CD16A Binding Proteins and Use for the Treatment of Immune Disorders

Abstract

CD 16A binding proteins useful for the reduction of a deleterious immune response asre described. In one aspect, humanized anti-cd16A antibodies, optionally lacking effector function, are used for the treatment of immune disorders such as idiopathic thrombocytopenic purpura and autoimme hemolytic anemia.

1 . An anti-CD16A antibody comprising a V H  domain comprising complementarity determining regions (CDRs) derived from the mouse 3G8 antibody heavy chain and a V L  domain comprising CDRs derived from the mouse 3G8 antibody light chain, wherein at least one of said CDRs differs from the corresponding mouse CDR at least one position selected from the group consisting of, in the V H  domain, Val at position 34 in CDR1, Leu at position 50 in CDR2, Phe at position 52 in CDR2, Asn at position 54 in CDR2, Ser at position 60 in CDR2, Ser at position 62 in CDR2, Tyr at position 99 in CDR3, Asp at position 101 of CDR3, and, in the V L  domain, Arg at position 24 in CDR1; Ser at position 25 in CDR1; Tyr at position 32 in CDR1; Leu at position 33 in CDR1; Ala at position 34 in CDR1; Asp, Trp or Ser at position 50 in CDR2; Ala at position 51 in CDR2; Ser at position 53 in CDR2; Ala or Gln at position 55 in CDR2; Thr at position 56 in CDR2; Tyr at position 92 in CDR3; Ser at position 93 in CDR3; and Thr at position 94 in CDR3. 
     
     
         2 - 31 . (canceled) 
     
     
         32 . The antibody of  claim 1  having one to four of said substitutions in each of said V H  and said V L  domains. 
     
     
         33 . The antibody of  claim 1  wherein said antibody does not bind FcγRIII. 
     
     
         34 . The antibody of  claim 1  wherein said antibody does not bind C1q component of complement. 
     
     
         35 . The antibody of  claim 1  that lacks effector function. 
     
     
         36 . The antibody of  claim 35  comprising an Fc region derived from human IgG 1 . 
     
     
         37 . The antibody of  claim 36  wherein said antibody comprises an aglycosyl Fc region. 
     
     
         38 . The antibody of  claim 36  wherein the amino acid corresponding to residue 297 of the Fc region is not asparagine. 
     
     
         39 . The antibody of  claim 36  wherein the amino acid corresponding to residue 297 of the Fc region is glutamine or alanine. 
     
     
         40 . The antibody of  claim 36  wherein the amino acid corresponding to residue 297 of the Fc region is cysteine or cysteine linked to PEG. 
     
     
         41 . The antibody of  claim 36  wherein the amino acid corresponding to residue 299 of the Fc region is not threonine or sesrine. 
     
     
         42 . The antibody of  claim 36  wherein the amino acid corresponding to residue 298 of the Fc region is proline. 
     
     
         43 . The antibody of  claim 1  that is a single chain antibody. 
     
     
         44 . The antibody of  claim 1  that is a tetrameric antibody. 
     
     
         45 . The antibody of  claim 44  that comprises a V H  domain having the sequence of the V H  domain of Hu3G8VH-22. 
     
     
         46 . The antibody of  claim 45  comprising a V L  domain having the sequence of the V L  of Hu3G8VL-1 or Hu3G8VL-43. 
     
     
         47 . The antibody of  claim 1 , that comprises a heavy chain variable region having the sequence of SEQ ID NO:113 and a light chain variable region having the sequence of SEQ ID NO:96, 100, or 118. 
     
     
         48 . A humanized anti-CD16A antibody that lacks effector function and comprises all six complementarity determining regions of mouse antibody 3G8. 
     
     
         49 . The antibody of  claim 48  that comprises a V H  domain comprising an FR3 domain having the sequence of SEQ ID NO:51. 
     
     
         50 . The antibody of  claim 48 , that comprises a heavy chain variable region having the sequence of SEQ ID NO:1.09 or 104 and a light chain variable region having the sequence of SEQ ID NO:96.