The role of monovalent cations in the interaction between the cytotoxic T lymphocyte and its target.

Evidence is provided for the participation of monovalent cations in both the binding and lytic phases of the lytic cycle. There appears to be one sodium requirement in the cytotoxic T lymphocyte-target binding event (effective dose 50 approximately 35 mM) and possibly another sodium requirement in the delivery of the lethal hit (ED50 less than 7 mM). Potassium can replace sodium in the binding event but antagonizes the lethal hit phase (inhibitory dose 50 approximately 110 mM). Lithium antagonizes the binding event (ID50 approximately 15 mM).