Evidence for autoimmune antibodies directed against embryonic neural cell adhesion molecules (N-CAM) in patients with group B meningitis.

Human brain tissue shares alpha 2-8 linked polymers of neuraminic acid with the carbohydrates expressed on the capsule of group B Neisseria meningitidis bacteria (Finne et al. (1983) Lancet ii, 355-357; Finne (1985) Trends Biochem. Sci. 10, 129-132; Rougon et al. (1986) J. Cell. Biol. 103, 2429-2437). We report that sera from patients suffering from group B meningitis exhibited IgM antibodies directed against the embryonic, but not the adult, form of neural cell adhesion molecules (N-CAM). These sera also stained live ATt20 cells as well as neuron membranes in mouse embryonic brain cultures. We have demonstrated that such antibodies, directed against carbohydrate moieties of bacterial capsula, were able to lyse cells expressing embryonic N-CAM in a complement-dependent cytotoxic assay. These data infer (1) that humans are able to develop anti-MenB humoral responses, (2) that such responses could initiate autoimmune disorders or be potentially detrimental by interfering with processes mediated by N-CAM interactions, (3) that the development of a vaccine against group B meningitidis should be considered with caution.