Polyclonal B-cell activation by influenza A/Texas virus-specific human T-cell clones

A previously described proliferating class-II-restricted CD4+ human T-cell clone (TA4) specific for the N2 neuraminidase of the influenza A/Texas virus was tested for its ability to induce B cells to polyclonal immunoglobulin (Ig) production. The data reported in the present study show that, when stimulated by T-depleted autologous peripheral blood mononuclear cells (E-) and A/T virus, the TA4 clone was able to induce B cells to polyclonal Ig production. This effect was also seen using another class II-restricted human T-cell clone specific for the H3 haemagglutinin of the A/Texas virus and autologous polyclonal T cells. This Ig production was MHC-restricted at the inductive level, i.e., the stimulating-virus-treated E- population and the clones or the T cells had to share the same HLA-DR determinants. However, the responding B cells could be allogeneic provided the helper T cells were activated in the presence of autologous irradiated virus-infected E- cells.