Adoptive transfer of suppression of the autoimmune response to rat male accessory glands: characterization of the suppressor cells.

We have examined the mechanism of suppression of autoimmunity to rat male accessory glands (RAG) by T suppressor cells. This suppression was accomplished by transfer to syngeneic rats of spleen mononuclear (SpM) cells from rats rendered unresponsive by pretreatment with low doses of a purified fraction of RAG (containing the autoantigen). The experiments demonstrated that the suppressor cells that act on the inducer phase of the suppression are cyclophosphamide (Cy) sensitive and that they can be positively selected on antigen-coated plates. On the other hand, the inducer phase T suppressor cells present on spleens coming from antigen-pretreated rats did not suppress the autoimmune response in normal recipients that had been irradiated (850 rad 137Cs) just prior to receiving the cells or injected with Cy 14 days after transfer. The results indicate that the regulation of immune response to the autoantigen of RAG is complex and that it involves the interaction of many cell types.

Antigen induced inhibition of autoimmune response to rat male accessory glands: role of thymocytes on the efferent phase of the suppression.

In the present study, we report that Cy-sensitive, MRAG-adherent spleen mononuclear (SpM) inductor-phase T suppressor (Ts) cells obtained from rats pretreated with low doses of a purified fraction (FI) of rat male accessory gland antigens (RAG) are mainly OX19+ and W3/25+. Furthermore, thymocytes from rats pretreated with FI of RAG restore the suppression of the autoimmune response to RAG autoantigens in irradiated recipients of SpM inductor-phase Ts cells. In contrast, thymocytes from rats pretreated with rat heart saline extract (unrelated antigen) did not recuperate the suppression of the autoimmune response detected by macrophage migration inhibitory factor (MIF) and delayed-type hypersensitivity. The suppressor thymocytes did not directly exert their inhibitory effect because they were not effective to suppress the autoimmune response to RAG autoantigens when irradiated recipients did not receive SpM inductor-phase Ts cells. The effect of these thymocytes was found in PNA--but not in PNA+ thymic cell population. The perithymic injection of Toxoplasma gondii did block their suppressor activity. The present report clearly shows an active participation of thymus in the efferent phase of the suppressor circuit that controls the autoimmune response to MRAG. The implications of these findings are discussed.

Effect of gangliosides in the autoimmune response induced by liposome-associated antigens.

A model of autoimmunity to rat male accessory glands (RAG) was recently developed by intraperitoneal administration of three doses of native RAG associated with liposomes. In this work we analysed the effects of gangliosides in the cellular response to RAG when they were intraperitoneally administrated prior to the second dose of liposome-associated RAG. Results show that the ganglioside treatment could modify an established DTH response. Also, gangliosides markedly reduced the number of Ia antigen-positive peritoneal exudated cells (PEC). However, they modified neither the processing of liposomes through PEC nor their viability. Moreover, we obtained cellular response by transferring PEC from immunized donors into naive receptors.

Specific neonatally-induced tolerance to rat male accessory glands antigens. Transference of specific suppression by spleen mononuclear cells.

The immune response of infant rats was studied following (1) immunization of their mothers with modified rat male accessory glands (MRAG) emulsified in complete Freund's adjuvant (CFA), (5 mg/ml or 25 mg/ml) or with human serum albumin (HSA), (5 mg/ml or 25 mg/ml) and (2) intradermal immunization of the offspring at 21 days of age with 5 mg of MRAG-CFA and 5 mg of HSA-CFA. Antibodies to MRAG or to HSA were observed in the sera obtained 20 days after the birth of the offspring. Delayed hypersensitivity (DTH) against MRAG studied 13 days after immunization was significantly reduced in the male offspring born to mothers immunized with 5 mg of MRAG-CFA compared with that of males born to mothers immunized with the same dose of HSA-CFA (P less than 0.0005). In contrast, when 25 mg of MRAG-CFA were used to immunize the mothers, the lack of DTH response to MRAG was observed in male and female offspring (P less than 0.0005 for both groups). In all cases, the DTH response to HSA was positive. The spleen mononuclear (SpM) cells transferred from rats unresponsive to MRAG to normal rats 24 h before the immunization with MRAG-CFA and HSA-CFA did not suppress the immune response whereas transference of SpM cells from suppressed animals to animals previously immunized depressed the DTH response to MRAG (suppression of the expression). The response to HSA was not affected. We can conclude that the suppression is antigen specific.

[Regulation of the autoimmune response against antigens of male accessory glands of rats]. / Estudio de la regulación de la respuesta autoinmune contra antígenos de glándulas sexuales accesorias masculinas de rata.

