The discovery of a diverse and unique set of ion channels in T lymphocytes
has led to a rapidly growing body of knowledge about their functional roles
in the immune system. Here we review the biophysical and molecular charact
erization of K+, Ca2+, and Cl- channels in T lymphocytes. Potent and specif
ic blockers, especially of K+ channels, have provided molecular tools to el
ucidate the involvement of voltage- and calcium-activated potassium channel
s in T-cell activation and cell-volume regulation. Their unique and differe
ntial expression makes lymphocyte K+ channels excellent pharmaceutical targ
ets for modulating immune system function. This review surveys recent progr
ess at the biophysical, molecular, and functional roles of the ion channels
found in T lymphocytes.