BLOOD PLATELETS AND TRANSPLANTATION ANTIGENS*

Abstract

Studies were conducted with rats and guinea pigs to determine whether their platelets share transplantation antigens in common with skin. Relatively high dosage inocula of blood platelets (equivalent in cytoplasm to that present in 4-60 X 107 spleen cells) from B.N. [rat strain] donors inoculated into adult Lewis rats failed to excite more than marginal sensitivities to subsequent skin homografts having the same genetic origin as the platelets. These sensitivities are most probably provoked by con -taminating leucocytes. Serum from B.N. rats inoculated with homologous platelet concentrates provoked immediate PCA-type cutaneous reactions when administered intradermally to Lewis recipients. The i.d. injection of homologous platelet concentrates into guinea pigs specifically presensitized by homotransplantation of skin provoked the formation of delayed type hypersensitivity reactions attributable to the presence of isoantigens in platelets. In the light of the findings of other workers, it seems reasonable to conclude that platelets do share at least some transplantation antigens in common with skin in this species.