Production of anti-self antibodies from antibody segment repertoires and displayed on phage

Abstract

Methods are disclosed for the production of anti-self antibodies and antibody fragments, being antibodies or fragments of a particular species of mammal which bind self antigens of that species. Methods comprise providing a library of replicable genetic display packages (rgdps), such as filamentous phage, each rgdp displaying at its surface member of a specific binding pair which is an antibody or antibody fragment, and each rgdp containing nucleic acid sequence derived from a species of mammal. The nucleic acid sequence in each rgdp encodes a polypeptide chain which is a component part of the sbp member displayed at the surface of that rgdp. Anti-self antibody fragments are selected by binding with a self antigen from said species of mammal. The displayed antibody fragments may be scFv, Fd, Fab or any other fragment which has the capability of binding antigen. Nucleic acid libraries used may be derived from rearranged V-gene sequences of unimmunised mammal. Synthetic or artificial libraries are described and shown to be useful.

1 . A method of obtaining a member of a specific binding pair (sbp member), the sbp member being an antibody or antibody fragment and having an antigen binding site with binding specificity for an antigen which is a self antigen of a species of mammal, the method comprising: 
 (a) providing a library of replicable genetic display packages (rgdps), each rgdp displaying at its surface an sbp member, and each rgdp containing nucleic acid with sequence derived from said species of mammal and encoding a polypeptide chain which is a component part of the sbp member displayed at the surface of that rgdp;    (b) selecting, by binding with said self antigen, one or more sbp members with binding specificity for said self antigen.    
     
     
         2 . A method according to  claim 1  wherein each said sbp member displayed at the surface of an rgdp is an antibody fragment comprising a VH domain and a VL domain.  
     
     
         3 . A method according to  claim 2  wherein each said sbp member displayed at the surface of an rgdp is an scFv antibody fragment.  
     
     
         4 . A method according to  claim 2  wherein each said sbp member displayed at the surface of an rgdp is a Fab antibody fragment.  
     
     
         5 . A method according to  claim 1  wherein the nucleic acid is derived from rearranged V genes of an unimmunised mammal.  
     
     
         6 . A method according to  claim 1  wherein the nucleic acid is derived from a library prepared by artificial or synthetic recombination of V gene sequences.  
     
     
         7 . A method according to  claim 6  wherein the library is derived from germ line V-gene sequences.  
     
     
         8 . A method according to  claim 1  wherein said species of mammal is human.  
     
     
         9 . A method according to  claim 1  wherein sbp members selected in (b) displayed at the surface of rgdps are selected or screened to provide an individual rgdp displaying an sbp member or a mixed population of said rgdps, with each rgdp containing nucleic acid encoding the sbp member or a polypeptide chain thereof which is displayed at its surface.  
     
     
         10 . A method according to  claim 9  wherein nucleic acid which encodes a selected or screened sbp member and which is derived from an rgdp which displays at its surface a selected or screened sbp member is used to express an sbp member or a fragment or derivative thereof in a recombinant host organism.  
     
     
         11 . A method according to  claim 10  wherein nucleic acid from one or more rgdps is taken and used to provide encoding nucleic acid in a further method to obtain an individual sbp member or a mixed population of sbp members, or encoding nucleic acid therefor.  
     
     
         12 . A method according to  claim 10  wherein the expression end product is modified to produce a derivative thereof.  
     
     
         13 . A method according to  claim 10  wherein the expression end product or derivative thereof is used to prepare a therapeutic or prophylactic medicament or a diagnostic product.