Novel Rabbit Antibody Humanization Methods and Humanized Rabbit Antibodies

• US 20090104187A1
• Filed: 05/21/2008
• Published: 04/23/2009
• Est. Priority Date: 05/21/2007
• Status: Abandoned Application

• Current Assignee: AlderBio Holdings, LLC (Lundbeck Seattle Biopharmaceuticals, Inc.)
• Original Assignee: Alder Biopharmaceuticals, Inc. (Lundbeck Foundation)
• Inventors: Kovacevich, Brian R., Latham, John
• Application Number:
  US12/124,723
• Publication Number:
  US 20090104187A1
• Time in Patent Office: Days
• US Class Current: 424/133.100
• CPC Class Codes: A61P 1/02 Stomatological preparations, e.g. drugs for caries, aphtae, periodontitis
• CPC Class Codes: A61P 1/04 for ulcers, gastritis or reflux esophagitis, e.g. antacids, inhibitors of acid secretion, mucosal protectants
• CPC Class Codes: A61P 1/14 Prodigestives, e.g. acids, enzymes, appetite stimulants, antidyspeptics, tonics, antiflatulents
• CPC Class Codes: A61P 11/06 Antiasthmatics
• CPC Class Codes: A61P 17/06 Antipsoriatics
• CPC Class Codes: A61P 19/02 for joint disorders, e.g. arthritis, arthrosis
• CPC Class Codes: A61P 19/10 for osteoporosis
• CPC Class Codes: A61P 25/00 Drugs for disorders of the nervous system
• CPC Class Codes: A61P 25/28 for treating neurodegenerative disorders of the central nervous system, e.g. nootropic agents, cognition enhancers, drugs for treating Alzheimer's disease or other forms of dementia
• CPC Class Codes: A61P 29/00 Non-central analgesic, antipyretic or antiinflammatory agents, e.g. antirheumatic agents; Non-steroidal antiinflammatory drugs [NSAID]
• CPC Class Codes: A61P 3/02 Nutrients, e.g. vitamins, minerals
• CPC Class Codes: A61P 3/04 Anorexiants; Antiobesity agents
• CPC Class Codes: A61P 3/10 for hyperglycaemia, e.g. antidiabetics
• CPC Class Codes: A61P 35/00 Antineoplastic agents
• CPC Class Codes: A61P 35/02 specific for leukemia
• CPC Class Codes: A61P 43/00 Drugs for specific purposes, not provided for in groups A61P1/00-A61P41/00
• CPC Class Codes: A61P 9/00 Drugs for disorders of the cardiovascular system
• CPC Class Codes: A61P 9/10 for treating ischaemic or atherosclerotic diseases, e.g. antianginal drugs, coronary vasodilators, drugs for myocardial infarction, retinopathy, cerebrovascula insufficiency, renal arteriosclerosis
• CPC Class Codes: C07K 16/241 Tumor Necrosis Factors
• CPC Class Codes: C07K 16/248 IL-6
• CPC Class Codes: C07K 16/461 : Igs containing Ig-regions, -domains or -residues form different species
• CPC Class Codes: C07K 2317/20 : characterized by taxonomic origin
• CPC Class Codes: C07K 2317/24 : containing regions, domains or residues from different species, e.g. chimeric, humanized or veneered
• CPC Class Codes: C07K 2317/567 : Framework region [FR]

Abstract

The present invention is directed to novel and improved methods for humanizing rabbit heavy and light variable regions. The resulting humanized rabbit heavy and light chains and antibodies and antibody fragments containing are well suited for use in immunotherapy and immunodiagnosis as they retain the antigen binding affinity of the parent antibody and based on their very high level of sequence identity to human antibody sequences should be essentially non-immunogenic in humans. The invention exemplifies the protocol for the manufacture of therapeutic humanized anti-human TNF-alpha and anti-human IL-6 antibodies.

