Antigen-induced inhibition of autoimmune response to rat male accessory glands: distinct role of I-A and I-E-positive peritoneal cells.

The present report describes the structural and functional characteristics of the population of peritoneal cells (PC) from rats injected intraperitoneally (i.p.) 2 h or 24 h previously with a suppressor dose of a purified fraction (FI) of rat male accessory glands (RAG: FI-PC2h and FI-PC24h, respectively). Both populations of PC showed the presence of the autoantigens of RAG on their membrane. The study of cell surface marker showed increase of OX17 (I-E) in FI-PC2h and OX6 (I-A) in FI-PC24h. I.p. injection of FI-PC2h 10 and 3 days prior to immunization with chemically modified (diazotized arsanilic and sulfanilic acid) RAG (MRAG) in complete Freund's adjuvant induced suppression of the delayed-type hypersensitivity (DTH) response to MRAG, whereas the i.p. injection of FI-PC24h induced potentiation of DTH response to MRAG when compared with controls (animals injected 10 and 3 days prior to immunization with PC from rats injected i.p. with an unrelated antigen). The treatment of FI-PC2h with OX17 and FI-PC24h with OX6 prior to the transfer blocked the suppression and potentiation described above. These findings show that the i.p. injection of an FI of RAG at a suppressor dose induces PC with immunologically opposite characteristics, depending on the time of obtention.