Antigenic diversity of Neisseria meningitidis isolated in Taiwan between 1995 and 2002.

The geographic distribution of N. meningitidis is diverse. Information on the antigenic variation of N. meningitidis is important for the development of an outer membrane protein-based vaccine. As a first step towards vaccine development, serological typing was performed to determine the antigenic properties of 127 invasive N. meningitidis isolates collected in Taiwan between 1995 and 2002. With 31.5% non-serotypeable and 32.3% non-serosubtypeable, the 127 isolates fell into 51 phenotypes, with W135:NT:P1.5,2:L3,7,9, Y:14P1.5,2, and B:1:NST:L3,7,9 being the 3 most prevalent. Among the 37 serogroup B isolates, 15 serosubtypes were found, with P1.5,2 and P1.12,13 being the most prevalent. The high diversity of Por A among serogroup B isolates circulating in Taiwan poses a great challenge for the development of a PorA-based vaccine. Because 85% of the serogroup B isolates had the L3,7,9 immunotype, inclusion of L3,7,9 lipooligosaccharides in a PorA-based vaccine may be a promising approach. In addition, based on the phenotypic characterization, we suggest that both serogroup B and W135 isolates were endemic and that serogroup A, C, and Y isolates were imported, which may reflect increased international travel.