CELLS INVOLVED IN THE REGULATION OF THE AUTOIMMUNE-RESPONSE TO RAT MALE ACCESSORY-GLANDS

1. The immunization of Wistar rats with 5 mg of chemically modified ra t male accessory glands saline extract (MRAG) incorporated into comple te Freund's adjuvant (CFA) induced a delayed type hypersensitivity (DT H) response to rat male accessory glands (RAG). Pretreatment with peri toneal cells (PC) obtained from rats 2 h after an intraperitoneal tip) injection of a partially purified fraction (FI) of RAG (FI-PC2h) supp ressed the DTH response to MRAG after immunization with MRAG-CFA, whil e pretreatment with PC obtained 24 h after an ip injection of FI-RAG ( FI-PC24h) induced potentiation of the DTH response to MRAG. 2. The inj ection of spleen mononuclear cells (SpM), obtained from rats rendered unresponsive to MRAG by pretreatment with FI-PC2h, into normal syngene ic recipients markedly prevented the DTH reaction to MRAG. The transfe r of SpM cells from animals injected with FI-PC24h (potentiated animal s) to suppressed recipients (recipients of FI-PC2h on days -10 and -3, prior to immunization with MRAG-CFA) showed that SpM cells did not el iminate the suppression state in these recipients, but when they were transferred to normal recipients, they were able to induce a positive response to RAG (P<0.005). 3. The study of the phenotypic characterist ics of the SpM cells prior to transfer showed similar numbers of CD4 a nd IL-2R SpM cells in both potentiated and normal animals. However, th e number of CD8 cells was significantly reduced in SpM cells from pote ntiated animals compared to that observed in SpM cells from normal ani mals (P<0.05).