SHORT ARTICLES NEUTRALISATION OF IMMUNOLOGICALLY DISTINCT STAPHYLOCOCCAL DELTA HAEMOLYSINS BY ANTIBODIES

PURIFIED b-haemolysin from several canine strains of Staphylococcus aureus give reactions of only partial identity in immunodiffusion test with purified 6-haemolysin from S. aureus strain CN4108 (Newman) and its corresponding rabbit antibodies (Turner, 1978). This raises the question of whether these antibodies to the b-haemolysin of strain CN4108 would neutralise the haemolytic activity of b-haemolysin from the canine strains. Because the 6-haemolysin from both sources was neutralised by a non-immunoglobulin component of normal rabbit serum (Jackson and Little, 1958; Gladstone and Yoshida, 1967; Turner, 1978), it was essential to use only the immunoglobulin fraction of immune sera in this investigation. MATERIALS AND METHODS Purzjication of 6-hamolysin. The purification of 6-haemolysins from strains CN4108 and CN7450 has been described previously (Turner, 1978). The respective activities were 200 and 250 haemolytic units (HU)/mg. Preparation of antisera in rabbits. The immunising schedule was similar to that of Heatley (1977) except that, to save time, the boosting doses were omitted and only the first six of the weekly doses of 6-haemolysin in Freund's complete adjuvant were administered