recombinant interleukin 2 ( il-2 ) failed to augment the [ 3h ] thymidine uptake by these b cells despite the low density expression of tac antigen ( il-2 receptor ) on their cell surface , or even when the cells were stimulated with phorbol myristate acetate ( pma ) to express higher density of tac antigen ( 48 % ) .
C0699040
cell surface
C0007634
cells