# Patent

## Title
Antibodies against glucagon receptor and their use

## Abstract

Disclosed are immunological compositions and methods for reducing activity of glucagon signaling using antibodies against glucagon receptor.

## Background
TECHNICAL FIELD
The present invention relates to the compositions and methods related to antibodies against glucagon receptor and derivatives of these antibodies. The invention further concerns pharmaceutical compositions and derivatives useful in such methods. More specifically, the invention relates to the production, diagnostic use, and therapeutic use of monoclonal and polyclonal antibodies, and fragments thereof, which specifically bind to glucagon receptor.
BACKGROUND ART
Fasting hyperglycemia in patients with poorly controlled type II diabetes mellitus is closely associated with increased rates of glucose production which in turn can be ascribed to increased rates of gluconeogenesis. A number of studies have demonstrated that elevated glucagon level is partially responsible for the increased hepatic glucose production in patients with type 2 diabetes.
Glucagon is a 29-amino-acid hormone in the pancreatic alpha cells, which plays a major counter-regulatory role for insulin action. During fasting, glucagon secretion increases in response to the low circulating glucose levels. Increased glucagon secretion stimulates glucose production by promoting hepatic gluconeogenesis and glycogenolysis. In addition, glucagon reduces glycogen synthesis in the liver. Clinically, glucagon is administered to patients who are at risk for significant hypoglycemia. Conversely, inhibition of the glucagon pathway may offer a strategy for the treatment of type II diabetes.
The biological effects of glucagon are mediated through its binding to a specific receptor on cell surface, glucagon receptor, and subsequent activation of the signaling pathway. The glucagon receptor belongs to the family B G-protein coupled receptor (GPCR). It is predominantly expressed in liver and kidney, which reflects its primary role as a regulator of glucose output and gluconeogenesis in these tissues. The activation of glucagon receptor in the liver stimulates adenylyl cyclase activity and phosphoinositol turnover, resulting in increased expression of several key gluconeogenic enzymes.
Considering the key role of glucagon in control of hyperglycemia, strategy for inhibiting glucagon activation pathway can provide a therapeutic means to treat type II diabetes.
DISCLOSURE OF INVENTION
Technical Problem
The object of present invention is to provide antibodies against glucagon receptor.
Another object of the present invention is to provide recombinant vectors, host cells, isolated cell lines, and hybridomas for the production of such antibodies.
It is still another object of the present invention to provide pharmaceutical compositions containing the antibodies.
It is still another object of the present invention to provide methods for treating type II diabetes and related disease using these antibodies.
Solution to Problem
One aspect of the present invention relates to isolated antibodies, or antigen-binding portions or derivatives thereof, that specifically bind to glucagon receptor.
In one embodiment, the present invention provides an isolated antibody, or an antigen-binding portion or a derivative thereof, comprising:
(a) a first CDR set, CDR1, CDR2 and CDR3, that sequentially together comprise the amino acid sequences of heavy chain CDRs, CDR1, CDR2 and CDR3, sequentially together, that are included in the amino acid sequence as set forth in any one of SEQ ID Nos. 2, 4, 6, 8, 10, 12, 14, and 16;
(b) a second CDR set, CDR1, CDR2 and CDR3, that sequentially together comprises the amino acid sequences of light chain CDRs, CDR1, CDR2 and CDR3, sequentially together, that are included in the amino acid sequence set forth in any one of SEQ ID Nos. 18, 20, 22, 24, 26, 28 and 30; or,
(c) a combination of the first CDR set of (a) and the second CDR set of (b).
In a preferable embodiment, the antibody comprises a heavy chain or a light chain, or both of them, wherein said heavy chain comprises a heavy chain variable region selected from the group consisting of HC1 (SEQ ID No. 2); HC2 (SEQ ID No. 4); HC3 (SEQ ID No. 6); HC4 (SEQ ID No. 8); HC5 (SEQ ID No. 10); HC6 (SEQ ID No. 12); HC7 (SEQ ID No. 14); HC8 (SEQ ID No. 16); and antigen-binding fragments thereof; and said light chain comprises a light chain variable region selected from the group consisting of: LC1 (SEQ ID No. 18); LC2 (SEQ ID No. 20); LC3 (SEQ ID No. 22); LC4 (SEQ ID No. 24); LC5 (SEQ ID No. 26); LC6 (SEQ ID No. 28); LC7 (SEQ ID No. 30); and antigen-binding fragments thereof.
In a more preferable embodiment, the antibody of the present invention is selected from the group consisting of:
(a) an antibody comprising the amino acid sequences as set forth in SEQ ID No. 2 and SEQ ID No. 18 (Ab1);
(b) an antibody comprising the amino acid sequences as set forth in SEQ ID No. 4 and SEQ ID No. 20 (Ab2);
(c) an antibody comprising the amino acid sequences as set forth in SEQ ID No. 6 and SEQ ID No. 22 (Ab3);
(d) an antibody comprising the amino acid sequences as set forth in SEQ ID No. 8 and SEQ ID No. 24 (Ab4);
(e) an antibody comprising the amino acid sequences as set forth in SEQ ID No. 6 and SEQ ID No. 26 (Ab5);
(f) an antibody comprising the amino acid sequences as set forth in SEQ ID No. 10 and SEQ ID No. 26 (Ab6);
(g) an antibody comprising the amino acid sequences as set forth in SEQ ID No. 12 and SEQ ID No. 28 (Ab7);
(h) an antibody comprising the amino acid sequences as set forth in SEQ ID No. 14 and SEQ ID No. 30 (Ab8);