Claims

1. A humanized antibody or antibody fragment containing at least one heavy and light chain polypeptide wherein the light chain polypeptide is a humanized light chain polypeptide which contains at least the following (i) the amino acid residues spanning the first residue of FR1 through the terminus of FR3 including the CDR 1 and CDR2 regions of a human light chain germline sequence that is selected from a library of human germline sequences based on its greater homology (percent sequence identity) of the selected amino acid residues spanning FR1 through FR3 (relative to other human germline sequences in the library) to the corresponding amino acid residues of the light chain of a parent rabbit antibody having specificity to a desired antigen that is to be humanized and (ii) further wherein the CDR residues in CDR1 and CDR2 corresponding to “

selectivity determining residues”

in the light chain of the same parent rabbit antibody are replaced with the corresponding rabbit selectivity determining residues;

(iii) the amino acid residues encompassing the entire CDR3 region of the same parent rabbit antibody;

(iv) the amino acid residues encompassing the entire FR4 region of an antibody light chain derived from a library of human germline sequences based on its greater homology (sequence identity) to the corresponding FR4 region contained in the light chain of the same parent rabbit antibody; and

(v) wherein few or none of the FR residues of the human FR1, FR2, FR3 and FR4 regions in the selected homologous human FR regions are substituted with the corresponding rabbit FR residues.

2. The humanized antibody claim 1 wherein the parent rabbit antibody is specific to a human, viral or bacterial antigen.

3. The humanized antibody of claim 2 wherein the human antigen is a cytokine, growth factor, hormone or cancer antigen.

4. The humanized antibody of claim 1 which is specific to IL-6, hepcidin, hepatocyte growth factor or a TNF polypeptide.

5. A nucleic acid sequence encoding the humanized antibody light chain contained in the humanized antibody recited in claim 1.

6. vector containing a nucleic acid sequence according to claim 5.

7. A cell containing a vector according to claim 6.

8. The cell of claim 7 which is selected from yeast, bacteria and mammalian cells.

9. The cell of claim 8 which is a diploidal yeast cell.

10. The cell of claim 9 which is a Pichia or other methanol utilizing diploid yeast.

21. The humanized antibody of claim 1 containing at least one humanized light chain polypeptide and further comprising at least one heavy chain polypeptide wherein the at least one heavy chain is a humanized heavy chain polypeptide which contains at least the following (i) the amino acid residues spanning the first residue of FR1 through the terminus of FR3 including the CDR 1 and CDR2 regions encoded by a human germline sequence that is selected from a library of human germline sequences based on its greater homology (percent sequence identity) of the selected amino acid residues spanning FR1 through FR3 (relative to other human germline sequences in the library) to the corresponding amino acid residues of the heavy chain of a parent rabbit antibody having specificity to a desired antigen that is to be humanized and (ii) further wherein the CDR residues in the CDR1 and CDR2 regions of the human heavy chain corresponding to “

selectivity determining residues”

in the CDR1 and CDR2 regions of the heavy chain of the same parent rabbit antibody are replaced with the corresponding heavy chain selectivity determining residues contained in the CDR 1 and CDR2 regions of the rabbit heavy chain;

(iii) the amino acid residues encompassing the entire CDR3 region of the same parent rabbit antibody;

(iv) the FR4 region derived from a library of human germline sequences based on its greater homology (sequence identity) to the corresponding FR4 region contained in the heavy chain of the same parent rabbit antibody; and

(v) wherein the final 1-3 amino acids of the human heavy FR1 region are optionally replaced with the terminal 1-3 amino acids of the corresponding rabbit heavy chain FR1 residues; and

/or the terminal amino acid of the human heavy chain framework 2 region is optionally replaced with the corresponding terminal amino acid residue of the rabbit heavy chain framework 2; and

/or the fourth amino acid from the terminus of the rabbit heavy chain CDR2 (typically a tryptophan) is optionally replaced with the corresponding human CDR2 residue (typically a serine); and

(vi) wherein few or none of the remaining FR residues of the selected homologous human FR regions are substituted with the corresponding rabbit FR residues.

22. The humanized antibody of claim 21 which is specific to IL-6, hepcidin, hepatocyte growth factor or a TNF polypeptide.

72. A method of immunotherapy or immunodiagnosis which comprises the administration of a humanized antibody wherein the improvement comprises administering a humanized antibody or antibody fragment according to claim 1.

73. The method of claim 72 which comprises ameliorating or reducing symptoms of a disease or disorder associated with IL-6, or TNF.

74. The method of claim 73, wherein said disease or disorder associated with IL-6 or TNF-alpha is cancer or an inflammatory condition.

