Haemolysin from Mycobacterium avium complex isolates from AIDS patients

Cell-bound haemolytic activity was observed in isolates of Mycobacterium avium complex (MAC) from AIDS patients. M. avium type strains showed negligible activity. None of the culture supernates exhibited any haemolytic activity. Zwitterionic detergent 3-[(3-cholamidopropyl)-dimethyl-ammonio]-1-propanesulphonate (CHAPS) was used to extract haemolysin from ethanol-treated M. avium complex strain 101 (MAC101) cells. Haemolysin was isolated from CHAPS extract (CE) by metal affinity chromatography and identified as a 32-kDa protein by polyclonal antibodies raised against M. tuberculosis haemolysin. Treatment of CE with trypsin resulted in reduction of haemolytic activity, whereas heating at 100°C for 10 min did not affect its activity. A similar 32-kDa haemolysin was extracted from cells of M. avium K128 which was isolated from a monkey infected with simian immunodeficiency virus (SIV). The haemolysin produced by M. avium strains isolated from AIDS patients may be associated with the pathogenesis of M. avium infection.