Rats immunized with chemically modified rat male accessory glands (MRAG) elicit organ and species specific autoimmune response. We have developed suppression of autoimmunity to MRAG injecting syngeneic rats, previous to immunization with MRAG-CFA, with low doses of the same antigen. The unresponsiveness was mediated, by inducer phase, cyclophosphamide (Cy)-sensitive, antigen specific, T suppressor lymphocytes and effector phase, Cy and irradiation sensitive T lymphocytes. Moreover, we demonstrated that macrophages could play a role in the induction of these MRAG-specific suppressor T lymphocytes. On the other hand, we studied the influence of an infection with Toxoplasma gondii on rats immunized with MRAG-CFA. The cellular and humoral immune responses to MRAG were selectively potentiated in animals infected in thymus proximity, whereas the infection did not modify the response to an heteroantigen, human serum albumin (HSA). The i.p. infection did not alter the cellular response. The potentiation of cellular autoimmune response was correlated with thymic involution and proliferation of lymphocytes and plasma cells. A decrease of Ox-8, Ox-18 and Ox-17 surface markers in thymic cellular population and an increase of immature thymocytes (PNA+) were observed in these animals in correlation with the blockage of the effector phase of suppressor cell circuit. In another study we found that the male kits born to mothers immunized with 5 mg of MRAG-CFA showed significantly reduced DTH response to MRAG. When the mothers were immunized with 25 mg of MRAG-CFA the lack of DTH response was observed in male and female kits. In all cases, the DTH response to HSA was positive.(ABSTRACT TRUNCATED AT 250 WORDS)

Maternal-fetal interactions on the regulation of the autoimmune response.

Adult female rats were immunized with 5 mg or 25 mg of modified rat male accessory glands (MRAG) incorporated to complete Freund's adjuvant (CFA) before, during, and after pregnancy. The mothers and litters were exchanged between the experimental and normal groups. The offspring were brought up to 20 days of age and immunized with 5 mg of MRAG-CFA and 5 mg of human serum albumin (HSA)-CFA. Anti-MRAG antibodies were detected in the offspring brought up by the immunized mothers and the titers were similar to those of the foster mothers whereas in the offspring of the experimental group fostered by normal mothers antibodies to MRAG were not detected. The DTH performed in the offspring 13 days after the immunization was significantly diminished in male and female offspring from the 5 mg and 25 mg experimental group fostered by normal mothers (P less than 0.0005 for all groups). Similar results were found when the offspring from normal mothers were suckled by mothers immunized with MRAG-CFA. To assess whether MRAG or HSA administered to female rats reached the offspring via the placenta or the milk, female rats were immunized with 3 mg of 125I-MRAG-CFA or with 3 mg of 125I-HSA-CFA. When radioactivity was measured in neonates (n = 11) that were suckled by the 125I-MRAG-CFA immunized mothers, the specific activity was 116 in stomach (0.4 micrograms of MRAG) and 940 in the total organs (3.8 micrograms of MRAG).(ABSTRACT TRUNCATED AT 250 WORDS)

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

The present report describes different aspects of two populations of peritoneal cells (PC) obtained from rats injected 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). The FI-PC2h, which are mainly I-E (OX17) positive and can suppress the autoimmune response to RAG autoantigens, have an elevated phagocytic activity against Candida albicans and capacity to reduce the dye nitroblue tetrazolium. In contrast, FI-PC24h, which are mainly I-A (OX6) positive and can potentiate the autoimmunity to RAG autoantigens, have a diminished capacity to reduce the dye and a diminished phagocytic activity. Moreover, the Toxoplasma gondii appear to have a different effect on both populations. The parasites can invade FI-PC2h while FI-PC24h offer resistance to T. gondii aggression. FI-PC2h cultured during 22 h (FI-PC2-24h in vitro), or PC obtained from syngeneic recipients injected i.p. 22 h previously with FI-PC2h (FI-PC2-24h in vivo) show, as FI-PC2h, an increase of the I-E+ cells and capacity to induce suppression of the delayed-type hypersensitivity response to RAG autoantigens when they are injected to syngeneic rats 10 and 3 days prior to the immunization with chemically modified (diazotized arsanilic and sulfanilic acid) RAG in complete Freund's adjuvant. The PC obtained 24 h after injection of irradiated rats with N-PC plus FI show an increase of I-E+ cells whereas an enhancement of I-A+ cells can be observed when the PC are obtained 24 h after injection of irradiated and bone marrow-reconstituted rats with N-PC plus FI. These findings appear to indicate that FI-PC2h and FI-PC24h are functionally different and that the population obtained 24 h after injection of FI of RAG could not originate from either the population present 2 h after injection of FI of RAG injection nor from normal PC. They appear to require bone marrow precursors.