75. The method of claim 73 wherein the antibody is an anti-IL-6 antibody and is used to treat or diagnose the prognosis of IL-6 associated fatigue, cachexia or arthritis.

76. The method of claim 73, wherein said disease or disorder associated with IL-6 is selected from general fatigue, exercise-induced fatigue, cancer-related fatigue, inflammatory disease-related fatigue, chronic fatigue syndrome, cancer-related cachexia, cardiac-related cachexia, respiratory-related cachexia, renal-related cachexia, age-related cachexia, rheumatoid arthritis, systemic lupus erythematosis (SLE), systemic juvenile idiopathic arthritis, psoriasis, psoriatic arthropathy, ankylosing spondylitis, inflammatory bowel disease (IBD), polymyalgia rheumatica, giant cell arteritis, autoimmune vasculitis, graft versus host disease (GVHD), Sjogren'"'"'s syndrome, adult onset Still'"'"'s disease, rheumatoid arthritis, systemic juvenile idiopathic arthritis, osteoarthritis, osteoporosis, Paget'"'"'s disease of bone, osteoarthritis, multiple myeloma, Hodgkin'"'"'s lymphoma, non-Hodgkin'"'"'s lymphoma, prostate cancer, leukemia, renal cell cancer, multicentric Castleman'"'"'s disease, ovarian cancer, drug resistance in cancer chemotherapy, cancer chemotherapy toxicity, ischemic heart disease, atherosclerosis, obesity, diabetes, asthma, multiple sclerosis, Alzheimer'"'"'s disease and cerebrovascular disease.

77. The method of claim 73, wherein said disease or disorder is associated with TNF and is selected from general fatigue, exercise-induced fatigue, cancer-related fatigue, inflammatory disease-related fatigue, chronic fatigue syndrome, cancer-related cachexia, cardiac-related cachexia, respiratory-related cachexia, renal-related cachexia, age-related cachexia, rheumatoid arthritis, systemic lupus erythematosis (SLE), systemic juvenile idiopathic arthritis, psoriasis, psoriatic arthropathy, ankylosing spondylitis, inflammatory bowel disease (IBD), polymyalgia rheumatica, giant cell arteritis, autoimmune vasculitis, graft versus host disease (GVHD), Sjogren'"'"'s syndrome, adult onset Still'"'"'s disease, rheumatoid arthritis, systemic juvenile idiopathic arthritis, osteoarthritis, osteoporosis, Paget'"'"'s disease of bone, osteoarthritis, multiple myeloma, Hodgkin'"'"'s lymphoma, non-Hodgkin'"'"'s lymphoma, prostate cancer, leukemia, renal cell cancer, multicentric Castleman'"'"'s disease, ovarian cancer, drug resistance in cancer chemotherapy, cancer chemotherapy toxicity, ischemic heart disease, atherosclerosis, obesity, diabetes, asthma, multiple sclerosis, Alzheimer'"'"'s disease and cerebrovascular disease.

78. The method of claim 72 wherein the humanized antibody or antibody fragment is expressed in a polyploid yeast culture that stably expresses and secretes into the culture medium at least 10-25 mg/liter of said antibody, comprising:

(i) introducing at least one expression vector containing one or more heterologous polynucleotides encoding said humanized antibody or fragment operably linked to a promoter and a signal sequence into a haploid yeast cell;

(ii) producing by mating or spheroplast fusion a polyploidal yeast from said first and/or second haploid yeast cell;

(iii) selecting polyploidal yeast cells that stably express said humanized antibody or fragment; and

(iv) producing stable polyploidal yeast cultures from said polyploidal yeast cells that stably express at least 10-25 mg/liter of said humanized antibody or fragment into the culture medium.

79. The method of claim 78, wherein said yeast is selected from the following genera:

Arxiozyma;

Ascobotryozyma;

Citeromyces;

Debaryomyces;

Dekkera;

Eremothecium;

Issatchenkia;

Kazachstania;

Kluyveromyces;

Kodamaea;

Lodderomyces;

Pachysolen;

Pichia;

Saccharomyces;

Saturnispora;

Tetrapisispora;

Torulaspora;

Williopsis; and

Zygosaccharomyces.

80. The method of claim 79, wherein said yeast genera is Pichia.

81. The method of claim 80, wherein the species of Pichia is selected from Pichia pastoris, Pichia methanolica and Hansenula polymorpha (Pichia angusta).

