Nature of the Anticlotting Activity of Streptococci in vitro.

Abstract

While studying factors affecting the formation of the fibrinous inflammatory barrier in acute local streptococcal inflammation, Dennis and Berberian 1 confirmed the observations of Tillett and Garner 2 on streptococcal fibrinolysin, and described the presence of an anticoagulant in filtrates of certain strains of hemolytic streptococci and of virulent viridans streptococci. Although certain strains of erysipelas streptococci produced both fibrinolytic and anticoagulant factors, sound evidence was offered that we were dealing with 2 distinctly different substances. The differences were: fibrinolysin was never produced by Strep. viridans; fibrinolysin acted only upon human plasma clot, while the anticoagulant prevented the clotting of both human and rabbit recalcified oxalated plasma; and fibrinolysin was thermolabile while the anticoagulant was thermostable. Anticlotting factor masked the action of fibrinolysin whenever the two occurred together. Tunnicliff 3 confirmed our observations and correlated the anticlotting activity with the smooth (S) phase of greening streptococci. Neter and Witebsky, 4 apparently unaware of our earlier observations, recently reported on the anticoagulant activity of streptococcal filtrates, but failed to recognize the fundamental difference between anticoagulant and fibrinolytic phenomena.

During the past 3 years we have extended our observations on the nature of the anticlotting activity, using 45 strains of Strep. hemolyticus and 18 strains of Strep. viridans. We have used the original method of Tillett and Garner 2 throughout for the demonstration of fibrinolytic and anticlotting action.

Using filtrate of an E₁ strain of S. hemolyticus which was both fibrinolytic and anticoagulant, and various S. viridans filtrates which were anticoagulant only, an effort was made to isolate and identify the anticlotting factor. It was found that the anticoagulant is soluble in 75% alcohol, absolute alcohol, and ether. It is readily dialyzable when in a relatively pure state, and gives a strongly positive Kelling's test for lactic acid.