THE BACTERICIDAL ACTION OF HUMAN SERUM ON HEMOLYTIC STREPTOCOCCI : II. FACTORS WHICH INFLUENCE THE PHENOMENON IN VITRO.

Although sera derived from patients at the time of acute, active infection were found to be capable of destroying hemolytic streptococci under aerobic conditions, the organisms retained viability when the tests were performed in the environment of anaerobiosis afforded by a vaseline seal or an anaerobic jar. Within the limitations of the experimental procedures which were employed, the aerobic or anaerobic effect was found to be a reversible reaction. Heating sera at 60 degrees C. for 1 hour inactivated the streptococcidal element in most instances, but not in every case; heating at 56 degrees C. for 1 hour impaired the killing power of half of the specimens which were tested. Sera retained the capacity to destroy hemolytic streptococci when kept in the ice box for 3 weeks; a slight diminution in killing power was noted after 4 weeks. By the methods which were employed, the streptococcidal property of sera could not be correlated with either true antibacterial agglutination or with pseudo-agglutination. The significance of the findings as a basis for analyzing the mechanism of the streptococcidal phenomenon is discussed.