Chaperonin (MSP63) complexes induce bactericidal and opsonophagocytic cross-reactive antibodies

Alteration of the native structure of antigens can lead to the loss of protective epitopes. Our previous results showed that separation of the meningococcal outer membrane proteins in native conditions revealed the existence of protein complexes that could be relevant for the development of new vaccine formulations. The aim of this work was to analyse the immunogenic characteristics of a highly conserved 700 kDa chaperonin complex (CxChap) detected and purified by using high resolution clear native electrophoresis. Analysis of the anti-CxChap serum by Western-blotting revealed the presence of antibodies against the MSP63 but also against the macrophage infectivity potentiator-like protein (MIP), which is coopurified with the chaperonin complex. Antibodies raised by immunisation with CxChap chaperonin complex show bactericidal and opsonophagocytic activity.