The effect of two soluble thalidomide derivatives on lymphocyte stimulation

Abstract

The soluble thalidomide derivatives, 1-(morpholinomethyl)-4-phthalimido-piperidindione-2,6 (CG603) and its isomer 1-(morpholinomethyl)-3-phthalimido-piperidindione-2,6 (CG601) have been found to inhibit the production of transformed cells in 90-hr mixed lymphocyte cultures from two unrelated human donors. In 72-hr phytohaemagglutinin cultures however, the incorporation of thymidine into the acid insoluble fraction was not inhibited by the same concentration of drugs. Since the initial event in the mixed lymphocyte reaction is considered to be immunological whereas the response to phytohaemagglutinin is not, one possible explanation is that the compounds act by blocking a step in the lymphocyte stimulation pathway between the reception of the antigen, and the site where the phytohaemagglutinin bypass is effective.