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Factors contributing to T cell persistence in a tolerizing tumor environment

Thesis (Ph. D.)--Harvard-MIT Division of Health Sciences and Technology, 2010. / Cataloged from PDF version of thesis. / Includes bibliographical references. / Cancer is a leading cause of death worldwide, accounting for at least 10% of all deaths globally. Current therapies for cancer include surgical excision, chemotherapy and immunotherapy. CD8[+] T cells are adaptive immune cells responsible for eradicating tumor cells. However, these T cells can be rendered ineffective through tolerance. Yet in various mouse models and human patients, tolerant T cells persist. The aim of this project is to identify factors that support T cell persistence in a tolerizing tumor environment. Using a spontaneous prostate cancer model, we study antigen-specific T cells that have been shown to be locally tolerant in the prostate tumor environment. In this thesis, I compare the immune response in normal, antigen bearing, tumor transgenic and tumor-antigen transgenic mouse models. Results show that T cell infiltration and persistence in the tolerizing prostate environment is dependent on the presence of antigen and tumorigenic/tumor-related factors. Although antigen-specific T cells are locally tolerant in the prostate of tumor-antigen transgenic mice, they generally persist in the prostates of tumor transgenic mice regardless of whether antigen is present or not. Further analyses revealed that T cells infiltrate the prostate and can proliferate extensively in the tolerizing tumor environment due to the presence of antigen. Interestingly, antigen-specific T cells are depleted from the spleens of mice that express antigen in their prostates. / (cont.) This depletion from the spleen is correlated with low levels of IL-7R[alpha] expression and the presence of antigen in the prostate. Tumorigenic or tumor-related factors in the prostate also appear to be supporting CD8[+] T cell persistence. This thesis shows that persistence of antigen-specific T cells in the tumor environment is not dependent on IL-15 and IL-7; cytokines known to support proliferation and maintenance of persisting functional CD8[+] T cells. Some potential candidates are also discussed. More investigative work needs to be done to identify the role of these factors on T cell infiltration and persistence. In combination with tolerance-breaking strategies, persisting T cells may be excellent vehicles for delivering site-specific cancer immunotherapy. / by Mobolaji 0. Olurinde. / Ph.D.

Identiferoai:union.ndltd.org:MIT/oai:dspace.mit.edu:1721.1/58180
Date January 2010
CreatorsOlurinde, Mobolaji O
ContributorsJianzhu Chen., Harvard University--MIT Division of Health Sciences and Technology., Harvard University--MIT Division of Health Sciences and Technology.
PublisherMassachusetts Institute of Technology
Source SetsM.I.T. Theses and Dissertation
LanguageEnglish
Detected LanguageEnglish
TypeThesis
Format154 p., application/pdf
RightsM.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission., http://dspace.mit.edu/handle/1721.1/7582

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