PRODUCTION AND CHARACTERIZATION OF MOUSE MONOCLONAL-ANTIBODIES AGAINST AFIPIA-FELIS

A series of 10 monoclonal antibodies reacting with Afipia felis antige ns were selected from mice immunized with li iie organisms of the refe rence strain ATCC 53690. Immunoblotting against SDS-PAGE-separated A. felis sonicate allowed the antibodies to be classified into three grou ps: 1) 168-4, -6, -7 and -10 reacted with a 53 kDa antigen, 2) 168-1, -3 and -9 reacted with both 53 kDa and 60 kDa antigens, and 3) 168-2, -5 and -9 reacted with other antigens. Antibodies of group I did not c ross-react with other Afipia species or 36 unrelated bacteria, whereas those of groups 2 and 3 reacted with other Afipia species and some un related bacteria. Immunoblots of crossed immunoelectrophoretic pattern s of A. Sells sonicate against rabbit antiserum showed that antibodies of groups 1 and 2 bound to the same precipitin arcs. Antibodies of gr oup 1 reacted with a species-specific epitope on the 53 kDa antigen, w hile those of group 2 reacted with other epitopes shared by the 53 kDa and 60 kDa antigens. The binding of antibodies of group 1 to A. felis sonicate was inhibited by post-infection rabbit serum, whereas no inh ibition was observed for antibodies of group 2, The species-specific e pitope of the 53 kDa antigen and the early appearance of antibodies ag ainst this epitope after infection suggest that this antigen can be us ed in a serodiagnostic test for A. felis infection.