(i) an antibody comprising the amino acid sequences as set forth in SEQ ID No. 16 and SEQ ID No. 26 (Ab9); and,
(j) an antibody comprising the amino acid sequences as set forth in SEQ ID No. 10 and SEQ ID No. 22 (Ab10).
In another aspect, the present invention relates to an isolated antibody, or an antigen-binding portion or a derivative thereof, which competes for binding to glucagon receptor.
In one embodiment, the isolated antigen binding agent binds to the human glucagon receptor with substantially the same Kd as a reference antibody, or inhibits glucagon stimulation of the receptor with substantially the same IC50 of the reference antibody, or competes for binding with the reference antibody.
In another aspect, the present invention relates to an isolated antibody, or an antigen-binding portion or a derivative thereof, comprising:
(a) a first CDR set, CDR1, CDR2 and CDR3, that sequentially together are at least 85% identical in amino acid sequence to heavy chain CDRs, CDR1, CDR2 and CDR3, sequentially together, that are included in the amino acid sequence as set forth in any one of SEQ ID Nos. 2, 4, 6, 8, 10, 12, 14, and 16;
(b) a second CDR set, CDR1, CDR2 and CDR3, that sequentially together are at least 85% identical in amino acid sequence to light chain CDRs, CDR1, CDR2 and CDR3, sequentially together, that are included in the amino acid sequence set forth in any one of SEQ ID Nos. 18, 20, 22, 24, 26, 28 and 30; or,
(c) a combination of the first CDR set of (a) and the second CDR set of (b),
wherein said antibody, antigen-binding portion or derivative competes for glucagon binding to glucagon receptor.
The antibody may comprise a heavy chain comprising a variable region comprising an amino acid sequence at least 85%, preferably 90%, more preferably 95%, and most preferably 99% identical to the amino acid sequence selected from SEQ ID No. 2, 4, 6, 8, 10, 12, 14 or 16. Further, the antibody may comprise a light chain comprising a variable region comprising an amino acid sequence at least 85%, preferably 90%, more preferably 95%, and most preferably 99% identical to the amino acid sequence selected from SEQ ID No. 18, 20, 22, 24, 26, 28 or 30.
In another aspect, the present invention provides an isolated antibody or an antigen binding portion, comprising an amino acid sequence selected from the group consisting of:
(a) a heavy chain CDR3 sequence that differs by no more than a total of three amino acid additions, deletions, and/or nonconservative substitutions from a CDR3 sequence selected from SEQ ID Nos. 2, 4, 6, 8, 10, 12, 14 and 16;
(b) a light chain CDR3 sequence that differs by no more than a total of three amino acid additions, deletions, and/or nonconservative substitutions from a CDR3 sequence selected from SEQ ID Nos. 18, 20, 22, 24, 26, 28 and 30; or,
(c) a combination of a heavy chain CDR3 sequence of (a) and the light chain CDR3 sequence of (b),
wherein said antibody or antigen binding portion binds to glucagon receptor.
Another aspect of the present invention relates to a pharmaceutical composition including an antibody or functional fragment thereof, and a pharmaceutically acceptable carrier. Compositions of the invention comprise the heavy and/or light chain, the variable domains thereof, or antigen-binding portions thereof, or nucleic acid molecules encoding the antibody, antibody chain, or variable domain thereof, and a mixture with one or more pharmaceutically acceptable carrier or fusion partner. Compositions of the invention may further comprise another component, such as a therapeutic agent or a diagnostic agent.
Yet another aspect of the present invention relates to an isolated nucleic acid comprising a polynucleotide sequence encoding the light chain variable domain, the heavy chain variable domain, or both, of the antibody. The nucleic acid may comprise the nucleotide sequence as set forth in one or more of SEQ ID Nos. 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27 and 29.
A further aspect of the present invention relates to a recombinant expression vector, comprising the nucleic acid of reference sequences.
Still a further aspect of the present invention relates to a host cell transformed with the vector.
Still a further aspect of the present invention relates to an isolated cell line, which produces the antibody, or the heavy chain or light chain or an antigen-binding portion thereof.
Still a further aspect of the present invention relates to a hybridoma producing the antibody, or the heavy chain or light chain or an antigen-binding portion thereof.
Still a further aspect of the present invention relates to a method for lowering blood glucose, improving glucose tolerance, or for treating, preventing or inhibiting type II diabetes, dyslipodemia, or a related disease in a subject in need thereof, comprising the step of administering to the subject the antibody, the antigen-binding portion or the derivative thereof, or the pharmaceutical composition. The glucagon receptor antibodies can be administered alone, or in combination with additional antibodies or other medicines.
Advantageous Effects of Invention
This invention provides compositions and methods based on interfering with glucagon receptor activation, including, but not limited to, by binding to the extracellular portion of glucagon receptor. Antagonists of the invention, as described herein, provide important therapeutic and diagnostic agents for use in targeting pathological conditions associated with diabetes mellitus and related disease. Accordingly, the invention provides methods, compositions, kits, and articles of manufacture related to modulating glucagon receptor pathway.



BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a graphical representation showing the ability of selected antibodies binding to the glucagon receptor that is expressed on cell surface. Varying amounts of antibodies were added to the CHO cells expressing the full length human glucagon receptor. After washing, antibodies remained to the cells were detected by HRP conjugated anti-human antibody followed by substrate addition for HRP activity.
FIG. 2 shows a graph illustrating inhibition of cAMP production by antibodies against glucagon receptor upon glucagon stimulation. A stable cell line expressing full length human glucagon receptor was incubated with varying amounts of antibodies. After 15 min, 100 pM of glucagon was added to the cells and level of cAMP was measured using cAMP HTRF kit (CIS Bio). The average values and standard deviation from duplicate samples are shown.
FIGS. 3 to 5 show the predicted amino acid sequences of light and heavy chain variable domains of isolated anti-glucagon receptor antibodies. The underlined sequences represent, from left to right, the CDR1, CDR2, and CDR3.
FIG. 6 shows the blood glucose level in high fat induced obese mice injected with the selected antibody (Ab7) at 1 mg/kg and 7 mg/kg. Blood glucose was measured at day 0, 1, 2, 3, and 10 after single injection of either antibody or buffer control. The values are calculated average and standard deviation from nine to ten mice in each group.
FIG. 7 represents the graphical view of fasting plasma glucose levels and basal rates of hepatic glucose production (HGP) in high fat induced obese mice. Basal HGP was determined by radioisotope dilution method (Choi C. S. et al, Proc Natl Acad Sci U-S-A, 2007, 104:16480-85). Fasting plasma glucose levels and basal HGP rates were significantly decreased in mice injected with 7 mg/kg of Ab7, compared with vehicle injected group, while basal glucose clearance rates was not different between two groups. Data are expressed as mean values+/−SEM for 10 mice per group.



