Defense Date

2011

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Microbiology & Immunology

First Advisor

Michael McVoy

Abstract

Congenital cytomegalovirus infection is the leading cause of sensorineural hearing loss in the U.S. CMV vaccines developed to date do not protect the majority of women of childbearing age from primary CMV infection. Insufficient vaccine-induced epithelial entry neutralizing activity may be the reason for poor performance of these vaccines. CMV entry into endothelial and epithelial but not fibroblast cells requires the virion envelope complex gH/gL/UL128-131. Since current vaccines do not target this complex, epithelial entry mediators UL128-131 are attractive subunit CMV vaccine candidates, since they should target mucosal immunity. The mucosal immune response, specifically salivary epithelial entry neutralizing activity, has not been previously described. This report demonstrates that salivas from CMV seropositive children under two, adolescents, and Towne vaccine recipients do not have epithelial or fibroblast neutralizing activity. Epithelial but not fibroblast neutralizing activity was identified in half of the salivas from CMV seropositive adults tested. This activity correlated with the level of serum neutralizing activity, suggesting that salivary neutralizing activity results from passively transferred serum IgG. Furthermore, this report describes three highly immune individuals with serum and saliva neutralizing titers two- to four-fold above average. These individuals also have UL130 antibodies detectable in western blot assays. This is the first report of antibodies by western blot in CMV seropositive sera to UL128, UL130, or UL131. To determine the feasibility of UL128-131 as vaccine candidates both peptide and DNA vaccines were tested in animal models. Rabbit anti-peptide sera from UL130 and UL131 vaccinated animals induced epithelial entry neutralizing activity similar to that found following natural infection. Mixing anti-peptide UL130 and UL131 sera neutralized CMV infection of epithelial cells at titers higher than natural infection. DNA vaccination with these proteins was not as successful but based on DNA vaccination of mice UL130 is the most immunogenic of the three proteins. These data support further development of UL130 as a CMV vaccine. Future vaccines, including the vaccine candidates described in this report, should strive to induce levels of immunity seen in the three highly immune individuals, specifically serum epithelial neutralizing titers >1:7,000 and saliva epithelial neutralizing titers >1:20.

Rights

© The Author

Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

June 2011

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