title: Role of accessory cells in the activation of pure T cells via the T cell receptor-CD3 complex or with phytohaemagglutinin.
abstract: The ability of different subpopulations of blood mononuclear cells to serve as accessory cells in the activation of CD4+ and CD8+ T cells via Ti-CD3 or with phytohaemagglutinin (PHA) was studied. Pure CD4+ or CD8+ T cells did not respond to particle-bound anti-CD3 monoclonal antibodies (MoAb) or PHA, whereas responses were seen when non-T cells served as accessory cells. Removal of class II-positive cells from peripheral blood mononuclear cells (PBMC) or from non-T cells diminished, but did not completely abolish, the responses in both T cell subsets, indicating that the accessory cells are mainly found among the class II-positive cells. However, the class II molecules themselves were not involved, as demonstrated in antibody-blocking experiments. Removal of monocytes decreased the ability of non-T cells to serve as accessory cells for both CD4+ and CD8+ cells in PHA activation. In contrast, the removal of monocytes resulted in an enhanced activation by anti-CD3 MoAb in CD4+ T cells, while the activation of CD8+ T cells was less affected. Positively selected B cells were effective accessory cells in anti-CD3 and PHA activation. Furthermore, Epstein-Barr virus (EBV)-transformed B cell lines were very potent accessory cells both in anti-CD3 and PHA activation of T cells, and showed the strongest accessory cell function observed in this system on a per cell basis.
authors.affiliation: Institute of Transplantation Immunology, National Hospital, Rikshospitalet, Oslo, Norway.
authors.forename: R
authors.initials: R
authors.lastname: Halvorsen
authors.forename: T
authors.initials: T
authors.lastname: Leivestad
authors.forename: G
authors.initials: G
authors.lastname: Gaudernack
authors.forename: E
authors.initials: E
authors.lastname: Thorsby
mesh_terms: D000938:Antigen-Presenting Cells / Q000276:immunology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D017252:CD3 Complex; D006801:Humans; D066298:In Vitro Techniques; D008213:Lymphocyte Activation; D010835:Phytohemagglutinins / Q000494:pharmacology; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D010835:Phytohemagglutinins; D011948:Receptors, Antigen, T-Cell