Human T cell clones specific for tetanus toxoid: characterization of antigen specificity and HLA restriction.

T cell blasts isolated from six-day cultures of peripheral blood mononuclear cells stimulated with tetanus toxoid (TT) were cloned in a two-layer agar system in the presence of autologous irradiated PBM (iPBM) and TT. Colonies were individually isolated and expanded in interleukin 2-containing medium. The antigen specificity of three T cell clones was attested by their capacity to proliferate under restimulation by TT and not by an unrelated antigen. The clones were specific for either the alpha or the beta chain of the toxin. T cells from these clones expressed Ia determinants and antigens of the helper/inducer T cell subset as defined by anti-T monoclonal antibodies. In the case of the alpha chain-specific clone MA 11 from the donor MA, allogeneic iPBM from HLA-compatible unrelated donors, including seven donors sharing one HLA DR specificity with MA, were found inefficient as antigen-presenting cells. A familial study, however, demonstrated that antigen presentation could be obtained using nonautologous cells. The presenting capability of cells from relatives of the donor MA segregated in association with the HLA-DRw6-bearing maternal haplotype present in MA. Results suggest that MA 11 cells recognized the antigen in the context of a surface determinant closely linked to HLA-DRw6.