Antibodies to BrkA augment killing of Bordetella pertussis

BrkA is a Bvg-regulated Bordetella pertussis protein that mediates serum re sistance and adherence. It shares sequence identity with another B. pertuss is virulence factor called pertactin, and it is a member of the diverse gro up of proteins found in Gram-negative bacteria that are secreted by an auto transporter mechanism. Sera, either from individuals who have been vaccinat ed with acellular pertussis vaccines, or from individuals who have no re-co llection of recent infection with B. pertussis fail to kill wild-type B. pe rtussis, but kill brkA mutant strains very well. We examined whether BrkA c ould be neutralised in serum fitting this profile. BrkA is synthesised as a 103 kDa precursor that is processed into a surface-associated N-terminal 7 3 kDa passenger domain, and an outer-membrane embedded C-terminal 30 kDa tr ansporter moiety. Polyclonal antibodies were raised to a recombinant, re-fo lded histidine-tagged fusion protein representing the 73 kDa passenger regi on. These anti-BrkA antibodies were shown to boost the existing bactericida l capacity of human serum against B. Pertussis by neutralising BrkA. (C) 20 01 Elsevier Science Ltd. All rights reserved.