Voltage‐dependent K+ channels in Immunogenic and Regulatory Functions of Lung Dendritic Cells

Abstract

Dendritic cell (DC) subsets display different functional roles in regulating immune responses. We identified two DC populations, CD11clowCD11bhigh and CD11chighCD11blow, in the lungs of asthmatic mice. The DC subsets show distinct expression patterns in their surface markers and chemokine receptors. Since K+ channels modulate the function of T‐lymphocytes and mast cells, we examined ion channel expression of both DC subsets using whole‐cell voltage‐clamp techniques. At least two types of voltage‐dependent K+ currents were detected in both DCs, demonstrated by differential inhibitory effects of the selective Kv1.3 blocker, margatoxin, and the non‐selective voltage‐sensitive Ca2+‐activated K+ channel blocker, charybdotoxin. Voltage‐dependent proton currents were also detected in both DCs, and this was blocked by 10 mM Zn+. This suggests the potential role of lung DCs in the phagocytosis through activating the NADPH oxidase. The CD11clowCD11bhigh DCs exhibited significantly larger amplitudes in all current than CD11chighCD11blow DCs (p<0.01), suggesting that CD11clowCD11bhigh DCs possess a higher ion channel expression level in the membrane. This differential expression level of ion channels may shed light on the distinct functional properties between the two DC subsets and their migration to the lymph node during allergic immune response.(Supported by LB506 DHHS State of Nebraska cancer and Smoking‐related Disease Program)