Development and evaluation of scheme for serotyping Gardnerella vaginalis

Antibodies to Gardnerella vaginalis were raised in rabbits. Nine antisera that reacted with their immunising strains, but not with the remaining eight strains, were used to develop a serotyping scheme. A dot blotting technique was used, and complexes of antigen and antibody were visualised using anti-rabbit immunoglobulin linked to alkaline phosphatase. Of 91 clinical isolates used to evaluate the scheme, 79 (87%) were typable and 52 (57%) reacted with only a single antiserum. The antigens expressed were stable during growth on different media and on subculture. The specificity of the antibody was shown to be directed against different immunodominant proteins and possibly a carbohydrate.