STUDIES ON LYSOSOMES V. The Effects of Streptolysins and Other Hemolytic Agents on Isolated Leucocyte Granules

Granules from rabbit peritoneal leucocytes were prepared in 0.3 ~ sucrose as an optically homogeneous suspension with the aid of heparin. Lysis of the granules in vitro was followed by measurement of decreases in the apparent absorbance of the suspensions at 520 m# and was accompanied by solubilization of beta-glucuronidase from the particles. Streptolysins O and S from hemolytic streptococci lysed the granules at 20°C; the initial rate of lysis by streptolysin O was greater than that by streptolysin S. Cysteine activated, and specific antibody inhibited, streptolysin O; antimycin and bovine serum albumin inhibited streptolysin S. The granules were not lysed by any other streptococcal exotoxins. Lysis was irreversible and depended neither upon oxidative phosphorylation, nor upon intact respiration. The granules were also lysed by lysolecithin, at concentrations from 2 × 10 -6 M to 1 × 10 -4 M; bovine serum albumin and antimycin also inhibited this lytic agent. Such other hemolytic agents and procedures as vitamin A, non-ionic detergents, and ultraviolet irradiation also disrupted leucocyte granules. In susceptibility to lysis and other properties, the granules of white cells resembled erythrocytes. Leucocyte granules differed from mitochondria in that they did not appear to take up or extrude water reversibly; they were unaffected by thyroxine, phosphate, or metabolic substrate. The studies are compatible with the hypotheses that white cell granules are similar to lysosomes isolated from other tissues, and that they share common surface properties with erythrocytes. Streptolysins O and S from hemolytic streptococci injure not only the membranes of red cells, but disrupt hepatic lysosomes (1) and cause the swelling of mitochondria with solubilization of mitoehondrial enzymes (2). They are also lethal for intact leucocytes, the death of which has been attributed to an action of the lysins on the specific granules of white cells (3). Leucocyte granules, when isolated, have been shown to possess many of the properties of lysosomes from other tissues: a number of hydrolases with an optimal pH in the acid range such as cathepsins, DNase, RNase, acid phosphatase, and beta-glucuronidase, etc. can be released from the granules by such methods as freezing and thawing, incubation at acid pH, or exposure to detergents (4). Studies of the actions of streptolysins on lysosomes have left several unresolved problems (1). Whereas streptolysin S was at least ten times more active than streptolysin O in causing the release of enzymes from mitochondria and lysosomes (1, 2), it was less active than streptolysin O in causing damage to the specific granules of intact leucocytes and acted on these only after a considerable lag period (3). Lysis of leucocyte granules followed shortly after the addition of strepto115 on A ril 9, 2017 D ow nladed fom Published July 1, 1964