP tube was taken out and added with 4.4 μl of 10× loading buffer; electrophoresis was performed by using 1% agarose gel; and after the electrophoresis, an mIL12bscF8-IL2IL12aGMCSF gene fragment was recovered for later use. 
     The protein heterodimer mIL12bscF8-IL2IL12aGMCSF includes the amino acid sequences as set forth in SEQ ID NO. 13 and SEQ ID NO. 17, and a nucleotide sequence encoding the mIL12bscF8-IL2IL12aGMCSF is as set forth in SEQ ID NO. 25. 
     Enzyme digestion was performed on a regulatable expression vector pLentis-PTRE-MCS-PGK-PURO, with an enzyme digestion system as follows: 2 μg of pLentis-PTRE-MCS-PGK-PURO vector plasmid, 3 μl of enzyme digestion buffer, 1 μl of BamHI and 1 μl of XhoI were added with water to a total volume of 30 μl, and let stand at 37° C. for 12 hours. The EP tube was taken out and added with 3.3 μl of 10× loading buffer; electrophoresis was performed by using 1% agarose gel; and after the electrophoresis, a pLentis-PTRE-MCS-PGK-PURO vector fragment was recovered for later use. 
     The pLentis-PTRE-MCS-PGK-PURO was linked to the mIL12bscF8-IL2IL12aGMCSF, with a linking system including: 2 μl of pLentis-PTRE-MCS-PGK-PURO, 2 μl of mIL12bscF8-IL2IL12aGMCSF, 1 μl of ligase buffer, 0.5 μl of T4DNA ligase, and 4.5 μl of water. The mixture was left at room temperature for linkage for 4 hours. Then, the linking system was subjected to competent  Escherichia coli  transformation. On the second day, colonies were picked from the transformed plate, placed in an LB medium, and cultured overnight in a shaker at 37° C. Plasmids were extracted from cultured bacteria by using a plasmid extraction kit. Whether the fragment was successfully linked into the vector was identified by enzyme digestion. Then, the correct vector was sent for sequencing to determine that the second expression vector pLentis-PTRE-mIL12bscF8-IL2IL12aGMCSF-PGK-PURO was successfully constructed. 
     4.2 Preparation of Cells Capable of Regulating and Expressing mIL12bscF8-IL2IL12aGMCSF 
     A virus of an mIL12bscF8-IL2IL12aGMCSF-expressing vector was prepared with a method the same as that for preparing the virus of the first expression vector, to obtain a virus of a second expression vector pLentis-PTRE-mIL12bscF8-IL2IL12aGMCSF-PGK-PURO. 
     The cultured tumor cells B16 (rtTA) were digested, inoculated into a 6-well plate at 10 5  cells/well, with a culture volume of 1 ml. After 24 hours, 10 μl of the virus of the second regulatable expression vector pLentis-PTRE-mIL12bscF8-IL2IL12aGMCSF-PGK-PURO was added. After the resulting mixture was continuously incubated in an incubator for 24 hours, supernatant was discarded and replaced with fresh medium to continue culturing. After the cells grew all over, the cells were transferred to a culture flask. Puromycin was added at a final concentration of 3 μg/ml. After the culturing was continued for three days, the survived cells were cells capable of regulating and expressing mIL12bscF8-IL2IL12aGMCSF, which were named as B16(rtTA)-mIL12bscF8-IL2IL12aGMCSF. 
     4.3 In Vitro Assay of the Effect of Induced Expression of mIL12bscF8-IL2IL12aGMCSF 
     B16 (rtTA) mIL12bscF8-IL2IL12aGMCSF cells were plated into a 24-well plate at 5×10 4  per well. After 24 hours, 100 ng/ml doxycycline (DOX) was added to the wells. The culture was continued for 72 hours, and the supernatant was collected. The expression quantity of the protein heterodimer in the supernatant was detected by using a mouse IL12p70 ELISA kit, where the operations were conducted according to the instructions of the kit. Wells without DOX induction were used as controls. As shown in  FIG. 12 , the added DOX induced the expression of the protein heterodimer mIL12bscF8-IL2IL12aGMCSF. 
