Immunogenicity of in vitro folded outer membrane protein PorA of Neisseriameningitidis

In vitro folded and the denatured form of PorA P1.6 From Neisseria meningit idis strain M990 were used for immunization studies in mice. previously. th e antigen was isolated from cytoplasmic inclusion bodies, folded and purifi ed. Its immunogenicity without adjuvant appeared to be low. The addition of the adjuvant QuilA, but not of galE lipooligosaccharide, considerably enha nced the immunogenicity. Moreover, when immunized with folded PorA P1.6 plu s QuilA, a clear switch towards the IgG2a subclass of antibodies and concom itantly, the appearance of serum bactericidal activity, which is believed t o be important for protective immunity, was observed. Hence, a tool for pre paring vaccines against serogroup B meningococci devoid of endotoxin is ava ilable. (C) 2000 Federation of European Microbiological Societies. Publishe d by Elsevier Science B.V. All rights reserved.