Appearance of non-specific suppressor T cells during in vitro culture.

It was found that when normal mouse spleen cells were cultured for 4 days they were capable of non-specifically suppressing the in vitro antibody response of non-precultured spleen. The suppression was mediated by a subpopulation of viable, non-adherent, T lymphocytes with the surface phenotype Ly-1+, Ly-2- and Ia-. Furthermore, it appeared that the suppressor cells were responding to foetal calf serum antigens present in the tissue culture medium and were subsequently inactivating either B lymphocytes or accessory cells required for antibody formation, which had passively absorbed these antigens.