A member of a specific binding pair (sbp) is identified by expressing DNA encoding
a genetically diverse population of such sbp members in recombinant host cells
in which the sbp members are displayed in functional form at the surface of a secreted
recombinant genetic display package (rgdp) containing DNA encoding the sbp member
or a polypeptide component thereof, by virtue of the sbp member or a polypeptide
component thereof being expressed as a fusion with a capsid component of the rgdp.
The displayed sbps may be selected by affinity with a complementary sbp member,
and the DNA recovered from selected rgdps for expression of the selected sbp members.
Antibody sbp members may be thus obtained, with the different chains thereof expressed,
one fused to the capsid component and the other in free form for association with
the fusion partner polypeptide. A phagemid may be used as an expression vector,
with said capsid fusion helping to package the phagemid DNA. Using this method
libraries of DNA encoding respective chains of such multimeric sbp members may
be combined, thereby obtaining a much greater genetic diversity in the sbp members
than could easily be obtained by conventional methods.
