RECOMBINANT RABBIT FAB WITH BINDING-ACTIVITY TO TYPE-1 PLASMINOGEN-ACTIVATOR INHIBITOR DERIVED FROM A PHAGE-DISPLAY LIBRARY AGAINST HUMAN ALPHA-GRANULES

The display of panels of antibody (Ab) fragments on the surface of fil amentous bacteriophage offers a way of making Ab with defined binding specificities. Because rabbit Ab are routinely utilized as immunologic probes in a variety of biological techniques, the aim of this study w as to design and utilize primers for the amplification of mRNAs encodi ng rabbit kappa light and gamma heavy chains for the construction of a n Ab library from this species. Using the polymerase chain reaction, a diverse Ab library with a repertoire of 2 x 10(7) clones was derived from the spleen and bone marrow of a rabbit that had been immunized wi th purified human platelet alpha-granules. From this library, specific clones were isolated after three rounds of affinity selection with bi nding activity to type-1 plasminogen activator inhibitor, a trace prot ein contained in platelet alpha-granules. These data indicate that rec ombinant phage-displayed Ab libraries obtained after immunization with complex biological antigens can be employed for the isolation of rabb it monoclonal Fab against specific antigens contained in the biologica l sample.