NATURE OF CYTOTOXIC REACTIONS MEDIATED BY ANTIBODY AND COMPLEMENT, AND RELATED PHENOMENA.
Semi-annual rept. for 1 Jul-31 Dec 52,
JOHNS HOPKINS UNIV BALTIMORE MD SCHOOL OF HYGIENE AND PUBLIC HEALTH
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It has been possible to distinguish and physically separate two stages in the lysis of sensitized erythrocytes by complement, i.e., 1 a step involving interaction of complement with the sensitized cell, and 2 a subsequent step which appears to be an intrinsic cellular reaction. While the complement reaction step 1 can be blocked by chelating agents such as citrate of ethylene diamine tetraacetate, as well as by competing complement-fixing antigen-antibody systems, the intrinsic reaction step 2 is not arrested by these agents, nor by washing of sensitized cells following treatment with complement, nor by chilling to 0C. The intrinsic process has a low temperature coefficient Q sub 10 about 1.5 and it proceeds at an appreciable rate even at 0C. Measurements conducted at 37C indicate that the intrinsic cellular reaction requires about 2-3 minutes per cell. This time interval, however, does not account adequately for the lag period, and it appears likely that the complement reaction proper step 1 involves a series of 2 or more reaction steps. Evidence obtained in studies on the role of Ca and Mg in immune hemolysis supports this conclusion. Author