Abstract
This chapter summarizes some of the salient features of viral immortalization of human T lymphocytes and the status of knowledge on the herpesvirus and retrovirus oncogenes functional in these cells. The permanent T cell replication that these viruses can induce is accompanied by and probably caused by the induction and maintenance of an activated state of the infected cell. This type of T cell activation is likely to bypass the components of the normal activation pathway that normally initiates with ligand binding to surface receptors. The capacity for the immortalization of human T cells in vitro has proved useful for the investigation of cellular immunity, T cell signaling, lymphoproliferation, and leukemogenesis. Herpesvirus saimiri C strains allow direct functional comparison of transformed and nontransformed cells of the same origin. The use of immortalized T cell lines for studies of T cell signaling avoids the problems caused by contaminating feeder cells or by accessory cells present in preparations of fresh lymphocytes. The transforming potential of both the proteins is not restricted to T cells, whereas Tax is needed for viral replication, Stp is nonessential with respect to multiplication of virus in cell culture.
