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

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.