CHARACTERIZATION OF O-POLYSACCHARIDE SPECIFIC MONOCLONAL-ANTIBODIES DERIVED FROM MICE INFECTED WITH THE ROUGH BRUCELLA-MELITENSIS STRAIN-B115

Twenty-two monoclonal antibodies (mAbs) specific for smooth lipopolysa ccharide (S-LPS) were generated by fusion of spleen cells from mice in fected with the rough Brucella melitensis strain B115 with the NSO mye loma. According to reactivity in enzyme-linked immunosorbent assay (EL ISA) with O-polysaccharide (O-PS) and absence of reactivity with rough lipopolysaccharide (R-LPS), it was postulated that these mAbs recogni zed epitopes present on the O-PS. Most of the mAbs reacted equally wel l in ELISA and immunoblotting with S-LPS types of Brucella A and M dom inant strains and were designated as specific for common (C) epitopes. Three mAbs were highly specific for M dominant S-LPS. All these mAbs, in contrast to a mAb specific for the A epitope, showed little or no cross-reactivity with Yersinia enterocolitica O:9 S-LPS. S-LPS of B. m elitensis B115 was extracted and analysed by immunoblotting and ELISA with mAbs specific for A, M and C epitopes. Reactivity of the mAbs wit h this S-LPS was compared to reactivity with S-LPS of A and M dominant smooth Brucella strains. The results suggest that S-LPS of B. meliten sis B115 bears mainly C epitopes and a few M epitopes. The very weak r eactivity of this S-LPS with the mAb specific for the A epitope and th e fact that the mAbs specific for C and M epitopes showed little or no cross-reactivity with Y. enterocolitica O:9 S-LPS suggest that O-PS f rom this rough strain could be used to distinguish Y. enterocolitica O :9 infection from Brucella infection. The potential value of the rough B. melitensis strain BI 15 as a vaccine strain is also discussed.