Human monocyte‐depleted peripheral blood mononuclear cells were separated in T4+and T8+populations by a panning technique. Petri dishes coated with goat anti‐mouse antibodies were plated by peripheral blood mononuclear cells coated by monoclonal antibodies, either T4 or T8. The cell populations were separated into adherent and non‐adherent populations based on binding to the goat anti‐mouse‐coated plastic dishes. The purity of the adherent populations was 96%. T4+and T8+populations were used as effector cells in the concanavalin A‐induced suppressor test. The T4+population revealed a pronounced suppressor activity similar to that exhibited by the T8+population. This finding was independent of two different sources of monoclonal antibodies, T4/T8 and OKT4/OKT8. The registered suppressor activity in the monoclonal antibody‐defined helper population could not be explained either by a switch of the membrane phenotype from T4+to T8+cells or by an increased interleukin 2 consumption of the concanavalin A