     4.4 Effect of Induced Expression of mIL12bscF8-IL2IL12aGMCSF on Tumor Growth. 
     The cells B16(rtTA)-mIL12bscF8-IL2IL12aGMCSF in a logarithmic growth phase were digested, diluted with HBSS to 2×10 6  cells/ml, and injected into the right backs of a total of 10 C57BL/6 female mice being 8-10 weeks old at 50 μl/mouse by using a 1 ml syringe. After tumors grew, the mice were fed with water containing 2 g/L doxycycline, and the tumor growth and tumor clearance rate in the mice were recorded, with the number of tumor-cleared mice/the total number of mice=7/10, as shown in  FIG. 13 . mIL12bscF8-IL2IL12aGMCSF can induce tumor regression in some mice. 
     Example 5 Effect of Induced Expression of mIL12bscF8-scF8IL12aIL2GMCSF on Tumor Growth 
     5.1 Construction of Regulatable Expression Vector mIL12bscF8-scF8IL12aIL2GMCSF 
     A gene coding sequence of mIL12bscF8-scF8IL12aIL2GMCSF with BamHI, BglII and XhoI, EcoRI restriction enzyme sites on both ends were synthesized. Then, enzyme digestion was performed by using BamHI or BglII and XhoI or EcoRl, with an enzyme digestion system as follows: 5 μg of mIL12bscF8-scF8IL12aIL2GMCSF plasmid, 4 μl of enzyme digestion buffer, 1 μl of BamHI and 1 μl of XhoI were added with water to a total volume of 4 μl, and let stand at 37° C. for 12 hours. An EP tube was taken out and added with 4.4 μl of 10× loading buffer; electrophoresis was performed by using 1% agarose gel; and after the electrophoresis, a mIL12bscF8-scF8IL12aIL2GMCSF gene fragment was recovered for later use. 
     The protein heterodimer mIL12bscF8-scF8IL12aIL2GMCSF includes the amino acid sequences as set forth in SEQ ID NO. 13 and SEQ ID NO. 19, and a nucleotide sequence encoding the mIL12bscF8-scF8IL12aIL2GMCSF is as set forth in SEQ ID NO. 28. 
     Enzyme digestion was performed on a regulatable expression vector pLentis-PTRE-MCS-PGK-PURO, with an enzyme digestion system as follows: 2 μg of pLentis-PTRE-MCS-PGK-PURO vector plasmid, 3 μl of enzyme digestion buffer, 1 μl of BamHI and 1 μl of XhoI were added with water to a total volume of 30 μl, and let stand at 37° C. for 12 hours. The EP tube was taken out and added with 3.3 μl of 10× loading buffer; electrophoresis was performed by using 1% agarose gel; and after the electrophoresis, a pLentis-PTRE-MCS-PGK-PURO vector fragment was recovered for later use. 
     The pLentis-PTRE-MCS-PGK-PURO was linked to the mIL12bscF8-scF8IL12aIL2GMCSF, with a linking system including: 2 μl of pLentis-PTRE-MCS-PGK-PURO, 2 μl of mIL12bscF8-scF8IL12aIL2GMCSF, 1 μl of ligase buffer, 0.5 μl of T4DNA ligase, and 4.5 μl of water. The mixture was left at room temperature for linkage for 4 hours. Then, the linking system was subjected to competent  Escherichia coli  transformation. On the second day, colonies were picked from the transformed plate, placed in an LB medium, and cultured overnight in a shaker at 37° C. Plasmids were extracted from cultured bacteria by using a plasmid extraction kit. Whether the fragment was successfully linked into the vector was identified by enzyme digestion. Then, the correct vector was sent for sequencing to determine that the second expression vector pLentis-PTRE-mIL12bscF8-scF8IL12aIL2GMCSF-PGK-PURO was successfully constructed. 
     5.2 Preparation of Cells Capable of Regulating and Expressing mIL12bscF8-scF8IL12aIL2GMCSF 
     A virus of an mIL12bscF8-scF8IL12aIL2GMCSF-expressing vector was prepared with a method the same as that for preparing the virus of the first expression vector, to obtain a virus of a second expression vector pLentis-PTRE-mIL12bscF8-IL2IL12aGMCSF-PGK-PURO. 
