T-lymphocyte invasiveness: control by voltage-gated Na⁺ channel activity

Whole-cell patch-clamp recordings showed that a sub-population (10%) of Jurkat cells, a model of human T-cells, expressed a functional voltage-gated sodium channel, which was tetrodotoxin (TTX)-resistant. Expression of voltage-gated sodium channel protein was confirmed by western blots. Semi-quantitative PCR analysis revealed that mRNAs for the α-subunits of multiple voltage-gated sodium channel subtypes were present but indicated that Na_v1.5 was the predominant subtype, consistent with the TTX-resistant nature of the recorded currents. Importantly, 10 μM TTX reduced the number of Jurkat cells invading a Matrigel basement membrane by 93.0±5.5%. Since similar sodium channels have also been detected in normal human T-lymphocytes, it is concluded that the activity of voltage-gated sodium channels could represent a novel mechanism potentiating the invasive capacity of these cells.