ALTERATION OF T-CELL FUNCTIONS BY INFECTION WITH HTLV-I OR HTLV-II

Two functionally different types of human T-cell clones, 1 with helper function and 2 with specific cytotoxic activity, were infected with different isolates of HTLV-I and HTLV-II. Both types of human T cells showed alterations in specific function after infection with either of the HTLV subgroups. Before HTLV infection, the T-cell clone with helper function proliferates and provides help to B cells only in the presence of a specific soluble antigen (keyhole limpet hemocyanin) and histocompatible antigen-presenting cells. After HTLV infection, these cells respond with increased proliferation and indiscriminant stimulation of polyclonal Ig production by B cells, regardless of the histocompatibility of the antigen-presenting cells or the presence of the soluble antigen. Infection of the normal cytotoxic T-cell clones led to a diminution or loss of the cytotoxic function. Some possible mechanisms for induction of immune deficiency and of polyclonal B-cell activation by viruses of the HTLV family are suggested.