Most new human immunodeficiency virus (HIV) infections are acquired through vaginal or rectal mucosa, and gut mucosal tissue is a primary target of HIV infection. To generate mucosal immunity against HIV or its simian counterpart simian immunodeficiency virus (SIV), the Gram positive bacterium Clostridium perfringens was used to develop a vaccine that delivers SIV p27 to the gut and induces local T cell immunity.
Under in vitro conditions, Clostridium perfringens expressing SIV p27 (Cp-p27) was found to induce dendrite cell (DC) maturation and stimulate p27-specific T cell responses. To improve intracellular delivery of p27 to DCs and thereby enhance immune priming, Cp-p27 variants expressing p27 conjugated with protein transduction domains (PTDs) at the 5 end were constructed. While internalization of p27 by DCs and gut epithelial cells was improved following exposure to the PTD-Cp-p27 variants, cellular p27-specific immune stimulation was not significantly improved compared with wild-type Cp-p27.
The Cp-p27 vaccine was then tested in vivo in mice for its ability to prime gut mucosal T cell responses. First, an adjuvant optimization study with three mucosal adjuvants, cholera toxin (CT), mutant E. coli heat-labile enterotoxin (LT(R192G)), and unmethylated cytosine-phosphate-guanine oligodinucleotides (CpG ODNs) was performed to determine the best T cell immune response in the gut. While the combination of CpG ODNs and (LT(R192G)) induced the highest T cell immune response, (LT(R192G)) alone provided the best multifunctional CD8+ T cell response in the gut.
Oral Cp-p27 vaccination was then tested for induction of T cell immunity in vivo in a prime-boost model by combining Cp-p27 with systemic immunization with an adenovirus expressing p27 (Ad-p27). Cp-p27 vaccination primed a strong multifunctional T cell immune response in gut lamina propria, although it could not stimulate a systemic immune response. In contrast, Ad-p27 vaccination stimulated strong systemic immunity but limited gut mucosal immunity. By sequentially delivering Cp-p27 and Ad-p27, immunity in both the gut and systemic tissues was achieved.
Altogether, this study demonstrates that Cp-p27 can deliver p27 to gut T cells through dendritic cells to prime a strong, multifunctional immune response in the gut effector tissue.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-04102008-114211 |
| Date | 16 April 2008 |
| Creators | Helmus, Ruth Anne |
| Contributors | Phalguni Gupta, PhD, Simon M. Barratt-Boyes, BVSc, PhD, Ronald C. Montelaro, PhD, Bruce A. McClane, PhD, Ted M. Ross, PhD |
| 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-04102008-114211/ |
| 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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