22 research outputs found

    Tim-3+ T-bet+ Tumor-Specific Th1 Cells Colocalize with and Inhibit Development and Growth of Murine Neoplasms

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    Abstract Although T cells infiltrate many types of murine and human neoplasms, in many instances tumor-specific cytotoxicity is not observed. Strategies to stimulate CTL-mediated antitumor immunity have included in vitro stimulation and/or genetic engineering of T cells, followed by adoptive transfer into tumor-bearing hosts. In this model of B cell lymphoma in SJL/J mice, we used Tim-3+ T-bet+ Th1 cells to facilitate the development of tumor-specific CTL. Tumor-specific Th1 cell lines were polarized with IL-12 during in vitro stimulation and long term maintenance. As few as 5 million Tim-3+ T-bet+ Th1 cells enabled recipients to resist growth of malignant transplantable cells. In addition, similar numbers of Th1 cells injected into 2- to 3-mo-old mice inhibited development of the spontaneous primary lymphomas, which normally arise in 90% of aging mice. CFSE+ Th1 cells colocalized with injected tumor cells in vivo and formed conjugates with the tumor cells within follicles, whereas in nontumor-challenged recipients the CFSE+ Th1 cells localized only within the T cell zones of the spleen. These results provide evidence that adoptive immunotherapy with Tim-3+ T-bet+ tumor-specific Th1 cells can be used to induce host cytotoxic responses that inhibit the development and growth of neoplastic cells

    Beyond the Biomedical: Preexposure Prophylaxis Failures in a Cohort of Young Black Men Who Have Sex With Men in Atlanta, Georgia

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    In a cohort of young black men who have sex with men, we observed high human immunodeficiency virus incidence despite education and access to preexposure prophylaxis (PrEP). Although PrEP has efficacy in clinical trials, we identify barriers to real-world effectiveness. Human immunodeficiency virus (HIV) preexposure prophylaxis (PrEP) has high biomedical efficacy; however, awareness, access, uptake, and persistence on therapy remain low among black men who have sex with men (BMSM), who are at highest risk of HIV in the United States. To date, discussions of “PrEP failure” have focused on one typology: rare, documented HIV acquisitions among PrEP users with adequate serum drug levels (ie, biomedical failure). In our cohort of HIV-negative young BMSM in Atlanta, Georgia, we continue to observe a high HIV incidence (6.2% annually at interim analysis) despite access to free PrEP services. Among 14 seroconversions, all were offered PrEP before acquiring HIV. Among these participants, we identified 4 additional typologies of PrEP failure that expand beyond biomedical failure: low PrEP adherence, PrEP discontinuation, PrEP contemplation without initiation, and PrEP refusal. We describe the 5 typologies and suggest interventions to improve PrEP effectiveness among those at highest risk
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