Differential sensitivity to cyclophosphamide of helper T cells for humoral responses and suppressor T cells for delayed‐type hypersensitivity

摘要

AbstractThe relative sensitivity to cyclophosphamide (CY) of helper T cells in antibody responses and of suppressor T cells in delayed‐type hypersensitivity (DTH) responses against sheep red blood cells (SRBC) was measured by pretreating cell suspensionsin vitrowith the microsomally activated form of CY and evaluating their subsequent function in transfer experiments. It was found that suppressor T cells involved in DTH responses were sensitive to much lower concentrations of activated CY than were helper T cells for anti‐SRBC antibody responses. Since the cytotoxic activity of CY is thought to be dependent on its ability to alkylate nuclear DNA, the differential sensitivity observed may be more easily explicable in terms of additional secondary enzyme‐mediated degradation or DNA repair mecha