Dissertations and Theses @ UNI

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Open Access Thesis

Keywords

Cytokines; Lymphocytes; Nitrates--Physiological effect; Nitrites--Physiological effect; Academic theses;

Abstract

Approximately 3 million people may be exposed to high nitrate levels(>10 ppm) in the United States, especially in Iowa and other agricultural states. The concern regarding usage of groundwater with excessive concentrations of nitrates is related to human health effects. The toxicity of nitrate to humans is due to the body's reduction of nitrate to nitrite. Nitrate/nitrite impair public health with consequences such as gastric cancer, methemoglobinemia and other diseases. Currently, based upon human case studies, the drinking water quality standard in the U.S. is 10 ppm nitrate-N (MCL). Little work has been done on the effects of nitrate/nitrite on the immune system. Th1/Th2 immune responses are important in host protection and resolution of otherwise potentially fatal disease processes. Th1 cytokines are generally associated with protection against infectious diseases, whereas the production of Th2 cytokines correlates with susceptibility to such diseases but protection from autoimmune disorders. Therefore, a shift from a predominantly Th1 response to a Th2 response may make an individual more susceptible to a variety of infectious diseases. Furthermore, the Th3 cytokine, TGF-{3, might inhibit both Th1 and Th2 responses, or only the Th1 response, and suppress lymphocyte proliferation. In this project, we examined human lymphocytes of different individuals and Jukart cells to study the growth/viability of human peripheral blood mononuclear cells exposed to various concentrations of nitrate/nitrite using the MTT assay. We looked not only at Th1 and Th2 cytokines but we also detected the production of TGF-r by ELISA after exposure of cells to nitrate/nitrite. Our results demonstrate that sodium nitrite produces a significant suppression of mitogen-stimulated T and B lymphocyte proliferation. Sodium nitrate had a lesser effect on the proliferation of lymphocytes. Sodium nitrate and nitrite decreased production of Th1 cytokines and decreased the level of Th2 cytokines in some individuals. Both sodium nitrate and nitrite increased the production of TGF-ß in some of the experiments. This is in agreement with previous findings and other research which indicated that an excess amount of nitrite depressed lymphocyte responses to mitogens and induced a shift from a Th1 to Th2 type of immune response. These individuals might be particularly vulnerable to infectious diseases.

Year of Submission

2003

Degree Name

Master of Science

Department

Department of Biology

First Advisor

Lisa A. Beltz

Second Advisor

Edward Brown

Third Advisor

Kavita R. Dhanwada

Comments

If you are the rightful copyright holder of this thesis and wish to have it removed from the Open Access Collection, please submit a request to scholarworks@uni.edu and include clear identification of the work, preferably with URL.

Date Original

2003

Object Description

1 PDF file (78 leaves)

Language

en

File Format

application/pdf

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