Common epitopes of pilin of Neisseria meningitidis.

We assessed distribution, immunogenicity, and accessibility of common epitopes of meningococcal pilins. When used as probes in western immunoblots, antisera to gonococcal pili; gonococcal pilin fragment CNBR-2; peptide sequences 41-50, 48-60, and 69-84 of gonococcal pilin; and monoclonal antibody 2-1-Fc recognized meningococcal pilins of different isolates. Meningococcal pilins could be separated into distinct groups based on reactivity with these probes. Common epitopes were conserved on meningococcal pilins isolated during laboratory passage and during infection of human nasopharyngeal organ cultures. Antibodies to common epitopes of pilin were, however, rarely detected in convalescent sera from patients with meningococcal or gonococcal bacteremia. Except for an epitope involving peptide sequence 48-60, immunoelectron microscopy indicated that common epitopes of pilin were not readily accessible on pili assembled on meningococci. Our antisera also did not block attachment of piliated meningococci to human buccal epithelial cells.