Heterogeneity of the PorB protein in serotype 22 Neisseria meningitidis

Abstract

The genetic diversity of porB genes from meningococcal isolates characterized as serotype 22 was investigated by gene sequencing. This procedure identified seven distinct porB sequences, demonstrating variation in the PorB protein recognized by the serotype 22 monoclonal antibody. This is consistent with the genetic heterogeneity of serotype 22 meningococci reported previously.

FIG. 1

Alignment of seven meningococcal PorB protein sequences obtained by translation of the nucleotide sequences of each of the porB alleles identified among serotype 22 meningococci. The locations of the putative surface loops (I to VIII) of the porin are indicated. The boxed area defines the putative surface loop VI that is likely to be important for recognition of the PorB proteins by the serotype 22 MAb. Sequences AF065126 and U92906 were different at the nucleotide sequence level but possessed identical peptide sequences.

FIG. 2

Split-decomposition analysis of the seven porB sequences obtained from serotype 22 meningococcal isolates. Split graphs were drawn from Hamming (uncorrected) distance matrices of aligned porB allele sequences by using SplitsTree version 2.4 (8). Branch lengths are drawn to scale.