Suppression of T-lymphocyte cytotoxicity following exposure to 60-Hz sinusoidal electric fields

A significant 25% inhibition (P < .005) of allogeneic cytotoxicity of the target cell MPC‐11 by the murine cytotoxic T‐lymphocyte line CTLL‐1 was observed when the 4‐h cytotoxicity assay was conducted immediately following a 48‐h pre‐exposure of the effector lymphocytes to a 10‐mV/cm (rms) 60‐Hz sinusoidal electric field. At 1.0 mV/cm a significant 19% inhibition (P < .0005) was seen. At 0.1 mV/cm a nonsignificant 7% inhibition of cytotoxicity was noted. When the 4‐h cytotoxicity assay was conducted in the presence of the field using previously unexposed effector lymphocytes, cytotoxicity was not significantly reduced. Cell proliferation in the presence of interleukin‐2 was unaffected by the field. These data suggest a dose response and threshold (between 0.1 and 1.0 mV/cm) for inhibition of cytotoxicity in clonal T‐lymphocytes by exposure to a 60‐Hz sinusoidal electric field. These results suggest mechanisms by which 60‐Hz electric fields could affect the function of cells of the immune system.