T lymphocytes play an integral role in both cellular and humoral immune responses, carrying out direct effector functions such as cytolysis as well as mediating regulatory functions via secreted lymphokines. T cell activation antigen can be defined only in operational terms: development of functional activity, lymphokine production, or proliferation. The antigen receptor accounts for the specificity of T cell responses. Antigenic stimulation induces lymphokine secretion, including interleukin 2 (IL-2), and also causes an increase in the number of cell surface receptors for IL-2 which, in turn, augments the proliferative response produced by IL-2. The biochemical events which follow stimulation of T cells have not been fully characterized. T cell responses are modulated in a variety of ways. IL-2 has a profound immunoregulatory effect on the cell which produces it: When cells which secrete IL-2 are exposed to IL-2, they become unresponsive to antigen. Gamma interferon acts on macrophages to increase expression of class II major histocompatibility antigens which are required for effective antigen presentation. Resting macrophages secrete apoprotein E which has profound inhibitory immunoregulatory activity; this secretion is reduced when macrophages are stimulated. Thus, there are several feedback pathways that can influence T cell responses. We intend to characterize the cellular and biochemical processes which are associated with activation of T lymphocytes. In particular, we want to distinguish between those events that are initiated by stimulation with antigen and those that are induced by lymphokines such as IL-2. We also intend to characterize the processes involved in the negative regulation of T cell responses. In particular, we want to determine the basis for unresponsiveness to antigen which is induced when cloned murine T cells are exposed to IL-2. We also want to determine the role of apoprotein-E, produced by macrophages, in the regulation of the response of T cells. In these studies, we will use cloned T cells, fixed antigen-presenting cells, monoclonal antibodies, and lymphokines produced by recombinant DNA technology. Thus, discriminating model systems are available for studying the metabolic events induced by specific stimuli.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI018061-08
Application #
3127652
Study Section
Allergy and Immunology Study Section (ALY)
Project Start
1982-05-01
Project End
1990-04-30
Budget Start
1989-05-01
Budget End
1990-04-30
Support Year
8
Fiscal Year
1989
Total Cost
Indirect Cost
Name
University of Chicago
Department
Type
Schools of Medicine
DUNS #
225410919
City
Chicago
State
IL
Country
United States
Zip Code
60637
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