Mode for the Invention
Definitions
The term, ‘an antibody,’ as used herein, means a protein consisting of one or more polypeptides substantially encoded by all or part of the recognized immunoglobulin genes. The recognized immunoglobulin genes, for example in humans, include the kappa, lambda, and heavy chain genetic loci, which together comprise the myriad variable region genes, and the constant region genes. Herein, ‘antibody’ may mean ‘a specific antigen binding agent.’ A skilled person in the art would readily appreciate that the antibody can be used as a therapeutic or diagnostic agent, and thus, ‘antibody’ may also be referred to as ‘a therapeutic agent’ or ‘a diagnostic agent.’
An ‘isolated antibody,’ as used herein, is intended to refer to an antibody that is substantially free of other antibodies having different antigenic specificities (e.g., an isolated antibody that specifically binds glucagon receptor is substantially free of antibodies that specifically bind antigens other than glucagon receptor). An isolated antibody that specifically binds glucagon receptor may, however, have cross-reactivity to other antigens, such as glucagon receptor from other species. Moreover, an isolated antibody may be substantially free of other cellular material and/or chemicals. Further, an isolated antibody, e.g., an isolated human antibody, can be a chimeric antibody wherein, e.g., variable regions, CDR domains, or isotypes derived from a different human source are grafted to the parent human antibody.
The term, ‘neutralizing antibody,’ for glucagon receptor refers to an antibody that can inhibit a glucagon dependent stimulation of its receptor by about 10 ̃120%, preferably by at least 30, 50, 70, 80, 90, 100% or more, depending on the assay. The capacity of glucagon receptor antibodies to inhibit glucagon signaling is preferably assessed by at least one suitable cell based assay, as described herein and/or as known in the art. One example is to measure the production of cAMP upon stimulation with glucagon, using a kit such as cAMP HTRF kit (CisBio).
The term, ‘conservative amino acid substitutions,’ as used herein, are substitutions that replace an amino acid residue with one imparting similar or better (for the intended purpose) functional and/or chemical characteristics, as one of ordinary skill in the art will appreciate. Conservative amino acid substitutions are often ones in which the amino acid residue is replaced with an amino acid residue with a similar side chain. Families of amino acid residues having similar side chains have been defined in the art. For examples, lysine, arginine, histidine for basic side chains, aspartic acid and glutamic acid for acidic side chains, glycine, asparagines, glutamine, serine, threonine, tyrosine, cysteine, tryptophan for uncharged polar side chains, alanine, valine, leucine, threonine, isoleucine, proline, phenylalanine, methionine for non-polar side chains, and tyrosine, phenylalanine, tryptophan, histidine for aromatic side chains. The substitution is of amino acids with generally similar physiochemical properties such that the substitutions do not substantially alter peptide, polypeptide or protein characteristics, or activity.
Percent identity between two amino acid sequences is a function of the number of amino acid positions shared by the sequences (i.e. a number of the positions with the same amino acid divided by total number of positions multiplied by 100), taking into account the number of gaps, and length of each gap, which need to be introduced for optimal alignment of the two sequences. Antibodies of the present invention also include those in which modification have been made to the framework residues within VH and/or VL to improve one or more properties of the antibody. Typically, such framework modifications are made to decrease the immunogenecity or improve the stability of the antibody.
In addition to modifications made within the framework or CDR regions, antibodies of the invention may be engineered to include modifications within the Fc region, typically to alter one or more functional properties of the antibody, such as serum half life, complement fixation, Fc receptor binding, and/or antigen dependent cellular cytotoxicity. Antibody fragments or derived agents are a part of antibodies or antibodies in a different format comprising a portion that binds to an antigen, and optionally, a scaffold or framework portion that allows the antigen-binding portion of the antigen-binding protein to the antigen. For example, changes in framework or CDR, such as amino acid substitutions, deletions, or additions, can be made yet to maintain its antigen-binding ability. Alternatively, antigen-binding portion of the invention can be derivatized or linked to another molecule (e.g., another peptide, protein, polymers, or chemicals).
Antigen-binding portion of antibodies can be modified to a single chain antibody, a diabody, a triabody, a tetrabody, a Fab fragment (monovalent fragment with VL, CL, VH, and CH1), a F(ab′)2 fragment (two Fab fragments linked by a disulfide bridge), Fd (VH and CH1 domains), scFv (VL and VH is joined by a linker), a domain antibody, bispecific antibodies, a minibody, a scab (an antibody fragment containing VH and VL as well as either CL or CH1), an IgD antibody, an IgE antibody, an IgM antibody, an IgG1 antibody, an IgG2 antibody, an Ig3 antibody, an IgG4 antibody, or any derivatives of antibody constant domain, and artificial antibodies based upon protein scaffolds, including, but not limited to, fibronectin type, avimers, or cytochrome B.
Detailed Description of the Invention
