Molecular signaling mechanisms in T-lymphocyte activation pathways: a review and future prospects

Understanding of the molecular mechanisms which drive the complex activation responses of T lymphocytes was previously limited. However, current studies in lymphocytes, and in other cells, have indicated the involvement of several secondary messenger or signal systems, and recent progress in elucidating the relevant pathways has been extraordinarily rapid. This review therefore attempts to provide an overview of these processes--including the effects of Ca2+, hydrolysis of phospholipids, arachidonic acid, Ca2+/phospholipid-dependent and tyrosine kinases, calmodulin, cyclic nucleotides, ion channels, and adherent cells--and their roles in weaving a subtle and highly responsive web of regulatory signals.