Activation of CFTR chloride current by nitric oxide in human T lymphocytes.

Nitric oxide, which is produced by cytokine‐activated mononuclear cells, is thought to play an important role in inflammation and immunity. While the function of nitric oxide as a direct cytotoxic effector molecule is well established, its function as a transducer molecule in immune cells is not. By use of whole‐cell patch clamp recordings, we show that nitric oxide activates cystic fibrosis transmembrane conductance regulator CI‐ currents in normal human cloned T cells by a cGMP‐dependent mechanism. This pathway is defective in cystic fibrosis‐derived human cloned T cells. These findings not only delineate a novel transduction mechanism for nitric oxide but also support the hypothesis that an intrinsic immune defect may exist in cystic fibrosis.