89. A vector that expresses a humanized rabbit according to claim 1.

90. A host cell comprising the vector of claim 89.

91. The host cell of claim 90, wherein said host cell is a yeast cell belonging to the genus Pichia.

11. A humanized antibody or antibody fragment containing at least one heavy chain and light chain polypeptide wherein the heavy chain is a humanized heavy chain polypeptide which contains at least the following (i) the amino acid residues spanning the first residue of FR1 through the terminus of FR3 including the CDR1 and CDR2 regions encoded by a human germline sequence that is selected from a library of human germline sequences based on its greater homology (percent sequence identity) of the selected amino acid residues spanning FR1 through FR3 (relative to other human germline sequences in the library) to the corresponding amino acid residues of the heavy chain of a parent rabbit antibody having specificity to a desired antigen that is to be humanized and (ii) further wherein the CDR residues in the CDR 1 and CDR2 regions of the human heavy chain corresponding to “

selectivity determining residues”

in the CDR 1 and CDR2 regions of the heavy chain of the same parent rabbit antibody are replaced with the corresponding heavy chain selectivity determining residues contained in the CDR1 and CDR2 regions of the rabbit heavy chain;

(iii) the amino acid residues encompassing the entire CDR3 region of the same parent rabbit antibody;

(iv) the FR4 region derived from a library of human germline sequences based on its greater homology (sequence identity) to the corresponding FR4 region contained in the heavy chain of the same parent rabbit antibody; and

(v) wherein the final 1-3 amino acids of the human heavy FR1 region are optionally replaced with the terminal 1-3 amino acids of the corresponding rabbit heavy chain FR1 residues; and

/or the terminal amino acid of the human heavy chain framework 2 region is optionally replaced with the corresponding terminal amino acid residue of the rabbit heavy chain framework 2; and

/or the fourth amino acid from the terminus of the rabbit heavy chain CDR2 (typically a tryptophan) is optionally replaced with the corresponding human CDR2 residue (typically a serine); and

(vi) wherein few or none of the remaining FR residues of the selected homologous human FR regions are substituted with the corresponding rabbit FR residues.

12. The humanized antibody of claim 11 wherein the parent rabbit antibody is specific to a human, viral or bacterial antigen.

13. The humanized antibody of claim 12 wherein the human antigen is a cytokine, growth factor, hormone or cancer antigen.

14. The humanized antibody of claim 11 which is specific to IL-6, hepcidin, hepatocyte growth factor or a TNF polypeptide.

15. A nucleic acid sequence encoding the humanized antibody heavy chain contained in the humanized antibody of claim 12.

16. A vector containing a nucleic acid sequence according to claim 15.

17. A cell containing a vector according to claim 16.

18. The cell of claim 17 which is selected from yeast, bacteria and mammalian cells.

19. The cell of claim 18 which is a diploidal yeast cell.

20. The cell of claim 19 which is a Pichia or other methanol utilizing diploid yeast.

23. A humanization strategy for producing a humanized light chain antibody sequence comprising the following steps:

(i) obtaining a DNA encoding rabbit light chain antibody sequence from a rabbit antibody that specifically binds to a desired antigen and identifying the amino residues spanning the beginning of Framework 1 (FR1) to the end of Framework 3 (FR3) inclusive;

(ii) conducting a homology search using said rabbit light antibody amino acid sequence spanning the beginning of FR1 to the end of FR3 sequence against a library containing human light chain antibody sequences and identifying a human light chain antibody sequence that exhibits substantial sequence homology thereto relative to other human germline antibody light chain sequences;

(iii) identifying in both the rabbit and human light chain sequences the arrangement and the specific residues thereof that correspond to FR1. FR2, FR3, CDR1, CDR2 regions and aligning these discrete regions in the rabbit and selected human antibody light chain;

(iv) constructing a DNA or amino acid sequence wherein the CDR 1 and CDR2 regions of the selected homologous human light chain sequence are substituted by the corresponding selectivity determining residues contained in the CDR 1 and CDR2 regions of the rabbit light chain sequence;

(v) further attaching to the DNA or amino acid sequence obtained by step (iv) a DNA sequence encoding or polypeptide containing the corresponding amino acid residues of the rabbit CDR3 light chain antibody sequence;

(vi) further selecting a human light chain framework 4 region (FR4) that is homologous to the FR4 contained in the rabbit light chain and which preferably differs therefrom by at most 2-4 amino acid residues and attaching a DNA sequence encoding said human FR4 or the corresponding amino residues of said human FR4 onto the DNA or amino acid sequence obtained after step (v); and

(vii) synthesizing a DNA or amino acid sequence encoding or containing the humanized rabbit light chain sequence that results from steps (i) through (vi).

