title: Cellular origins and target cells of immunoregulatory factors in mice with disseminated histoplasmosis.
abstract: Disseminated infection with Histoplasma capsulatum stimulates the production of a suppressor factor (SF-H) by spleen cells from C3H/HeJ mice and a helper factor (HF-H) by spleen cells from C57BL/6 mice. In the present study these disparate immunoregulatory factors were analyzed in detail with regard to: a) the surface phenotype of the cells that produce SF-H and HF-H; b) the role of accessory cells in the production of these factors; and c) the surface phenotype of the target cells activated by SF-H and HF-H. Treatment of spleen cells from Histoplasma-infected C3H/HeJ mice with anti-Thy-1.2 plus complement (C) or with anti-Ly-2 plus C or with anti-I-Jk antiserum plus C abolished production of SF-H. Conversely, generation of HF-H by spleen cells from C57BL/6 mice was abrogated by treatment with either anti-Thy-1.2 plus C or with anti-Ly-1 plus C. Thus, a Thy-1.2+, Ly-2+, I-J+ T cell releases SF-H, and a Thy-1.2+, Ly-1+ T cell secretes HF-H. Production of SF-H and HF-H by splenic T cells was reduced markedly by depletion of macrophages (M phi); readdition of 1% syngeneic, plastic-adherent splenocytes from normal or infected mice to M phi-depleted, splenic T cell cultures of either strain restored the capacity to generate immunoregulatory factors. Furthermore, adherent splenocytes from normal or infected mice liberated a factor or factors that enhanced production of both SF-H and HF-H. Kinetic studies demonstrated that activation of normal spleen cells required at least 48 hr of exposure to SF-H or HF-H. Both factors failed to activate splenocytes pretreated with anti-Thy-1.2 plus C. Spleen cells from C3H/HeJ mice depleted of Ly-1+, Ly-2+, or I-J+ cells and exposed to SF-H did not demonstrate suppressor activity, whereas Ly-1-depleted splenocytes from C57BL/6 mice exposed to HF-H failed to exert helper activity. Therefore, the target of SF-H is a Thy-1.2+, Ly-1+2+, I-J+ T cell, and the target of HF-H is a Thy-1.2+, Ly-1+ T cell.
mesh_terms: D000818:Animals; D000921:Antibody-Producing Cells / Q000276:immunology*; D006660:Histoplasmosis / Q000276:immunology*; D007376:Interleukin-2 / Q000096:biosynthesis* / Q000502:physiology; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D008222:Lymphokines / Q000096:biosynthesis* / Q000502:physiology; D008264:Macrophages / Q000276:immunology; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D013154:Spleen / Q000166:cytology; D013491:Suppressor Factors, Immunologic; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D007376:Interleukin-2; D008222:Lymphokines; D013491:Suppressor Factors, Immunologic