1. Repeated Vaginal SHIV Challenges in Macaques Receiving Oral or Topical Preexposure Prophylaxis Induce Virus-Specific T-Cell Responses.
- Author
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Tsegaye TS, Butler K, Luo W, Radzio J, Srinivasan P, Sharma S, Aubert RD, Hanson DL, Dobard C, Garcia-Lerma JG, Heneine W, McNicholl JM, and Kersh EN
- Subjects
- Administration, Oral, Administration, Topical, Animals, Drug Combinations, Drug Resistance, Viral, Emtricitabine, Tenofovir Disoproxil Fumarate Drug Combination, Female, Pre-Exposure Prophylaxis, Reassortant Viruses drug effects, Simian Immunodeficiency Virus drug effects, Simian Immunodeficiency Virus immunology, Anti-HIV Agents therapeutic use, Deoxycytidine analogs & derivatives, HIV Infections prevention & control, Macaca nemestrina, Organophosphorus Compounds, Simian Acquired Immunodeficiency Syndrome prevention & control, T-Lymphocytes physiology
- Abstract
Background: Preexposure prophylaxis (PrEP) for HIV prevention is a novel biomedical prevention method. We have previously modeled PrEP during rectal SHIV exposures in macaques and identified that Simian/Human Immunodeficiency Virus chimera (SHIV)-specific T-cell responses were induced in the presence of antiretroviral drugs, an observation previously termed T-cell chemo-vaccination. This report expands those initial findings by examining a larger group of macaques that were given oral or topical PrEP during repeated vaginal virus exposure., Methods: Thirty-six female pigtail macaques received up to 20 repeat low-dose vaginal inoculations with wild-type (WT) SHIVSF162P3 (n = 24) or a clonal derivative with the tenofovir (TFV) K65R drug-resistant mutation (n = 12). PrEP consisted of oral Truvada (n = 6, WT), TFV vaginal gel (n = 6, K65R), or TFV intravaginal ring (n = 6, WT). The remaining animals were PrEP-inexperienced controls (n = 12, WT; n = 6, K65R). SHIV-specific T cells were identified and characterized using interferon γ Enzyme-Linked ImmunoSpot (ELISPOT) and multiparameter flow cytometry., Results: Of 9 animals that were on PrEP and remained uninfected during WT SHIV vaginal challenges, 8 (88.9%) developed virus-specific T-cell responses. T cells were in CD4 and CD8 compartments, reached up to 4900 interferon γ-producing cells per million peripheral blood mononuclear cells, and primarily pol directed. In contrast, the replication-impaired K65R virus did not induce detectable T-cell responses, likely reflecting the need for adequate replication., Conclusions: Virus-specific T-cell responses occur frequently in oral or topical PrEP-protected pigtail macaques after vaginal exposure to WT SHIV virus. The contribution of such immune responses to protection from infection during and after PrEP warrants further investigation.
- Published
- 2015
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