Immunogenicity study on recombinant fHBP of meningococcal group B / 中华微生物学和免疫学杂志

ABSTRACT

Objective:To evaluate the immunogenicity of recombinant factor H binding protein(fHBP) by detecting serum antibody titer and serum bactericidal antibody test (SBA).Methods:fHBP sequence was selected and synthesized, connected to plasmid pET43.1a, transformed to Escherichia coli BL21(DE3), and expressed two recombinant fHBP proteins, included two subfamilies, fHBPA and fHBPB. After purification, the recombinant fHBP proteins were immunized to rabbits and mice. The immune antiserum titer and the bactericidal titer to epidemic strains of meningococcal bacteria group B were measured by ELISA and SBA respectively. Results:The antiserum titer of fHBP immunized rabbits was greater than 2.0×10 6, and that of immunized mice was not less than 1.0×10 6. fHBP immunized rabbit serum had bactericidal titer more than 1∶128 to 41 strains A subfamily and 20 strains B subfamily in the SBA against 69 endemic strains, and there was no cross-protection between the subfamily bacteria. The bactericidal titers of mouse serum immunized fHBPA to strains A subfamily such as Nm210902 Nm211009、Nm450522 were 1∶1 024, 1∶608、1∶861, to Nm510703、Nm311304、Nm431002 were 1∶234、1∶861、1∶430 respectively, and mouse serum immunized fHBP B to strains B subfamily Nm311302、Nm311304、Nm431002 were 1∶876、1∶274、1∶1858, all of three strains were positive in bactericidal titers. Conclusions:the titer of fHBP antiserum was higher than 1.0×10 6, the bactericidal titer was no less than 1∶128 to 61 epidemic strains, and it has a 94.2% protective effect on 69 meningococcal epidemic strains group B.