BLOCKING OF IRON UPTAKE BY MONOCLONAL-ANTIBODIES SPECIFIC FOR THE NEISSERIA-MENINGITIDIS TRANSFERRIN-BINDING PROTEIN-2

The existence of epitopes common to different strains in the Neisseria meningitidis transferrin (Tf)-binding protein 2 (TBP2), combined with the ability of polyclonal anti-TBP2 antibodies to inhibit Tf binding and block iron uptake in this species, led to this study on the effect of anti-TBP1+2 monoclonal antibodies (MAbs) to determine the presence of epitopes inside the Tf-binding region, All MAbs used reacted exclu sively with the homologous strain when tested by dot-blots of outer me mbrane vesicles, with the reaction being specific for TBP2 after SDS-P AGE and electroblotting, In contrast, ELISA and iron-uptake blocking a ssays were also positive with heterologous strains belonging to Rokbi' s group II (high mol.wt TBP2). The results confirmed the two group cla ssification proposed by Rokbi and, in contrast to other studies, indic ated the existence of epitopes in the Tf-binding region that are commo n only to strains of Rokbi's group II. These epitopes may become denat ured after drying for dot-blot assays or after SDS-PAGE and electroblo tting.