An immunological study of tricalcium phosphate supplied by three different manufacturers.

Antigenicity of tricalcium phosphate (TCP) ceramics which were supplied by two Japanese manufacturers and a manufacturer of United States was studied by means of delayed skin reactions in guinea pigs. Skin reactions were elicited 13 days after being immunized by intradermal injection of the ceramics into the dorsal flanks of guinea pigs. After 24 and 48 hr, these reactions were assessed by measuring the diameter of the erythema, the degree of hemorrhaging and its induration. Antigenicity was not detected in the TCP obtained from the Asahi Optical Co., Ltd. and the Kyocera Corporation by means of skin reactions. In contrast, TCP from Miter, Inc. (Synthograft) raised a delayed type hypersensitivity (DTH) 24 hr after antigen elicitation. The reaction appeared to be based on tuberculin type and Jones-Mote type of reactions. Arthus reactions were not observed in either the normal groups or groups immunized with TCP.