Characterization of efferent T suppressor cells induced by Paracoccidioides brasiliensis-specific afferent T suppressor cells.
Previously, we reported that Paracoccidioides brasiliensis culture filtrate antigen (Pb.Ag) when injected i.v. into mice induces antigen-specific suppressor cells which down-regulate the anti-P. brasiliensis delayed-type hypersensitivity (DTH) response. The suppressor cells are present in both spleens and lymph nodes of Pb.Ag-treated animals and suppress the afferent limb but not the efferent limb of the DTH response to P. brasiliensis. The suppressor cells induced by Pb.Ag are L3T4+ Lyt-1+2- I-J+ T cells and are considered to be equivalent to the Ts1 cells described for other antigen-specific suppressor cell pathways. This report provides data which show that Ts1 cells induced by Pb.Ag or a soluble factor derived from Ts1 cells (TsF1) stimulates the production of second-order or efferent suppressor cells. The second-order suppressor cells are detectable in spleens and lymph nodes of mice 7 days after injection of Ts1 cells or TsF1 and are specific in suppressing the paracoccidioidal DTH response. In addition, the second-order suppressor cells are T cells with an L3T4- Lyt-2+ I-J+ phenotype and are effective in suppressing only the efferent limb of the P. brasiliensis DTH response. On the basis of the characteristics defined in this study, the paracoccidioidal second-order suppressor cells are equivalent to the Ts2 cells described for other antigen-specific suppressor-cell pathways. Thus, the suppressive circuit induced by Pb.Ag is similar to the suppressor-cell pathways that regulate the DTH responses to azobenzenearsonate, 4-hydroxy-3-nitrophenyl acetyl, lysozyme, and Cryptococcus neoformans antigen. We propose that such a suppressor-cell circuit as defined here with the murine model could be responsible for the depressed cell-mediated immune responses observed in paracoccidioidomycosis patients who have antigen circulating in their sera.
Jimenez-Finkel
B E
BE
Department of Botany/Microbiology, University of Oklahoma, Norman 73019.
Murphy
J W
JW
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis*; D000946:Antigens, Fungal / Q000276:immunology*; D006968:Hypersensitivity, Delayed / Q000276:immunology; D007108:Immune Tolerance; D007111:Immunity, Cellular; D008198:Lymph Nodes / Q000276:immunology; D051379:Mice; D003904:Mitosporic Fungi / Q000276:immunology*; D010228:Paracoccidioides / Q000276:immunology*; D010229:Paracoccidioidomycosis / Q000276:immunology*; D013154:Spleen / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000145:classification / Q000276:immunology*; D013997:Time Factors
D000945:Antigens, Differentiation, T-Lymphocyte; D000946:Antigens, Fungal