T-Cell Epitope Mapping the PorB Protein of Serogroup BNeisseria meningitidisin B10 Congenic Strains of Mice

Abstract

T-cell epitope mapping the meningococcal serotype 15 PorB protein performed in this study in three congenic strains of mice with B10 genetic background revealed at least three murine T-cell epitopes (55–72, 163–180, and 226–261), located in the highly conserved putative transmembrane regions of Neisserial porins. Proliferation assays with popliteal lymph node cells derived from mice immunized with the PorB protein or with synthetic 18-mer peptides showed that epitope 163–180 immunized only in the H-2dhaplotype, epitope 55–72 could be presented by both H-2fand H-2smolecules, while the 226–261 region covered by three overlapping peptides could be efficiently recognized in context of all three MHC class II haplotypes studied. Inhibition experiments with blocking I-Aα- and I-Eα-specific mAb showed that peptide 163–180 was presented by I-Adand peptide 244–261 was presented by both I-Afand I-As. In addition, evidence was obtained that peptide 226–243 was presented in context of H-2dor I-Ashaplotypes and peptide 55–72 was presented in context of I-Afand I-Asloci. Finally, the Norwegian outer membrane vesicle vaccine, but not the purified PorB protein, could recall responses in mice immunized with synthetic peptides corresponding to the 226–261 region. Altogether, these results suggest that T-cell epitopes identified on the serotype 15 PorB protein, particularly those presented by several MHC class II molecules (e.g., 226–261), could have important implications for the development of meningococcal vaccines.