Document Type

Thesis - University Access Only

Award Date

1994

Degree Name

Master of Science (MS)

Department / School

Biology and Microbiology

First Advisor

David J. Hurley

Abstract

Glucocorticoids and other stress hormones have demonstrated effects on the humeral and cellular components of the immune system. Dexamethasone (Dex), a synthetic glucocorticoid, is used frequently for inflammatory management in both humans and animals. We have investigated the effects of Dex on the physiology and function of bovine peripheral blood lymphocytes and in two continuous murine T cell lines, one sensitive (LBRM) and one insensitive (EL4) to Dex. We have compared these cellular models to identify the effects of stress hormones in development of immune stasis. Our results identified changes in viability after long-term and short-term exposure to Dex, as well as specific changes in nuclear morphology and inhibition of cell proliferation. We observed that continuous exposure to Dex induced little change in the viability of PBL. However, short-term exposure to Dex, followed by further culture in unsupplemented medium, resulted in a significant loss of viability. These PBL also exhibited nuclear alterations, consistent with apoptosis, including DNA condensation and decreased fluorescence with the nucleic acid dye, acridine orange. Finally, the mitogenic response of Dex-treated PBL was depressed as compared to controls. Our studies have demonstrated that apoptosis of mature lymphocytes is a likely mechanism leading to immune suppression associated with stress and its products. Future research will entail understanding the roles of cytokine and membrane alterations m the PBL response to stress.

Library of Congress Subject Headings

Cattle -- Effect of stress on
Cattle -- Immunology
Apoptosis
Lymphocytes

Format

application/pdf

Publisher

South Dakota State University

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Rights Statement

In Copyright