Effect of Cyclophosphamide on Lymphoid Tissues of Guinea Pig

Cyclophosphamide (Cy) was administered to Hartley strain guinea pigs by the intraperitoneal route. It was examined for effects on RRBC- and EAC-rosette formation of lymphocytes and on migration and incorporation of 14C-glucosamine of macrophages of the guinea pig. The effects of Cy on the responsiveness of lymphocytes to mitogens and on the development of delayed-type hypersensitivity were also studied. 1. RRBC-rosette forming cells in the thymus decreased remarkably in number after the injection of Cy. 2. When 5 or 10mM/ml Cy was added in vitro to peritoneal macrophages of guinea pig treated in vivo with Cy, the migration and incorporation of 14C-glucosamine of macrophages were inhibited remarkably. 3. Thymic, splenic, and lymph-node cells showed a decrease in response to PHA and ConA after the administration of Cy. All of them, except thymic cells, showed also a decrease in response to LPS. 4. Cy was examined for effect on PPD-induced proliferation of lymphoid cells from guinea pigs immunized with BCG by the aid of 3H-TdR incorporation. The proliferation was inhibited obviously by administration of Cy 24hr prior to, or 24hr after, the sensitization with BCG. No inhibition was observed when Cy was given to animals 8hr prior to, or 8hr after, the sensitization with BCG.