Publication Date

2014

Document Type

Thesis

Committee Members

Nancy Bigley (Advisor), Barbara Hull (Committee Member), Eric Vela (Committee Member)

Degree Name

Master of Science (MS)

Abstract

Cytokine activation of macrophages leads to "macrophage polarizatio" The M1 subset is polarized by exposure to lipopolysaccharide (LPS) and interferon-gamma (IFN-γ) and M2 polarized cells develop after exposure to interleukin-4 (IL-4) or IL-13. In this study, the RAW 264.7 murine macrophage cell line was used to study the effect herpes simplex virus-Type I (HSV-1) and Dengue virus serotype-2 (DENV2) infections have on cultures of unpolarized (M0) or polarized subsets. The macrophage subsets were characterized using cluster of differentiation markers CD14 and CD86. Uninfected M1 macrophages showed up regulation in expression of the co-stimulatory factor B7.2 (CD86) compared to expression by M0 or M2 macrophages. M1 macrophages exhibited distinct morphological and viability features including presence of vacuoles, strong adherence, enlargement of cell body and significant decrease in cell viability at 24 hours following exposure to LPS and IFN-γ. Infection with either HSV-1 or DENV-2 induced a down regulation in expression of CD86 by M1 cells and an up-regulation of expression in M0 and M21 cells. Immunofluorescence analysis using flow cytometry showed a decrease in CD86 expression levels in only M1 cells by 24 hours following infection with either infected with HSV-1 or DENV2. Virus-infected M1 macrophages showed further decreases in cell viability compared to viabilities of infected M0 or M2 macrophages. In unpolarized and polarized macrophages in this study, SOCS 3 expression was highest in M0 and M2 cell prior to and after infection with either HSV-1 or DENV2. In these same cell populations higher cell viabilities were observed at 12 and 24 hours after infection as well as higher viral titers by 24 hours post infection. In contrast, the M1 macrophage populations showed lesser increases in SOCS 3 expression, markedly decreased cell viabilities and 2.8fold decrease in viral titers by 24 hour after infection with HSV-1. These observations suggest that the ameliorating effect of SOCS3 on inflammation in the M0 and M2 macrophages permitted both a slower decline in cell viabilities and enhanced viral replication in these isolated cell populations. Cells converted to the M1 phenotype rapidly diminished viral replication and cell viability.

Page Count

87

Department or Program

Microbiology and Immunology

Year Degree Awarded

2014

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