The present invention provides isolated recombinant and/or synthetic antibodies against glucagon receptor, as well as compositions and nucleic acid molecules comprising at least one polynucleotide encoding at least one anti-glucagon receptor antibody. This invention provides compositions and methods based on, but not limited to, interfering with glucagon receptor signaling by binding to the extracellular portion of glucagon receptor. Antagonists of the invention, as described herein, provide important therapeutic and diagnostic agents for use in targeting pathological conditions associated with diabetes mellitus and related disease. Accordingly, the invention provides methods, compositions, kits, and articles of manufacture related to modulating glucagon receptor pathway.
In one aspect, the invention provides anti-glucagon receptor therapeutic agents suitable for therapeutic use and capable of effecting varying degrees of disruption of the glucagon receptor signaling pathway. For example, the invention provides human antibodies against glucagon receptor, and derivatives and fragments thereof, comprising a sequence of polynucleotides that encode all or a portion of a polypeptide that binds to the glucagon receptor, such as nucleic acid encoding all or part of an anti-glucagon receptor antibody, antibody fragment, or antibody derivative.
In one embodiment, an antibody of the invention is a human antibody that inhibits binding of human glucagon and glucagon receptor. For example, an antibody of the invention inhibits glucagon binding with an IC50 value of less than 1 μM, preferably less than 100 nM, more preferably 10 nM, and most preferably 1 nM. In another embodiment, an antibody of the invention is an antibody that inhibits cAMP signaling dependent on glucagon.
In another embodiment, the present invention provides isolated glucagon receptor specific antibody molecules which comprise heavy and/or light chain variable regions comprising amino acid sequences that are homologous to the corresponding amino acid sequences of the disclosed antibodies, wherein the antibody molecules inhibit glucagon mediated signaling through glucagon receptor. For example, the heavy chain variable domain may comprise a sequence of amino acids that is at least 80, 85, 90, 95, 97 or 99% identical to the sequence of a heavy chain variable domain selected from the group consisting of SEQ ID Nos. 2, 4, 6, 8, 10, 12, 14 and 16. Further, the light chain variable domain may comprise a sequence of amino acids that is at least 80, 85, 90, 95, 97 or 99% identical to the sequence of a light chain variable domain selected from the group consisting of SEQ ID Nos. 18, 20, 22, 24, 26, 28 and 30. Specific embodiments are antagonists which comprise heavy and/or light chain variable regions which are at least 85%, preferably 90%, more preferably 95%, and most preferably 99% homologous to disclosed heavy and/or light chain variable regions, respectively.
In yet another embodiment, the isolated antigen-binding protein comprises a combination of a light chain variable domain and a heavy chain variable domain selected from the group of combinations consisting of a heavy and light chain in SEQ ID Nos. In a specific embodiment, the present invention provides isolated antibody molecules comprising a variant of the heavy and/or light chain variable domain sequences depicted in SEQ ID Nos. 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28 and 30, and conservative modifications thereof. In another embodiment, this invention includes antibodies that can be formed by any combination of the variable domains from each light chain and heavy chain sequence as shown in SEQ ID Nos. 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28 and 30, and equivalents thereof characterized by having one or more conservative amino acid substitutions in any one or more of the CDR sequences, specific embodiments of which inhibit glucagon dependent activation of glucagon receptor signaling pathway.
The invention also provides chimeric molecules comprising glucagon receptor antagonist linked or fused to another, heterologous polypeptide or polymer. For instance, techniques are known for deriving an antibody of a different subclass or isotype from an antibody of interest, i.e., subclass switching. These include a humanized antibody, chimeric antibody, a monoclonal antibody, a polyclonal antibody, a recombinant antibody, an antigen-binding antibody fragment such as F(ab′)2, Fab, Fv, Fab′, Fc, and Fd fragments, and can be incorporated into single domain antibodies, such as single chain antibodies, maxibodies, minibodies, intrabodies, diabodies, triabodies, tetrabodioes, vNAR and bisscFv (Hollinger, P. and Hudson, P. J., 2005, Nat Biotech, 23: 112636).
In additional embodiments, antibodies, fragments, and derivatives of the invention can be fused to other polypeptides or chemicals. The fusion partner can be a peptide, a protein, or a derivative of an antibody that has specific binding activity to other proteins to create bispecific or multispecific molecules or to improve the physiochemical properties of the molecules. In addition, antibodies can be modified to be glycosylated, pegylated, crosslinked, or conjugated to other proteins or chemicals. Amino acids of antibodies can be substituted by non-natural amino acids.
Glucagon receptor antibodies may carry or be conjugated to a toxin, radioactive isotope, radionuclide, a liposome, a targeting moiety, a biosensor, a cationic tail, or an enzyme. Such antagonist compositions form an additional aspect of the present invention.
