Separation and characterization of a subset of human T8+ cells which function as antigen-presenting and contrasuppressor cells.

The lectin Vicia villosa (VV) binds preferentially a subset of T cells. Separated VV-adherent cells (AC) do not generate helper function alone, but when added to VV-non-adherent cells (NAC), they can present streptococcal antigen (SA) and induce helper function as effectively as monocytes, at a ratio of 1 VV-AC to 4 VV-NAC. Further separation into a T8+ subset of VV-AC and reconstitution with T4+ helper cells (HC) has established that the T8+ VV-AC induces T4+ cells to helper activity. However, in addition to antigen presentation, the T8+ subset of VV-AC has a contrasuppressor function, for it can prevent T8+ suppressor cells from inhibiting T4+ HC function. The results suggest that a T8+ subset can present antigen to T4+ HC, activate helper function and prevent suppression. The T8+ VV-AC may have considerable biological significance in its dual function of countering the dominant suppressor activity and presenting antigen to induce helper activity.