Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School

Biology and Microbiology

First Advisor

David J. Hurley


This study and studies done by Cutler (1995) and Herold (1995), have utilized well characterized bacterial toxins to provide a model that can be used to test veterinary bacterial isolate products for immunomodulatory effects in cattle. Further, this study demonstrated that bacterial toxins can exert immunomodulatory effects other than those of superantigens. We found that there are three categories, other than superantigens, by which bacterial toxins can exert immunomodulatory control. The first of these induces mitogenesis of T cells utilizing the cytokine interleukin-2 (IL-2) to drive the proliferation. PT falls into this category. The second category includes toxins that are anti-mitogenic and do not induce the production of IL-2. CT was the only toxin tested that fits into this category. The last category contains toxins that are anti-mitogenic, but induce the production of IL-2. This group appears to have the ability to uncouple some portion of the second messenger pathway and inhibit T cell activation. Both STa and PTA are in this group. This study in combination with others done in our laboratory should establish a model by which other toxins from more relevant bacteria can be tested to determine their potential immunomodulatory effects in cattle.

Library of Congress Subject Headings

Bacterial toxins
Cattle -- Immunology




South Dakota State University



Rights Statement

In Copyright