Lymphocyte activation by Con A.

Con A can activate cytotoxic effector cells, helper cells and suppressor cells. In all cases Con A activates polyclonally and thus the entire T cell repertoir can be revealed by Con A activation. Nylon purified T cells cannot be activated by Con A. however, in the presence of helper cells, such as adherent cells, or in the presence of serum from several species, Con A activates purified T cells. The serum factors that are responsible for Con A activation of purified T cells are present in the albumin fraction. It is suggested that Ia molecules may be responsible for the ability of Con A to activate purified T cells and a general hypothesis for T cell activation is outlined.