Platelet-aggregating activity of released factor(s) from Trypanosoma brucei brucei

Abstract

The effect of factors derived from Trypanosoma brucei brucei on rat platelets was studied. T. brucei at a concentration of 4 x 109 trypanosomes/ml phosphate saline glucose (PSG) was stored at -20°C for 18 h. thawed, and a supernatant fraction, trypanosome derived supernatant (TDS) was obtained by spinning the sample at 3000 g for 10 min at 20°C. Normal rat platelets, prepared as platelet-rich plasma (PRP), were then incubated with TDS in the absence or presence of ADP (0.05-0.1 µM). The results showed that approximately 83% platelet aggregation was induced by addition of TDS (50 µl; 113 µg protein) to 100 µl PRP with a platelet count of 106. Simultaneous addition of ADP and TDS to PRP produced a synergistic effect. It was also shown that a supernatant fraction, obtained by incubating live T. brucei (4 x 109/µl PSG) at 0°C for 1 h and spinning down the trypanosomes (3000g for 10 min), also induced platelet aggregation. The nature of the factor(s) derived from, or released by, T. brucei inducing platelet aggregation is being investigated but it has been shown not to be ADP.