24. The humanization strategy of claim 23 wherein the amino acid initiating FR1 is the first amino acid after the rabbit light chain signal sequence.

25. The humanization strategy of claim 23 wherein the signal sequence comprises about 20-22 amino acid residues.

26. The humanization strategy of claim 23 wherein the human light chain sequence is identified from a library containing human germline variable light chain sequences.

27. The humanization strategy of claim 23 wherein the FR1, FR2, FR3 and CDR1 and CDR2 regions in the rabbit sequence are identified by aligning the rabbit FR1, FR2, FR3 and CDR1 and CDR2 regions with the corresponding human light chain FR1, FR2, FR3, CDR1 and CDR2 regions.

28. The humanization strategy of claim 23 wherein the rabbit CDR3 region comprises from 9 to 15 amino acid residues.

29. The humanization strategy of claim 23 wherein the rabbit light chain FR4 region comprises 11 amino acid residues.

30. The humanization strategy of claim 23 wherein FR3 ends with YYC.

31. The humanization strategy of claim 23 wherein the FR4 in the rabbit light chain starts with FGGGG.

32. The humanization strategy of claim 31 wherein said rabbit FR4 region starts with a VVKR amino acid sequence.

33. The humanization strategy of claim 23 wherein the selected human FR4 light chain sequence comprises FGGGTKVEIKR.

34. The humanization strategy of claim 23 wherein the resultant humanized rabbit light chain is used in the manufacture of a humanized antibody or humanized antibody fragment that binds a desired antigen.

35. A humanized rabbit light chain variable amino acid sequence or a DNA encoding produced according to claim 23.

36. The humanized rabbit light chain variable amino acid sequence or DNA sequence of claim 35 which is specific to an antigen selected from a microbial antigen, a human antigen, viral antigen, and an allergen.

37. The humanized rabbit light chain variable amino acid or DNA sequence of claim 36 wherein the human antigen is selected from a human autoantigen, cytokine, receptor protein, enzyme, hormone, receptor ligand, steroid, growth factor and an oncogene.

38. An antibody or antibody fragment containing a humanized rabbit light chain variable sequence produced according to claim 23.

39. The humanized rabbit light chain or antibody containing produced according to claim 23 which is attached to an effector moiety.

40. The humanized rabbit light chain polypeptide of claim 39 wherein the effector moiety is selected from a drug, a toxin, an enzyme, a radionuclide, a fluorophore, a cytokine, an affinity label, and a translocating polypeptide.

41. The humanized rabbit light chain polypeptide or antibody containing or a DNA encoding produced according to claim 23 which is derived from a rabbit antibody that specifically binds a cytokine, growth factor or a tumor specific polypeptide.

42. The humanized rabbit light chain polypeptide or antibody containing of claim 41 that is derived from a rabbit antibody that specifically binds IL-6, TNF, VEGF, IL-12, Hepcidin or Hepatocyte growth factor.

68. A humanized rabbit antibody comprising at least one humanized rabbit light chain produced according to at least one of claims 23-34 and at least one humanized rabbit heavy chain produced according to claim 43.

69. The humanized rabbit antibody of claim 68 which comprises human constant domains.

70. The humanized rabbit antibody of claim 69 which is selected from an IgG1, IgG2, IgG3 and IgG4.

71. The humanized rabbit antibody of claim 68 which binds an antigen selected from a human antigen, bacterial antigen, viral antigen, pathogen, parasite, yeast antigen and a fungal antigen.

