Document Type

Thesis - University Access Only

Award Date

1995

Degree Name

Master of Science (MS)

Department / School

Biology and Microbiology

First Advisor

David J. Hurley

Abstract

Colostrum is an indispensable component of neonatal protection following birth. Although the function of maternal antibodies in colostrum has long been understood, the role of transferred maternal lymphocytes has yet to be defined. In order to comprehend the function of these cells, they must first be characterized. We have begun to characterize these cells by comparing them to their apparent precursor cells, peripheral blood lymphocytes. We examined the proliferative differences of bovine peripheral blood lymphocytes (PBL) and colostral lymphocytes (CL) using three different plant lectins. We found PBL responded with 10 times the magnitude of CL. We also used colostral whey to determine if the colostral environment caused PBL to responded in a similar fashion to colostral lymphocytes. Our studies indicated that the proliferative response of PBL was inhibited by treatment with colostral whey. Colostral whey demonstrated an inhibitory effect on PBL mitogenic responsiveness when added directly to mitogen assays or when placed in culture with PBL for 24 hours prior to stimulation. However, the inhibitory effects appeared to be nearly completely reversed if colostral whey was removed from PBL 24 hours prior to stimulation with mitogens. The binding of flourescein isothiocyanate (FITC) labelled lectins was also examined. We observed that colostral whey inhibited the binding of lectins when added directly to the staining assay or when PBL treated with colostral whey for 24 hours prior to staining were used. The inhibitory effects appeared to be completely reversed when colostral whey treated PBL were removed from colostral whey 24 hours prior to staining. Finally, we studied the effects of colostral whey on PBL cell surface marker expression. We discovered that colostral whey when cultured with PBL for 24 hours caused a significant increase in the number of cells expressing lymphocyte surface antigens CD2, CD3, CD6, and IL-2R, and a decrease in major histocompatibility complex (MHC) Class II expressing populations. It also caused an up regulation of the receptors MHC Class I, MHC Class II, and IL-2R on cells already expressing these molecules. The effects of colostral whey on surface antigen expression, with the exception of IL-2R, were also found to be reversible when colostral whey treated PBL were allowed to recover for 24 hours prior to staining. IL2R stayed partially up regulated even after colostral whey was removed. In contrast to the other findings, cells expressing γ8TCR were dramatically increased upon removal of colostral whey. Our studies have demonstrated that the colostral environment does change the function and phenotypic expression of PBL. They also demonstrated that the effects imposed upon PBL by the colostral environment were transient. Future research will entail studies of colostral lymphocytes in vivo to determine their trafficking patterns within the neonatal animal.

Library of Congress Subject Headings

Calves -- Immunology
Colostrum
Lymphocytes
Maternally acquired immunity

Format

application/pdf

Publisher

South Dakota State University

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Rights Statement

In Copyright