Different suppressive effects of combined cyclophosphamide-antigen treatment compared with exclusive cyclophosphamide treatment on primary and secondary humoral immune reactivity.
The immunosuppressive effect of a combined treatment with antigen (C3H erythrocytes - ME) and cyclophosphamide (CY - dosage 65% LD50) has been studied in inbred CAP rats showing different degrees of immunological reactivity. When primary reactivity existed before treatment, this reactivity was not abolished but diminished. When weak secondary reactivity (after one antigen injection) existed before treatment this reactivity was abolished and again diminished primary reactivity was found. When strong secondary reactivity (after 4 antigen injections) existed before treatment selective unresponsiveness was found during the 4 weeks following treatment. 12 weeks after treatment  diminished primary reactivity was found again. When the same dose of CY was given without antigen no immunosuppressive effect could be seen - irrespective of whether primary, weak or strong secondary reactivity existed. The results indicate that in this model it is easier to induce selective unresponsiveness in sensitized than in nonsensitized rats and suggest that primed lymphocytes are more susceptible to a combined antigen-CY treatment than unprimed cells.
D000818:Animals; D000917:Antibody Formation / Q000187:drug effects*; D000941:Antigens / Q000008:administration & dosage; D003520:Cyclophosphamide / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D007156:Immunologic Memory / Q000187:drug effects*; D007165:Immunosuppression Therapy; D051381:Rats; D013997:Time Factors
D000941:Antigens; D003520:Cyclophosphamide