SERUM RESISTANCE IN BVG-REGULATED MUTANTS OF BORDETELLA-PERTUSSIS

Serum resistance, or resistance to killing by antibody dependent pathw ay of complement, in Bordetella pertussis is bvg-regulated and the Bor detella resistance to killing (brk) locus mediates much of the resista nce. Here we examined whether other bvg-regulated proteins contribute to serum resistance. We found that neither pertussis toxin, adenylate cyclase toxin, filamentous hemagglutinin, dermonecrotic toxin, trachea l colonization factor, nor Vag8 mutants were sensitive to serum killin g compared to the wild-type. Filamentous hemagglutinin has been report ed to bind C4 binding protein, an inhibitor of complement, but this ac tivity does not appear to contribute to serum resistance, as evidenced by the resistant phenotype of FHA mutants. Clinical isolates were ser um resistant and wild-type strains possessing an additional copy of th e brk locus were 2-5-fold more resistant to serum killing. (C) 1998 Fe deration of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.