Reticulo-endothelial system activity during homograft rejection and immunosuppression

Abstract

Abstract Reticulo-endothelial system activity was measured in the rat by the rate of colloid clearance. Activity was increased following homograft rejection, and in the presence of tumour-specific antigen. Increased activity was also found during immunosuppression with cyclophosphamide, and with methotrexate, despite marked lowering of the white blood-counts. It is concluded that reticulo-endothelial system activity does not parallel the activity of the lymphoid system in transplantation immunity.