Date of Award

Fall 12-15-2016

Document Type

Thesis

Degree Name

Bachelor of Science (BS)

Department

Biological Sciences

First Advisor

Dr. Lawrence Mylin

Abstract

Cytotoxic (CD8+) and Helper (CD4+) T lymphocytes play an important role in the immune detection and destruction of tumors. The induction of Cytotoxic T cell responses by multiple CD8 epitopes located within the Simian Virus 40 Large Tumor Antigen (SV40 T ag) oncoprotein has been well characterized, and we have begun to characterize the role(s) of CD4+ Helper T cells in controlling cellular immune responses to the SV40 T ag. The goal of this study was to characterize the cytokines produced by activated SV40T ag-specific Helper T cells in order to identify subset(s) of Helper T cells that may differentially influence regulation of the cellular immune response. Mice were immunized with B6/K-145 cells, which express a SV40 T ag mutant in which the CD8 epitopes I, II/III, IV and V have been inactivated.Frequencies of CD4 epitope 381-, 529-and 581-specific T cells expressing the cytokines IFN-, IL-2, or IL-10 were compared using single and double color ELISPOT assays following 24 of 40 hours of in vitropeptide re-stimulation. The data suggests that distinct populations of Helper T cells may secrete IFN-, IL-2 or both cytokines. Additionally, the ratio of IL-10 to IFN-secreting Helper T cells was reduced in the absence accompanying robust Cytotoxic T cell immune response. Our results begin to support a model in which multiple subsets of Helper T cells, potentially TH1 and Treg, work in parallel to coordinate immune responses to cellular tumor antigens.

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