43. A humanization strategy for producing a humanized heavy chain antibody sequence from a rabbit heavy chain antibody sequence comprising the following steps:

(i) obtaining a rabbit heavy chain antibody sequence from an rabbit antibody that specifically binds to a desired antigen and identifying the amino residues spanning the beginning of Framework 1 (FR1) to the end of Framework 3 (FR3) inclusive;

(ii) conducting a homology search (e.g., by BLAST searching of human germline antibody sequence containing libraries) using said rabbit heavy antibody amino acid sequence spanning the beginning of FR1 to the end of FR3 sequence and identifying a human heavy chain antibody sequence that is homologous thereto, i.e. which preferably possesses at least 80%-90% identical thereto at the amino acid level;

(iii) identifying in both the rabbit and human heavy chain sequences the arrangement of and the specific residues thereof that correspond to FR1, FR2, FR3, CDR1, CDR2 regions and aligning these discrete regions of the rabbit against the corresponding regions of the selected homologous human antibody heavy chain;

(iv) constructing a DNA or amino acid sequence wherein the residues in the CDR1 and CDR2 regions of the selected homologous human heavy chain sequence are substituted by the selectivity determining residues contained in the corresponding CDR1 and CDR2 regions of the rabbit heavy chain sequence and optionally replacing the terminal 1-3 amino acids of the human heavy FR1 region with the corresponding terminal 1-3 amino acids of the rabbit heavy chain FR1; and

/or optionally replacing the terminal amino acid of the human heavy chain framework 2 region with the corresponding terminal amino acid residue of the rabbit heavy chain framework 2 and/or optionally replacing the fourth amino acid from the terminus of the rabbit heavy chain CDR2 (typically a tryptophan) with the corresponding human CDR2 residue (typically a serine);

(v) further attaching to the DNA or amino acid sequence obtained by step (iv) a DNA sequence encoding or having the corresponding amino acid residues of the rabbit heavy chain CDR3 which is contained in the same rabbit heavy chain antibody sequence;

(vi) further selecting a human heavy chain framework 4 region (FR4) that is homologous thereto (preferably differs from the FR4 contained in the humanized rabbit antibody heavy chain sequence by at most 4 amino acid residues) and attaching a DNA sequence encoding said selected homologous human FR4 or the corresponding amino residues of said human FR4 onto the DNA or amino acid sequence obtained after step (v)); and

(vii) synthesizing a DNA or amino acid sequence encoding or containing the humanized rabbit heavy chain sequence that results from steps (i) through (vi).

44. The humanization strategy of claim 43 wherein the amino acid initiating FR1 is the first amino acid after the rabbit heavy chain signal sequence.

45. The humanization strategy of claim 43 wherein the end of FR3 is about 95-100 amino acid residues after the first residue of FR1.

46. The humanization strategy of claim 43 wherein the signal sequence comprises no more than 19 amino acid residues.

47. The humanization strategy of claim 43 wherein the homologous human heavy chain sequence is identified by a BLAST search of human germline sequences obtained prior to antibody maturation.

48. The humanization strategy of claim 43 wherein the selected homologous human heavy chain possesses at least 90-95% sequence identity to the corresponding region of the rabbit heavy chain.

49. The humanization strategy of claim 43 wherein the FR1, FR2, FR3 and CDR 1 and CDR2 regions in the rabbit heavy chain sequence are identified by aligning the rabbit FR1, FR2, FR3 and CDR 1 and CDR2 regions with the corresponding human heavy chain FR1, FR2, FR3, CDR1 and CDR2 regions.

50. The humanization strategy of claim 43 wherein the final 3 amino acid residues of the human FR1 are replaced with the corresponding 3 residues of the rabbit FR1.

51. The humanization strategy of claim 50 wherein the 3 residues in rabbit FR1 are preceded by ser-gly.

52. The humanization strategy of claim 43 which further comprises replacing the terminal amino acid residue of the human FR2 with the corresponding terminal amino acid residue of rabbit FR2.

53. The humanization strategy of claim 52 wherein the terminal rabbit FR2 residue comprises a glycine optionally preceded by a isoleucine residue.

54. The humanization strategy of claim 43 which further comprises changing the tryptophan residue that is located about 4 residues from the end of the rabbit CDR2 with a serine residue.

55. The method of claim 43 wherein the rabbit CDR3 comprises 5-19 amino acid residues.

56. The humanization strategy of claim 43 wherein the rabbit CDR3 is followed by the residues WG″

X″

G, where “

X”

is preferably Q or P.

