Binding activity to the HIV enhancer, a sequence highly homologous to the NF-KB enhancer, is inducible by PMA in human Jurkat T cells. We here show that, similar to what is observed for NF-KB in B cells, mild detergents, such as Deoxycholate, reveal a cryptic binding activity in protein extracts from non activated cells. The complex revealed by detergent treatment correspond to the PMA inducible, highly sequence specific species. This result suggest the existence of an inhibitor in non activated cells, which is released by the detergent, as has been demonstrated in B cells. Mild detergent treatment of PMA activated extracts resulted in superinduction of the specific complex. These results suggest that regulation of HIV enhancer binding protein is similar to regulation of NF-KB in B cells.