Comparative mitogenic response of old and young rhesus monkey T cells to lectin from Erythrina cristagalli

The lectin (EC) from the coral tree, E. cristagalli, while less mitogenic on a molar or weight basis than PHA or ConA, strongly activates both Rhesus monkey and human T cells. The optimal mitogenic concentrations for both Rhesus and human T cells are 0.25, 2.5, and 25 micrograms/ml, respectively, for PHA, ConA, and EC. Aged Rhesus T cells were profoundly suppressed in mitogenic response to EC (approx. 80%) compared to young Rhesus cells. However, in the presence of supplemental interleukin 2 (20 U/ml), the age-related defect was reversed; the average mitogenic response of the old Rhesus T cells was increased sixfold.