     The cultured tumor cells B16 (rtTA) were digested, inoculated into a 6-well plate at 10 5  cells/well, with a culture volume of 1 ml. After 24 hours, 10 μl of the virus of the second regulatable expression vector pLentis-PTRE-mIL12bscF8-scF8IL12aIL2GMCSF-PGK-PURO was added. After the resulting mixture was continuously incubated in an incubator for 24 hours, supernatant was discarded and replaced with fresh medium to continue culturing. After the cells grew all over, the cells were transferred to a culture flask. Puromycin was added at a final concentration of 3 μg/ml. After the culturing was continued for three days, the survived cells were cells capable of regulating and expressing mIL12bscF8-scF8IL12aIL2GMCSF, which were named as B16(rtTA)-mIL12bscF8-scF8IL12aIL2GMCSF. 
     5.3 Effect of Induced Expression of mIL12bscF8-scF8IL12aIL2GMCSF on Tumor Growth. 
     The cells B16(rtTA)-mIL12bscF8-scF8IL12aIL2GMCSF in a logarithmic growth phase were digested, diluted with HBSS to 2×10 6  cells/ml, and injected into the right backs of a total of 10 C57BL/6 female mice being 8-10 weeks old at 50 μl/mouse by using a 1 ml syringe. After tumors grew, the mice were fed with water containing 2 g/L doxycycline, and the tumor growth and tumor clearance rate in the mice were recorded, with the number of tumor-cleared mice/the total number of mice=8/10, as shown in  FIG. 14 . mIL12bscF8-scF8IL12aIL2GMCSF can induce tumor regression in some mice. 
     Example 6 Construction of Cells Expressing hIL12bscF8-IL2IL12aGMCSF, hIL12bscF8-scF8IL12aIL2GMCSF, and hIL12bscNHS76-scNHS76IL12aIL2GMCSF 
     6.1 Construction of Vector Capable of Regulating and Expressing Target Gene 
     In the EP tube, enzyme digestion was performed on the pLentis-CMV-MCS-TRES-PURO vector, with a system as follows: 2 μg of pLentis-CMV-MCS-IRES-PURO vector plasmid, 3 μl of enzyme digestion buffer, 1 μl of BamHI and 1 μl of XhoI were added with water to a total volume of 30 μl, and let stand at 37° C. for 12 hours. The EP tube was taken out and added with 3.3 μl of 10× loading buffer; electrophoresis was performed by using 1% agarose gel; and after the electrophoresis, a pLentis-CMV-MCS-IRES-PURO vector fragment was recovered for later use. 
     The DNA sequences of hIL12bscF8-IL2IL12aGMCSF, hIL12bscF8-scF8IL12aIL2GMCSF, and hIL12bscNHS76-scNHS76IL12aIL2GMCSF were synthesized respectively, where during the synthesis, the restriction enzyme site BamHI or BglII was added to a 5′-terminal, and the restriction enzyme site XhoI or EcoRI was added to a 3′-terminal. The synthesized plasmid with the target gene was enzyme-digested, with a system as follows: 5 kg of plasmid, 4 μl of enzyme-digestion buffer, 1 μl of BamHI, and 1 μl of XhoI were added with water to a total volume of 40 μl, and let stand at 37° C. for 12 hours. An EP tube was taken out and added with 4.4 μl of 10× loading buffer; electrophoresis was performed by using 1% agarose gel; and after the electrophoresis, a mIL2IL12aIL12bGMCSF gene fragment was recovered for later use. 
     The protein heterodimer hIL12bscF8-IL2IL12aGMCSF includes the amino acid sequences as set forth in SEQ ID NO. 15 and SEQ ID NO. 21, and a nucleotide sequence encoding the hIL12bscF8-IL2IL12aGMCSF is as set forth in SEQ ID NO. 30. 
     The protein heterodimer hIL12bscF8-scF8IL12aIL2GMCSF includes the amino acid sequences as set forth in SEQ ID NO. 15 and SEQ ID NO. 22, and a nucleotide sequence encoding the hIL12bscF8-scF8IL12aIL2GMCSF is as set forth in SEQ ID NO. 31. 
     The protein heterodimer hIL12bscNHS76-scNHS76IL12aIL2GMCSF includes the amino acid sequences as set forth in SEQ ID NO. 16 and SEQ ID NO. 23, and a nucleotide sequence encoding the hIL12bscNHS76-scNHS76IL12aIL2GMCSF is as set forth in SEQ ID NO. 32. 
