The T lymphocyte activation scheme is set in motion by the interaction of processed antigen in context of MHC products with the T lymphocyte receptor for nominal antigen which is closely associated with the pan T cell antigen, T3 (Leu-4, CD3). Antibodies directed against either the T cell receptor or T3 mimic antigen and lead to changes consistent with the activated state. This activation appears to be dependent upon the phospholipase C- catalyzed generation of the second messengers, inositol 1, 4, 5- trisphosphate and diacylglycerol. Inositol trisphosphate increases intracellular calcium concentration by releasing Ca++ from intracellular stores while diacylglycerol activates protein kinase C. We recently have shown that other inositol polyphosphates, particularly inositol tetrakisphosphate and inositol 1, 3, 4- trisphosphate, are produced as a consequence of perturbation of the T cell receptor-T3 complex. In this proposal, we outline a series of experiments designed to investigate the molecular mechanisms which control inositol polyphosphate formation in T lymphocytes following stimulation of the T cell receptor-T3 complex. We will investigate control of antigenic signal transduction by guanine nucleotide-binding regulatory proteins. These G-proteins, which regulate adenylate cyclase activity, recently have been implicated in control of phospholipase C activity as well. We shall investigate the regulatory roles of eicosanoids, particularly PGE2, and the well defined pan T cell surface antigen, T1, in the early events of T lymphocyte activation. Finally, we shall attempt to implicate inositol phosphate production as a mechanism of T lymphocyte activation by oxidants. Using the techniques of cellular electrophysiology, we will explore ion channel events in T lymphocyte activation including the possibility of inositol tetrakisphosphate or inositol 1, 3, 4-trisphosphate control of K+ or Ca++ ion channel activity. These studies should significantly improve our understanding of the phenomenon of T lymphocyte activation and have broad implications for control of immunological events and cellular proliferation including neoplasia.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29GM038610-02
Application #
3466331
Study Section
Cellular Biology and Physiology Subcommittee 1 (CBY)
Project Start
1987-09-01
Project End
1992-08-31
Budget Start
1988-09-01
Budget End
1989-08-31
Support Year
2
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Vanderbilt University Medical Center
Department
Type
Schools of Medicine
DUNS #
004413456
City
Nashville
State
TN
Country
United States
Zip Code
37203