Herpes simplex virus type 1 (HSV-1) is a ubiquitous human pathogen that establishes a latent infection in sensory ganglia and upon reactivation, can cause severe ocular disease. During lytic replication, viral proteins are expressed in a temporal cascade of immediate early (α), early (β) and late (γ) genes. The γ genes are further sub-classified into γ1 genes which are expressed prior to DNA replication and γ2 genes which are absolutely dependent on DNA replication for their expression. During a latent infection of the trigeminal ganglia (TG), no infectious virus is produced and latency is associated with a persistent virus-specific CD8+ T cell infiltrate that actively block reactivation. In C57BL/6 mice, approximately 50% of these CD8+ T cells are specific to a single epitope on a γ1 protein glycoprotein B (gB498-505; gB-CD8). In the TG, gB-CD8 are retained with an activated phenotype suggesting recent exposure to antigen during abortive reactivation events. While the kinetics of gene expression during lytic infection has been appreciated for some time, little is known about antigen expression during latency and reactivation, and its influence on antigen-specific CD8+ T cells in the TG. Using gB as our model antigen, in this work we show that during reactivation, gB expression occurs much sooner than gC expression, indicating that it expressed fairly early even during reactivation. Furthermore, by delaying gB expression to after DNA replication we observed a severe impairment in viral replication in the TG and a significant diminishment in the retention and activation phenotype of gB-CD8 in latently infected TG. However delaying gB did not prevent the ability of gB-CD8 to block reactivation indicating they can act very quickly even after DNA replication. Finally we demonstrate that by mutating the gB epitope such that it does not induce a gB-CD8 response, we abrogate the gB-CD8 infiltrate in the TG. These studies all demonstrate that during an HSV-1 infection, only antigen-specific CD8+ T cells infiltrate the TG and antigen exposure during latency is responsible for their retention in the TG. This work has great implications toward designing better immunogens for therapeutic vaccines to prevent HSV-1 reactivation.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-05282010-095835 |
| Date | 08 June 2010 |
| Creators | Ramachandran, Srividya |
| Contributors | Ted Ross, Joanne Flynn, Ph.D/, Karen Norris, Ph.D, Robert Hendricks, Ph.D., Paul Kinchington, Ph.D |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-05282010-095835/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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