A new serogroup (L) of Neisseria meningitidis

Abstract

A strain of N. meningitidis (LCDC 78189) isolated from the mother of a 3 yr old male with meningococcal meningitis was antigenically distinct from the known serogroups A, B, C, D, H, I, K, X, Y, Z, 29E and W135; it was designated serogroup L. Anti-78189 serum specifically agglutinated the homologous strain and 3 other strains which were isolated from the father and 2 other contacts of the child. Only those strains isolated from the contacts produced immunoprecipitates with the anti-78189 serum by the antiserum-agar method. A structurally unique capsular polysaccharide which was obtained from strain 78189 in a highly purified state was the antigen responsible for the serological properties of the strain. The polysaccharide formed a precipitin band with the anti-78189 serum but not with the meningococcal grouping sera; it was also able to absorb the agglutinating and precipitating activity from the anti-78189 serum.