Serotyping of meningococci by coagglutination with monoclonal antibodies.

Treatment of agar-grown meningococci with dilute hydrochloric acid and suspension in saline after washing gave a preparation suitable for meningococcal serotyping by staphylococcal coagglutination with monoclonal antibodies. The monoclonal antibodies available for use and attached to protein A on the staphylococci were directed against the serotype protein antigens 2a, 2b (class 2), 15 (class 3) and the subtype protein antigens P1. 2 and P1. 16 (class 1). Ninety per cent of systemic strains and thirty-four per cent of a collection of carrier isolates, both from Norway late 1981/early 1982, were typable. The serotype antigen 15 alone or in combination with P1. 16 or P1. 16 alone were detected in about 85 per cent of the systemic strains. The quality of the whole-cell meningococcal antigen was important for the test to be easily read.