In some instances, it may be advantageous to have a glucagon receptor antagonist antibody that does not interfere with binding of the ligand (such as glucagon) to the receptor. Accordingly, in one embodiment, the invention provides an antibody that does not bind a glucagon binding site on glucagon receptor. In another embodiment, an antibody of the invention does not substantially inhibit glucagon binding to glucagon receptor. In another embodiment, an antibody of the invention does not substantially compete with glucagon for binding to glucagon receptor.
In another aspect, the invention provides use of a glucagon receptor antagonist antibody of the invention in the preparation of a medicament for the therapeutic and/or prophylactic treatment of a disease, such as diabetes.
In yet another aspect, the invention provides use of an expression vector of the invention in the preparation of a medicament for the therapeutic and/or prophylactic treatment of a disease, such as diabetes.
In a further aspect, the invention provides use of a host cell of the invention in the preparation of a medicament for the therapeutic and/or prophylactic treatment of a disease, such as diabetes.
In still a further aspect, the invention provides use of an article of manufacture of the invention in the preparation of a medicament for the therapeutic and/or prophylactic treatment of a disease, such as diabetes.
The invention also provides pharmaceutical compositions comprising an antibody, or antigen-binding portion thereof, of the invention and a pharmaceutically acceptable carrier. In one embodiment, the pharmaceutical composition further comprises at least one additional therapeutic agent for treating a disorder in which glucagon receptor activation is detrimental.
The antibodies and antigen-binding portions of the invention can be incorporated into pharmaceutical compositions suitable for administration to a subject. Typically, the pharmaceutical composition comprises an antibody or antigen-binding portion of the invention and a pharmaceutically acceptable carrier. As used herein, ‘pharmaceutically acceptable carrier’ includes any and all solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic and absorption delaying agents, and the like that are physiologically compatible. Examples of pharmaceutically acceptable carriers include one or more of water, saline, phosphate buffered saline, dextrose, glycerol, ethanol and the like, as well as combinations thereof. In many cases, it will be preferable to include isotonic agents, for example, sugars, polyalcohols such as mannitol, sorbitol, or sodium chloride in the composition. Pharmaceutically acceptable carriers may further comprise minor amounts of auxiliary substances such as wetting or emulsifying agents, preservatives or buffers, which enhance the shelf life or effectiveness of the antibody or antigen-binding portion.
The compositions of this invention may be in a variety of forms. These include, for example, liquid, semi-solid and solid dosage forms, such as liquid solutions (e.g., injectable and infusible solutions), dispersions or suspensions, tablets, pills, powders, liposomes and suppositories. The preferred form depends on the intended mode of administration and therapeutic application. Typical preferred compositions are in the form of injectable or infusible solutions, such as compositions similar to those used for passive immunization of humans with other antibodies.
The antibodies and antigen-binding portions of the present invention can be administered by a variety of methods known in the art, although for many therapeutic applications, the preferred route/mode of administration is subcutaneous injection, intravenous injection or infusion. As will be appreciated by the skilled artisan, the route and/or mode of administration will vary depending upon the desired results.
Supplementary active compounds can also be incorporated into the compositions. In certain embodiments, an antibody or antigen-binding portion of the invention is coformulated with and/or co-administered with one or more additional therapeutic agents that are useful for treating disorders in which glucagon receptor activation is detrimental. For example, an anti-glucagon receptor antibody or antigen-binding portion of the invention may be co-formulated and/or co-administered with one or more additional antibodies that bind other targets. Furthermore, one or more antibodies of the invention may be used in combination with two or more of therapeutic agents. Such combination therapies may advantageously utilize lower dosages of the administered therapeutic agents, thus avoiding possible toxicities or complications associated with the various monotherapies.
The pharmaceutical compositions of the invention may include a ‘therapeutically effective amount’ or a ‘prophylactically effective amount’ of an antibody or antigen-binding portion of the invention. A ‘therapeutically effective amount’ refers to an amount effective, at dosages and for periods of time necessary, to achieve the desired therapeutic result. A therapeutically effective amount of the antibody or antigen binding portion may vary according to factors such as the disease state, age, sex, and weight of the individual, and the ability of the antibody or antigen-binding portion to elicit a desired response in the individual. A therapeutically effective amount is also one in which any toxic or detrimental effects of the antibody or antigen-binding portion are outweighed by the therapeutically beneficial effects. A ‘prophylactically effective amount’ refers to an amount effective, at dosages and for periods of time necessary, to achieve the desired prophylactic result. Typically, since a prophylactic dose is used in subjects prior to or at an earlier stage of disease, the prophylactically effective amount will be less than the therapeutically effective amount.
