Functional analysis of two human T-cell subpopulations: help and suppression of B-cell responses by T cells bearing receptors for IgM or IgG.

Abstract

Subpopulations of thymus-derived T lymphocytes bearing receptors for either IgM or IgG molecules were isolated from human peripheral blood. Those with receptors for IgM (T.M) provided help in a cell dose-dependent fashion for the pokeweed mitogen-induced differentiation of B lymphocytes in vitro, whereas cells with receptors for IgG (T.G) did not. T.G cells, on the hand, efficiently suppressed the differentiation and proliferation of B cells in the pokeweed system in the presence of helper T.M cells. This suppressive activity of T.G cells required prior interaction of the T.G cells with immune complexes. The helper activity of T.M cells was relatively radioresistant while the suppressor activity of T.G cells was radiosensitive. The results indicate that helper and suppressor functions of human T lymphocytes in this model system are mediated by different subpopulations of T cells which can be distinguished by their ability to bind IgM or IgG immune complexes, respectively.

Induced Expression of FcγRIIIa (CD16a) on CD4+ T Cells Triggers Generation of IFN-γhigh Subset

“…ϩ T-cells express low affinity ϩ T-cells, their role in T-cell mediated immune responses has been largely ignored (15,17,41,42). We observed a co-staining of ICs with the CD3 complex on CD4…”

Immunoregulatory T cell function in patients with primary biliary cirrhosis.

“…Anti-lymphocyte antibodies that appear to have a specificity against suppressor T cells have been found in sera from patients with juvenile rheumatoid arthritis (Strelkauskas et al 1978), systemic lupus erythematosus (Sagawa and Abdou 1979) and, though preliminary, in PBC (Miller et al 1980). Some suppressor T cells are thought to have IgG/Fc-receptors (Moretta et al 1976(Moretta et al , 1977, which may be blocked by circulating immune complexes. This may result in an alteration of suppressor T cell function in PBC patients having a large amount of immune complexes in their sera.…”

Immunoregulation in Sjögren's Syndrome

“…This is of particular relevance in light of the fact that in several in vitro systems, SLE has been demonstrated to manifest a deficiency of suppressor cell function (23,(30)(31)(32)(33)(34)(35). Although the actual suppressor cell in most of these systems has not been conclusively identified, at least in some systems of in vitro B-cell function, the TG cell has been demonstrated to be the suppressor cell (16). With regard to the relationship between deficiency ofTG cells and lack of suppressor cell function, it should be pointed out that patients with SLE in addition to the deficiency of TG cells (23,24) also manifest a defective ability to generate, after triggering with Con A, suppressor cells of PWMinduced PFC responses (23).…”

“…T-cell subpopulations were determined as previously described in detail (15,16). Briefly, to identify T cells bearing receptors for the Fc portion of IgG (TG), 0.1 ml of purified T cells at a concentration of 10 X 106 cells/ml was mixed with 0.1 ml of a 2% suspension of bovine E coated with highly purified rabbit antibovine E IgG antibody (7S EA).…”