Inhibition of Human Tumor Cell Induced Platelet Aggregation by Antibodies to Platelet Glycoproteins lb and llb/llla

Abstract

Abstract

Tumor cell induced platelet aggregation was shown to be inhibited in a dose dependent manner by preincubation of human platelets with antibodies to platelet glycoprtein lb and the llb/llla complex. Combination of antibody to lb and antibody to the llb/llla complex at concentrations which produced half maximal inhibition of platelet aggregation alone caused complete inhibition of tumor cell induced platelet aggregation. Antibodies to platelet glycoproteins lb and the llb/llla complex also inhibited platelet synthesis of thromboxane A2, but not synthesis of 12-hydroxyeicosatrienoic acid. Inhibition of tumor cell induced platelet aggregation with antibodies against platelet glycoproteins suggests a role for these glycoproteins in tumor cell-platelet interactions and possibly platelet facilitated tumor cell metastasis.