Immunization with the Recombinant PorB Outer Membrane Protein Induces a Bactericidal Immune Response against Neisseria meningitidis

Abstract

Infections with Neisseria meningitidis are characterized by life-threatening meningitis and septicemia. The meningococcal porin proteins from serogroup B meningococci have been identified as candidates for inclusion in vaccines to prevent such infections. In this study, we investigated the vaccine potential of the PorB porin protein free of other meningococcal components. The porB gene from a strain of Neisseria meningitidis expressing the class 3 outer membrane porin protein (PorB3) was cloned into the pRSETB vector, and the protein was expressed at high levels in a heterologous host Escherichia coli. The recombinant protein was purified to homogeneity by affinity chromatography and used for immunization after incorporation into liposomes and into micelles composed either of zwitterionic detergent or nondetergent sulfobetaine. The immunogenicity of these preparations was compared to recombinant PorB protein adsorbed to Al(OH) 3 adjuvant as a control. Although sera raised against the protein adsorbed to Al(OH) 3 reacted with the purified recombinant protein, sera raised against liposomes and micelles showed greater activity with native protein, as measured by enzyme immunoassay with outer membranes and by whole-cell immunofluorescence. Reactivity with native protein was considerably enhanced by incorporation of the adjuvant monophosphoryl lipid A into the liposome or micelle preparations. Recognition of the native protein was in a serotype-specific manner and was associated with the ability of the antisera to promote high levels of serotype-specific complement-mediated killing of meningococci. These results demonstrate that the PorB protein should be considered as a component of a vaccine designed to prevent serogroup B meningococcal infection.

The PorB porin from commensal Neisseria lactamica induces Th1 and Th2 immune responses to ovalbumin in mice and is a potential immune adjuvant

“…Both native and recombinant pathogenic neisserial porins have demonstrated to induce similar immune responses, in terms of generation of anti-porin antibodies and bactericidal activity and are considered for a potential antimeningococcal vaccine [28,76,77]. However, potential difficulties in the recombinant porin's expression and structure re-folding or the use of large amounts of pathogenic bacterial cultures (although it could be argued that the use of non-capsulated strains would lower the risks of growing hundred liters of culture), might limit their development as adjuvants.…”

Immunochemical Properties of Recombinant Ompf Porin from Outer Membrane of Yersinia pseudotuberculosis

“…In the case of antibodies against recombinant porins, both in trimeric and in monomeric forms of the proteins were shown to be highly immunogenic in rabbits, even without adjuvants (Elkins et al, 1994), as well as they stimulated the production of bactericidal and diagnostic IgG antibodies in immune stimulating complex (iscom) or vesicles containing components of the OM (Peeters et al, 1999;Wright et al, 2002). In some cases immunization with recombinant porin was shown to induce not only CD4 + T-cells proliferation but the production of IL-12 as well (Shaw et al, 2002).…”

Neisseria meningitidis antigen NMB0088: sequence variability, protein topology and vaccine potential

“…Liposomes have been shown to be an attractive approach as they provide a native-like environment for membrane proteins, particularly with a b-barrel structure (Buchanan, 1999). Several studies with recombinant meningococcal antigens including porins PorA (Christodoulides et al, 1998;Niebla et al, 2001) and PorB (Wright et al, 2002) have clearly demonstrated *Bactericidal titres are represented as the reciprocal of the dilution of antiserum that reduced viable cell count by 50 %. Preimmune sera showed no bactericidal activity (,8).…”