EFFECTS OF RETINOIDS ON REGULATORY CELLULAR INTERACTIONS IN PRIMARY MIXED LYMPHOCYTE-REACTION (MLR)

The effects of two retinoids, all-trans-retinoic acid and 13-cis-retin oic acid on murine splenic lymphocyte proliferative response in mixed culture were evaluated. In contrast with previously reported absence o f retinoic acid (RA) effect on mixed lymphocyte reaction (MLR) the con ditions for a strong potentiation of proliferative response of murine lymphocyes with RA were obtained. Stimulatory cells were determined to be the main targets for RA. The data suggest that the RA potentiating effect is the result of an increase in stimulator cell immunogenicity after their pre-treatment with RA before use in MLR. Optimal potentia tion by retinoids of proliferative response was found at non-optimal c onditions of mixed culture.