An exemplary, non-limiting range for a therapeutically or prophylactically effective amount of an antibody or antigen-binding portion of the invention is 0.01-100 mg/kg, more preferably 0.1-30 mg/kg. It is to be noted that dosage values may vary with the type and severity of the condition to be alleviated. It is to be further understood that for any particular subject, specific dosage regimens should be adjusted over time according to the individual need and the professional judgment of the person administering or supervising the administration of the compositions, and that dosage ranges set forth herein are exemplary only and are not intended to limit the scope or practice of the claimed composition.
Hereinafter, the present invention will be specifically explained with reference to the following examples, which are provided only for the better understanding of the invention, but should not be construed to limit the scope of the invention in any manner.
EXAMPLE 1
Screening of Antibodies that Bind to Glucagon Receptor
HEK293 and CHO cells expressing full length human glucagon receptor with GFP fusion at C-terminus were generated. The stable pool was sorted by FACS and highly fluorescent cells were sorted to enrich cells expressing glucagon receptor in high level.
To generate the protein that encodes the 1st extracellular domain of human glucagon receptor, a mammalian expression vector consisting 1st extracellular domain of human glucagon receptor was fused to the Fc portion of human IgG1 at the C-terminus (NTD-Fc). The construct was transfected into HEK293 cells transiently and the conditioned media was harvested. NTD-Fc fusion protein was purified using protein A agarose beads (Pierce) by affinity purification.
NTD-Fc and cells expressing glucagon receptor were used to pan against phage library displaying scFv of human antibodies. scFv was prepared from human cDNA generated from healthy human beings and displayed on M13 phage using pIII fusion. For panning, purified NTD-Fc was immobilized on protein G magnetic beads (Invitrogen) and bound phages were eluted with triethylamine for the first round. HEK293 cells and CHO cells expressing glucagon receptor with GFP fusion were used in subsequent rounds of panning. After 3 rounds of panning, individual phage clones were examined for its ability to bind NTD-Fc in ELISA. The positive phages were then tested for binding in cell based ELISA in CHO or HEK293 cells expressing glucagon receptor fused to GFP.
EXAMPLE 2
Antibody Conversion and Activity Test
Selected phage clones were sequenced and unique clones were converted into human IgG2 to produce fully human antibodies by transient expression. Conditioned media was harvested and antibodies were purified using protein A agarose beads (Pierce). Various amounts of antibodies were then prepared for cell based ELISA to test its binding ability to human glucagon receptor.
The purified antibodies were then tested for neutralizing activity in cAMP assay using cAMP HTRF kit (CisBio). Various amounts of antibodies were added to the cells expressing glucagon receptor and incubated for 15 minutes before glucagon was added to the cells. Stimulation of glucagon receptor was measured by the amount of cAMP production. Potency of antibody was determined by percentage of inhibition of cAMP production at 100 pM of glucagon stimulation.
EXAMPLE 3
In Vivo Efficacy Test of Antibodies in High Fat Induced Obesity Model
To test the in vivo efficacy of antibodies, Ab7 was transiently expressed and purified. After protein A purification, antibody was quantified and confirmed its activity in cAMP assay.
For high fat diet-induced obesity model, C57BL/6 male mice were acclimated and fed a highfat diet (60% fat by calories; Research Diet) for 6 weeks. On the day of administration, mice were bled for baseline blood glucose measurement, followed immediately with body weight measurement. Mice were sorted into 3 groups (n=9 ̃10 per group) having a similar distribution based on body weight and blood glucose. Mice were then given a single intraperitoneal (IP) injection of vehicle or antibody at 7 mg/kg and 1 mg/kg. Subsequent blood glucose measurements were taken at 1, 2, 3, and 10 days after the single injection.
EXAMPLE 4
Molecular Mechanism of the Antibody Effect Examined by Radioisotope Dilution Method
To gain further insight into the mechanism of glucose lowering effect of the antibody, hepatic and peripheral insulin sensitivity was assessed by radioisotope-labeled glucose infusion (Choi C. S. et al, Proc Natl Acad Sci U-S-A, 2007, 104:16480-85). C57BL/6 male mice were acclimated and fed a high-fat diet (60% fat by calories; Research Diet)for 6 weeks. Seven days before the study, indwelling catheters were placed into the jugular vein. Mice are then given a single intraperitoneal (IP) injection of vehicle or antibody at 7 mg/kg 48h prior to the experiments.
After an overnight fast, [3-3H]-glucose (Perkin Elmer) was infused for 2 hours to assess the basal glucose appearance rate (basal hepatic glucose production). Blood samples (20 μl) were collected at the end of basal period for the measurement of fasting plasma glucose concentration and [3-3H]-glucose activity. Rates of basal whole body glucose appearance were determined as the ratio of the [3-3H]-glucose infusion rate (disintegrations per minute [dpm]) to the specific activity of plasma glucose (dpm per mg) at the end of the basal period.








