The immune response to a meningococcal 200 kDa surface exposed protein following carriage and disease

Considerable efforts are being made in the search for suitable candidates for an effective serogroup B meningococcal vaccine, but with limited success. We have identified a novel, high molecular weight antigen of approximately 200 kDa. The antigen was expressed during invasive disease as 100% of convalescent case sera contained antibody compared with approximately 50% of carriers. Many clinical isolates did not appear to express the 200 kDa antigen, but corresponding sera contained antibody, indicating in vivo expression. Antibody to this antigen cross-reacted with meningococci of diverse phenotypes. Further investigation of this antigen is required to determine its potential as a future vaccine component.