The helper function of human T4+ cells acting on autologous B cells, in the presence of monocyte-enriched cells (MEC), has been studied using the hapten-carrier conjugate DNP-streptococcal antigen (DNP-SA). The antibody response can be suppressed by T8+ cells, but selection of a Vicia villosa lectin-non-adherent (T8VV-) subset enhances the suppressor function. The T8 Vicia villosa lectin-adherent (T8VV+) cells are not suppressive, rather they inhibit the T8VV- cell suppressor function. Sequential reconstitution studies suggest that the target of both T8VV- suppressor-cell and T8VV+ contrasuppressor activity is the T4 helper-inducer cell. This was established after the separation of T4+ cells into Leu 8- helper- and Leu 8+ suppressor-inducer cells. Activation of T8VV- and T8VV+ cells with antigen before reconstitution with fresh lymphocytes and MEC suggests that T8VV- suppressor activity is antigen specific, whereas T8VV+ cell contrasuppressor function is non-specific. We suggest that the human T8+ cells are functionally heterogeneous and consist not only of suppressor and cytotoxic cells but also contrasuppressor cells.
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