Induction of antigen-specific suppressor cells in patients with hay fever receiving immunotherapy

In order to evaluate the effect of immunotherapy on subpopulations of lymphocytes, peripheral blood mononuclear cells were fractionated into T and non-T cells by incubating in anti-immunoglobulin-coated plates. T cells were further fractionated into rye grass antigen-adherent and nonadherent fractions and human serum albumin (HSA)-adherent and nonadherent fractions by incubating in rye grass antigen-coated and HSA-coated plates, respectively. The mean rye antigen-stimulated proliferative response of rye antigen-adherent fraction was significantly lower than that of rye antigen-nonadherent fraction in patients with rye grass hay fever receiving immunotherapy. There was no difference in the rye antigen-stimulated proliferative response between the HSA-adherent and nonadherent fractions. Both the rye antigen-adherent and nonadherent fractions proliferated similarly when they were stimulated by an unrelated antigen, Candida albicans. The rye antigen-stimulated proliferative response of rye antigen-nonadherent cells could be suppressed by coculturing with rye antigen-adherent cells from patients receiving immunotherapy. Furthermore, the treatment of cocultures with monoclonal antibody against suppressor-cytotoxic T cell (OKT8) subpopulation and guinea pig serum complement reversed the suppression. In patients receiving no immunotherapy, there was no difference in the rye grass antigen-stimulated proliferative response between the rye antigen-adherent and nonadherent fractions. These results suggest that immunotherapy induces a subpopulation of T cells that are adherent to antigen-coated plates and are capable of suppressing T cell proliferation stimulated by the specific antigen.