Inhibitors of haemaggregation in biological fluids.

Haemaggregation has been observed in phosphate and barbiturate buffers and in the presence of sodium chloride as well as in the borax-succinic acid buffer previously described; in all these buffers haemaggregation-inhibition by tuberculin was also observed. The most satisfactory technique used cells aggregated with protamine in phosphate buffer. By electrophoresis it was shown that serum contained several haemaggregation-inhibiting components; some were distinct from inhibitors of virus haemagglutination. The inhibitor in urine remained in solution after Tamm-Horsfall protein was precipitated and concentrated supernatants inhibited virus multiplication; biological activity was lost after further purification, but immunodiffusion of purified material revealed an unidentified precipitinogen. Highly purified blood group glycoprotein inhibited haemaggregation to very high titre but did not inhibit virus growth.