Human platelet chemotaxis can be induced by low molecular substance(s) derived from the interaction of plasma and...

Previously, we reported that collagen induces chemotaxis of human platelets as revealed by a capillary-tube method for qualitative assessment of platelet migration (Lowenhaupt, 1978). Chemotaxis was presumably stimulated by a substance(s) generated from collagen incubated in plasma. We have now developed a new quantitative method for evaluating chemotaxis by using 111indium-oxine labeled platelets. Blood from healthy donors was drawn into plastic syringes containing acid-citrate-dextrose. Platelet-rich and platelet-free plasma were prepared as described previously. Platelets were labeled with 111In-oxine according to Goodwin et al (1978) Chemotaxis was studied in a specifically constructed 7-compartment chamber partitioned with nitro-cellulose membranes (3 micrometers, 1 micrometer, and 0.45 micrometer). Chemotaxis could be induced with collagen from either bovine or rat-tail tendon. Molecular sieving of normal plasma on Sephadex G-50 showed a peak (A 220 nm) of low molecular weight material which was shifted to the right in preparations preincubated with either bovine tendon or rat-tail tendon collagen. Aliquots from the control plasma peak did not produce chemotaxis. In contrast, aliquots from the collagen-plasma peak markedly stimulated chemotaxis. These findings suggest that plasma releases a low-molecular moiety(s) from collagen which promotes chemotaxis.