A monoclonal antibody (145-2C11) specific for the murine T3 complex was derived by immunizing Armenian hamsters with a murine cytolytic T-cell clone. The antibody is specific for a 25-kDa protein component (T3-epsilon) of the antigen-specific T-cell receptor. It reacts with all mature T cells and can both activate and inhibit T-cell function. These results identify T3-epsilon as a cell surface protein involved in the transduction of activation signals.

https://www.pnas.org/content/pnas/84/5/1374.full.pdf

Identification of a monoclonal antibody specific for a murine T3 polypeptide

TIL from metastatic melanoma proliferated by greater than 1,000-fold (840-3,675, mean 1,543) after 6 wk in culture of mixtures of TIL and tumor cells with rIL-2 alone. Cytolysis was restricted to autologous tumor cells. CD8+ T cells were the predominant population of TIL before and after expansion, and were primarily responsible for autologous tumor-specific CTL activity. No other rIL-2-activated lymphocytes from peripheral blood, lymph nodes with melanoma metastasis, or TIL from sarcoma or renal cell carcinoma had autologous tumor-specific CTL activity. There were few or no CD16+ NK cells in TIL from metastatic melanoma before or after incubation with rIL-2, respectively. However, TIL from sarcoma or renal cell carcinoma contained a substantial proportion of CD3-CD16+ NK cells, which increased in number in culture with rIL-2. Purified CD16+ NK cells as well as CD3+CD16- T cells from rIL-2-activated TIL of renal cell carcinoma displayed MHC-nonrestricted cytotoxicity. At the clonal level as determined by limiting dilution, 8 of 10 clones from melanoma TIL displayed cytotoxicity restricted to autologous tumor cells, while all 13 clones from renal cancer TIL equally lysed autologous and allogeneic tumor cells. Anti-T cell receptor (TCR)-alpha/beta(WT31) mAb as well as anti-CD3 mAb inhibited autologous melanoma cell-specific CTL activity mediated by rIL-2-activated TIL at the effector phase. These two mAbs also inhibited rIL-2-dependent proliferation of these TIL when added to the culture. Pretreatment of fresh melanoma cells with mAb to MHC antigens followed by washing inhibited specific CTL activity. These results suggest that both TCR-alpha/beta on effector TIL and MHC antigens on fresh tumor cells are involved in the specific immune-recognition. After reaching maximum propagation, TIL from metastatic melanoma responded poorly to rIL-2 alone. However, stimulation with fresh autologous melanoma cells restored both CTL activity and proliferation in response to rIL-2. The latter is associated with IL-2 receptor (Tac antigen) expression on the surface. These results indicate that TIL from metastatic melanomas may have unique characteristics different from lymphocytes obtained from the other sources, and may contain precursor CTL sensitized in vivo to autologous tumor cells, and thus can be propagated in larger numbers with rIL-2 alone while retaining autologous tumor-specific CTL activity.

https://rupress.org/jem/article-pdf/168/4/1419/1098536/1419.pdf

Autologous tumor-specific cytotoxic T lymphocytes in the infiltrate of human metastatic melanomas. Activation by interleukin 2 and autologous tumor cells, and involvement of the T cell receptor.

Previous studies have shown that heteroconjugates of monoclonal antibodies in which one of the component antibodies is directed at the T-cell receptor and the other is directed against any chosen site can focus effector T cells to function at the targeted site. We report here the production of a hybrid hybridoma cell line, H1.10.1.6, which secretes large amounts of a bispecific hybrid antibody of the IgG2a class, that can focus T-cell activity. The parental hybridoma lines for the secondary fusion were F23.1, which secretes an antibody specific for an allotypic determinant on the T-cell receptor of most mouse strains, and 19E12, secreting an anti-Thy-1.1 antibody. The bispecific hybrid antibody was partially purified by hydroxylapatite chromatography and characterized by isoelectric focusing. It efficiently targets Thy-1.1-expressing tumor cells for lysis by F23.1 receptor-positive cytotoxic T-cell clones in vitro. Such hybrid antibodies produced by hybrid hybridoma cell lines may have application in the therapeutic targeting of tumors or sites of viral infections for attack by T cells.

https://www.pnas.org/content/pnas/83/5/1453.full.pdf

Hybrid hybridoma producing a bispecific monoclonal antibody that can focus effector T-cell activity

LFA-1 and other accessory molecules functioning in adhesions of T and B lymphocytes.

Publisher Summary To deal with intracellular organisms, the immune system has evolved a quite different set of immunocompetent cells, T cells. These cells are imbued with a number of interesting properties. In contrast to B cells and antibody molecules, T cells generally do not manifest specificity. Unlike B cells, T cells do not secrete their antigen-specific receptors. Under physiological conditions, T cells only respond to antigen displayed on the surface of living cells. T cells show the intriguing requirement that, to be immunogenic, antigen has to be aligned on the cell surface in association with gene products of the major histocompatibility complex (MHC), the H-2 complex, in mice. Parasitized cells recognized by T cells, especially in the case of viral infections, are destroyed by cytotoxic T lymphocytes (CTL), a subset of T cells with cytolytic properties. T cells also play a major role in controlling the quantity and quality of specific antibody made by B cells. This function of T cells is controlled by a different subset of T cells, T helper cells. Whereas T killer cells provide a negative (cytotoxic) signal to antigen-bearing cells, T helper cells provide a positive signal. The chapter outlines the way the specificity, function, and induction of T cells and T cell subsets are under the strict control of H-2 molecules.

Function and specificity of T cell subsets in the mouse.

Lysis of anti-T3-bearing murine hybridoma cells by human allospecific cytotoxic T cell clones and inhibition of that lysis by anti-T3 and anti-LFA-1 antibodies.

R W Hoffman

Papers

Lysis of anti-T3-bearing murine hybridoma cells by human allospecific cytotoxic T cell clones and inhibition of that lysis by anti-T3 and anti-LFA-1 antibodies.