SEROLOGICAL CROSS-REACTIONS BETWEEN MORAXELLA (BRANHAMELLA) CATARRHALIS AND OTHER OROPHARYNGEAL BACTERIA

Oropharyngeal bacteria belonging to different species were tested for serological cross-reactions with Moraxella catarrhalis using sera from immunized rabbits. Sera were tested using immunofluorescence, an enzy me immunoassay (EIA) and immunoblotting. On immunofluorescence, signif icant cross-reactions were demonstrated with beta-hemolytic streptococ ci group A and group G, as well as with streptococci of the viridans g roup. Some cross-reactions were also noted with Neisseria meningitidis . In the EIA, strong cross-reactions were demonstrated with beta-hemol ytic streptococci. No cross-reactions were obtained with Streptococcus pneumoniae, Haemophilus influenzae or common oral Neisseria. The resu lts are of importance for the interpretation of serological tests to d etect infections with Moraxella catarrhalis, and for the development o f methods for detection of antigens in samples from the respiratory tr act.