Cloned natural suppressor cell lines express the CD3⁺CD4^-CD8^- surface phenotype and the α,β heterodimer of the T cell antigen receptor

Several cloned lines of natural suppressor (NS) cells were studied for their expression of the TCR complex. Almost all bore the CD3⁺CD4^-CD8^- surface phenotype with the α,β TCR as judged by immunofluorescent staining. Immunoprecipitation experiments showed a spot on two-dimensional gels which is characteristic of the TCR heterodimer, but neither γ- nor δ-chains could be precipitated with the appropriate antibodies. NS cells were stimulated to proliferate in vitro with anti-CD3 antibodies and PMA in the presence of irradiated spleen cells. However, anti-CD3 antibodies did not inhibit the suppressive activity of the NS cells. The role of the TCR complex in the suppressive function of these cells remains to be elucidated.