title: T8 cell regulation of human B cell responsiveness: regulatory influences of CD45RA+ and CD45RA- T8 cell subsets.
abstract: The immunoregulatory functions of human T8 cell subpopulations defined by mAb to the CD45RA molecule (2H4) were examined. Both CD45RA+ and CD45RA- T8 cells that had been treated with mitomycin C provided help for the production of immunoglobulins by B cells in cultures stimulated with immobilized mAb to CD3 (64.1). In contrast, both CD45RA+ and CD45RA- T8 cells that had not been treated with mitomycin C suppressed B cell responses in anti-CD3-stimulated cultures, although CD45RA+ T8 cells were more effective in this regard. Interleukin 2 (IL2) enhanced suppression by anti-CD3-activated CD45RA- T8 cells, whereas suppression by CD45RA+ T8 cells was almost maximal and not as much increased by IL2. The differentiation into suppressor-effector cells in this system appeared to involve the production of IL2, but not the production of interferon (INF)-gamma. Thus, CD45RA+ T8 cells produced higher amounts of IL2 but lower amounts of IFN-gamma than CD45RA- T8 cells in anti-CD3-stimulated cultures. Moreover, addition of mAb to the p55 component of IL2 receptor (anti-Tac) inhibited the generation of suppressor activity from CD45RA+ and CD45RA- T8 cells. The pattern and magnitude of suppression of B cell responses by CD45RA+ and CD45RA- T4 cells were similar to that by CD45RA+ and CD45RA- T8 cells in this system. Finally, preactivated CD45RA+ T8 cells that had lost CD45RA expression suppressed the B cell responses as effectively as fresh CD45RA+ T8 cells. The results indicate that both CD45RA+ and CD45RA- T8 cells can help or suppress B cell responses. More importantly, the data suggest that the suppressor-effector function of human T cells may rather be related with the stages of the post-thymic differentiation as evidenced by the expression of the CD45RA molecule than represent the fully differentiated T cell subsets, such as T4 and T8 cells. In addition, the CD45RA molecule appeared not to be involved in the suppressor-effector function, but to determine the stage of post-thymic differentiation.
authors.affiliation: Department of Medicine and Physical Therapy, University of Tokyo School of Medicine, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Hirohata
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D000943:Antigens, Differentiation / Q000276:immunology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D017252:CD3 Complex; D016827:CD8 Antigens; D006649:Histocompatibility Antigens / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000096:biosynthesis / Q000494:pharmacology; D017493:Leukocyte Common Antigens; D008213:Lymphocyte Activation; D009000:Monocytes / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D015375:Receptors, Interleukin-2 / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D016827:CD8 Antigens; D006649:Histocompatibility Antigens; D011948:Receptors, Antigen, T-Cell; D015375:Receptors, Interleukin-2; D007371:Interferon-gamma; D017493:Leukocyte Common Antigens