     The pLentis-CMV-MCS-TRES-PURO was linked to the hIL12bscF8-IL2IL12aGMCSF, the hIL12bscF8-scF8IL12aIL2GMCSF, and the hIL12bscNHS76-scNHS76IL12aIL2GMCSF respectively, with a linking system including: 2 μl of pLentis-CMV-MCS-IRES-PURO, 2 μl of gene fragment, 1 μl of ligase buffer, 0.5 μl of T4DNA ligase, and 4.5 μl of water. The mixture was left at room temperature for linkage for 4 hours. Then, the linking system was subjected to competent  Escherichia coli  transformation. On the second day, colonies were picked from the transformed plate, placed in an LB medium, and cultured overnight in a shaker at 37° C. Plasmids were extracted from cultured bacteria by using a plasmid extraction kit. Whether the fragments were successfully linked into the vector was identified by enzyme digestion. Then, the correct vectors were sent for sequencing to determine that the construction was successful, thereby obtaining the vector pLentis-CMV-hIL12bscF8-IL2IL12aGMCSF-IRES-PURO, the vector pLentis-CMV-hIL12bscF8-scF8IL12aIL2GMCSF-IRES-PURO, and the vector pLentis-CMV-hIL12bscNHS76-scNHS76IL12aIL2GMCSF-IRES-PURO, which expressed the target gene. 
     6.2 Preparation of Virus of Expression Vector
     1) The cultured 293FT cells were digested, counted and then plated into a 10 cm culture dish at 3×10 6  cells/well, where the volume of culture solution was 10 ml, and a total of five plates were spread.   2) In the evening of the second day, cellular states were observed, and transfection was performed if the cellular states were good. Chloroquine was added to the culture plates to a final concentration of 25 μM. A test tube was taken and added with sterile water and the following plasmids (6 μg of pMD2.G+15 μg of pSPAX2+20 kg of expression vector), until the total volume reached 1045 μl. Then 155 μl of 2M CaCl 2 ) was added and mixed well. Finally, 1200 μl of 2×HBS was added by dripping over shaking. After the dripping was completed, a resulting mixture was quickly added to cell culture wells and gently shaken and mixed well.   3) In the morning of the third day, cellular states were observed, and the medium was changed to 10 ml of fresh DMEM medium.   4) In the morning of the fifth day, cellular states were observed. Supernatant in the culture dish was collected and filtered with a 0.45 km filter, then placed in a high-speed centrifuge tube, and centrifuged at 50,000 g for 2 hours. The supernatant was carefully discarded, and the liquid was sucked to dryness with absorbent paper as much as possible. Then, 200 μl of HBSS was used for resuspension and precipitation. Precipitates were dissolved for 2 hours, then dispensed into small tubes, and stored at −70° C.   

     6.3 Transfection of 293A Cells with Expression Virus 
     The cultured 293A cells were digested, inoculated into a 6-well plate at 10 5  cells/well, with a culture volume of 1 ml. After 24 hours, 10 μl of the virus expressing the above target gene was added. After the resulting mixture was continuously incubated in an incubator for 24 hours, supernatant was discarded and replaced with fresh medium to continue culturing. After the cells grew all over, the cells were transferred to a culture flask. Puromycin was added at a final concentration of 3 μg/ml. The culturing was continued by changing the medium every two days, where the concentration of the puromycin was maintained. After one week of screening, the survived cells were cells stably expressing the cytokines, and these cells were named as 293A(hIL12bscF8-IL2IL12aGMCSF), 293A(hIL12bscF8-scF8IL12aIL2GMCSF), and 293A(hIL12bscNHS76-scNHS76IL12aIL2GMCSF), respectively. 
     The constructed expression cells were plated into a 24-well plate at 5×10 4  per well, and cultured for 96 hours. The supernatant was collected. The expression of the protein heterodimer in the supernatant was detected by using a human IL12p70 ELISA kit, where the operations were conducted according to the instructions of the kit. As shown in  FIG. 15 , these cells are capable of producing a large amount of IL12p70, and the cells expressing the protein heterodimers were successfully constructed. 
     The foregoing detailed description is provided by way of explanation and examples, and is not intended to limit the scope of the appended claims. Various changes of the embodiments listed in the present application until now are obvious to those of ordinary skill in the art, and should be kept within the scope of the appended claims and equivalents thereof.