T cell blast stimulation of MLR: role of interleukin 1 and interleukin 2.

T cells blasts were examined for the ability to stimulate primary mixed leucocyte reactions (MLR) in the presence or absence of supplemental interleukin 1 (IL-1) or interleukin 2 (IL-2). After purification, resting T cells were activated using monoclonal anti-CD3 antibody in an accessory-cell free systems. After irradiation, such cells were found to be non-stimulatory in autologous or allogeneic MLR except in the presence of supplemental IL-2. IL-1 was an ineffective cofactor, despite its ability to enhance anti-CD3 mediated stimulation of T cells. It is concluded that T cell blasts may lack an essential factor needed to stimulate IL-2 secretion (other than IL-1), or may elicit responses only from allogeneic T cells not bearing IL-1 receptors.