57. The humanization strategy of claim 43 wherein the rabbit FR4 comprises 11 amino acid residues.

58. The humanization strategy of claim 57 wherein the rabbit FR4 comprises WGQGTLVTVSS.

59. The humanized rabbit heavy chain variable amino acid sequence or DNA sequence produced by claim 43 which is derived from a rabbit antibody specific to an antigen selected from a microbial antigen, a human antigen, viral antigen, and an allergen.

60. The humanized rabbit heavy chain variable amino acid sequence or DNA sequence of claim 59 which is specific to a human antigen.

61. The humanized rabbit heavy chain variable amino acid or DNA sequence of claim 59 wherein the human antigen is selected from a human autoantigen, cytokine, receptor protein, enzyme, hormone, receptor ligand, steroid, growth factor and an oncogene.

62. An antibody or antibody fragment containing a humanized rabbit heavy chain variable sequence produced according to claim 43.

63. The humanized rabbit heavy chain produced according to claim 43 which is attached to an effector moiety.

64. The humanized rabbit heavy chain polypeptide of claim 63 wherein the effector moiety is selected from a drug, a toxin, an enzyme, a radionuclide, a fluorophore, a cytokine, an affinity label, and a translocating polypeptide.

65. The humanized rabbit heavy chain polypeptide or a DNA encoding produced according to claim 43. which is derived from a rabbit antibody that specifically binds a cytokine, growth factor or a tumor specific polypeptide.

66. The humanized rabbit heavy chain polypeptide of claim 65 that is derived from a rabbit antibody that specifically binds IL-6, TNF-alpha, VEGF-alpha, IL-12, Hepcidin or Hepatocycle growth factor.

67. The humanized rabbit heavy chain polypeptide of claim 64 which is aglycosylated.

82. A humanized antibody or antibody fragment containing a humanized antibody polypeptide produced by claim 43.

wherein said humanized antibody or fragment binds to an antigen with a dissociation constant (K_D) of less than or equal to 5×

10<sup>−

7</sup> M<sup>−

1</sup>, 10<sup>−

7</sup> M<sup>−

1</sup>, 5×

10<sup>−

8</sup> M<sup>−

1</sup>, 10<sup>−

8</sup> M<sup>−

1</sup>, 5×

10<sup>−

9</sup> M<sup>−

1</sup>, 10<sup>−

9</sup> M<sup>−

1</sup>, 5×

10<sup>−

10</sup> M<sup>−

1</sup>, 10<sup>−

10</sup> M<sup>−

1</sup>, 5×

10<sup>−

11</sup> M<sup>−

1</sup>, 10<sup>−

11</sup> M<sup>−

1</sup>, 5×

10<sup>−

12</sup> M<sup>−

1</sup>, 10<sup>−

12</sup> M<sup>−

1</sup>, 5×

10<sup>−

13</sup> M<sup>−

1</sup>, 10<sup>−

13</sup> M<sup>−

1</sup>, or 5×

10<sup>−

14</sup> M<sup>−

1</sup>.

83. The humanized antibody of claim 82, wherein said antibody binds to an antigen with a dissociation constant (K_D) of less than or equal to 5×

10<sup>−

10</sup> M<sup>−

1</sup>.

84. The humanized antibody of claim 82, wherein said antibody binds to an antigen with an off-rate (K_off) of less than or equal to 10⁻

4 S<sup>−

1</sup>, 5×

10<sup>−

5</sup> S<sup>−

1</sup>, 10<sup>−

5</sup> S<sup>−

1</sup>, 5×

10<sup>−

6</sup> S<sup>−

1</sup>, 10<sup>−

6</sup> S<sup>−

1</sup>, 5×

10<sup>−

7</sup> S<sup>−

1</sup>, or 10<sup>−

7</sup> S<sup>−

1</sup>.

85. The humanized antibody of claim 82, wherein the parent rabbit antibody originated from one or more rabbit B cell populations.

86. The humanized antibody of claim 82 wherein said antibody inhibits the association of IL-6 with IL-6R or TNF and its receptor.

87. The humanized antibody of claim 86, wherein the IL-6R is soluble IL-6R (sIL-6R).

88. The humanized antibody of claim 86, wherein the TNF receptor (TNFR) is soluble.