Role of K⁺ Ion Channels in Lymphokine-Activated Killer (LAK) Cell Lytic Function

Abstract

Cells of the immune system possess K⁺ ion channels which have been implicated in various cellular functions including activation, differentiation and cytolytic function. To define the role of K⁺ ion channels in the lytic function of lymphokine-activated killer (LAK) cells, we investigated the effects of K⁺ channel blockers on their cytolytic activity. Results show that when LAK cell mediated cytolysis of AKIL-20 tumor cexis was carried out in the presence of: a) the K⁺ channel blocker, 4-aminopyridine (4-AP); b) the monoamine, serotonin (5-hydroxytryptamine; 5-HT); c) the serotonin agonist, quipazine; d) or the Ca⁺⁺ dependent K⁺ Channel blocker, quinidine, the cytolytic activity of the LAK cells was inhibited in a dose-dependent manner. Preincubation of LAK effector cells also inhibited lysis in a dose-dependent manner, whereas preincubation of the AKIL-20 tumor target cells produced no inhibitory effects. This study demonstrates that K⁺ ion channels are involved in the LAK cell cytolytic process and that compounds, including neuroendocrine products, which modulate K⁺ ion channel function are capable of modulating the lytic activity of these effector cells.