Sequence Listing Free Text



SEQ ID No. 1 represents the nucleotide sequence of heavy chain variable region


HC1;


 


SEQ ID No. 2 represents the amino acid sequence of heavy chain variable region


HC1;


 


SEQ ID No. 3 represents the nucleotide sequence of heavy chain variable region


HC2;


 


SEQ ID No. 4 represents the amino acid sequence of heavy chain variable region


HC2;


 


SEQ ID No. 5 represents the nucleotide sequence of heavy chain variable region


HC3;


 


SEQ ID No. 6 represents the amino acid sequence of heavy chain variable region


HC3;


 


SEQ ID No. 7 represents the nucleotide sequence of heavy chain variable region


HC4;


 


SEQ ID No. 8 represents the amino acid sequence of heavy chain variable region


HC4;


 


SEQ ID No. 9 represents the nucleotide sequence of heavy chain variable region


HC5;


 


SEQ ID No. 10 represents the amino acid sequence of heavy chain variable region


HC5;


 


SEQ ID No. 11 represents the nucleotide sequence of heavy chain variable region


HC6;


 


SEQ ID No. 12 represents the amino acid sequence of heavy chain variable region


HC6;


 


SEQ ID No. 13 represents the nucleotide sequence of heavy chain variable region


HC7;


 


SEQ ID No. 14 represents the amino acid sequence of heavy chain variable region


HC7;


 


SEQ ID No. 15 represents the nucleotide sequence of heavy chain variable region


HC8;


 


SEQ ID No. 16 represents the amino acid sequence of heavy chain variable region


HC8;


 


SEQ ID No. 17 represents the nucleotide sequence of light chain variable region


LC1;


 


SEQ ID No. 18 represents the amino acid sequence of light chain variable region


LC1;


 


SEQ ID No. 19 represents the nucleotide sequence of light chain variable region


LC2;


 


SEQ ID No. 20 represents the amino acid sequence of light chain variable region


LC2;


 


SEQ ID No. 21 represents the nucleotide sequence of light chain variable region


LC3;


 


SEQ ID No. 22 represents the amino acid sequence of light chain variable region


LC3;


 


SEQ ID No. 23 represents the nucleotide sequence of light chain variable region


LC4;


 


SEQ ID No. 24 represents the amino acid sequence of light chain variable region


LC4;


 


SEQ ID No. 25 represents the nucleotide sequence of light chain variable region


LC5;


 


SEQ ID No. 26 represents the amino acid sequence of light chain variable region


LC5;


 


SEQ ID No. 27 represents the nucleotide sequence of light chain variable region


LC6;


 


SEQ ID No. 28 represents the amino acid sequence of light chain variable region


LC6;


 


SEQ ID No. 29 represents the nucleotide sequence of light chain variable region


LC7; ,


and


 


SEQ ID No. 30 represents the amino acid sequence of light chain variable region


LC7.

## Claims

1. An isolated antibody or an antigen-binding portion thereof for specifically binding to a human glucagon receptor, comprising:
a heavy chain, or a light chain, or both the heavy chain and the light chain, wherein said heavy chain or antigen-binding portion thereof comprises a heavy chain variable region having the amino acid sequence as set forth in SEQ ID No. 12; and said light chain or antigen-binding portion thereof comprises a light chain variable region having the amino acid sequence as set forth in SEQ ID No. 28.

2. The isolated antibody or the antigen-binding portion thereof according to claim 1, which is a monoclonal antibody.

3. The isolated antibody or the antigen-binding portion thereof according to claim 1, wherein the antibody is selected from the group consisting of a human antibody, a humanized antibody, an antigen-binding antibody fragment, a single chain antibody, a diabody, a triabody, a tetrabody, a Fab fragment, a F(ab′)2 fragment, Fd, scFv, a domain antibody, a bispecific antibody, a minibody, a scab, an IgD antibody, an IgE antibody, an IgM antibody, an IgG1 antibody, an IgG2 antibody, an Ig3 antibody, and an IgG4 antibody.

4. A pharmaceutical composition comprising the isolated antibody or the antigen-binding portion thereof according to claim 1, and one or more pharmaceutically acceptable carrier.