The Interaction of Normal Lymphocytes and Cells from Lymphoid Cell Lines III. STUDIES ON ACTIVATION IN AN AUTOCHTHONOUS SYSTEM.

Activation of fresh blood lymphocytes has been measured by uptake of tritiated thymidine, following exposure to irradiated cells from autochthonous or allogeneic cell lines (LCL cells). Nine autochthonous combinations were studied. In every case activation was observed and in one the rate and peak level of activation were comparable to those found in control allogeneic mixtures. Neither foetal calf serum nor antibiotics appeared to be important factors in the activation process. There was no correlation between the number of identified HL-A histo-incompatibilities in a given allogeneic mixture and the rate or peak level of activation achieved. Activation appears to be influenced by the metabolic state of the LCL cells and the rate of the reaction is sensitive to the precise culture conditions under which it proceeds. Some distinction can be drawn between the antigens responsible for activation in autochthonous and in allogeneic mixtures but the former may prove to be modified histocompatibility determinants. [ABSTRACT FROM AUTHOR]