PrEP, Lube, and the Rectal Mucosa in MSM at Risk of HIV

Inclusion Criteria: * HIV-negative man who reports receptive anal sex with another man in the last 6 months aged 18-49 years * Male to female transgender women who are not currently taking hormonal therapy or plan to take hormonal therapy for the duration of the study * Not currently taking pre-exposure prophylaxis (PrEP) and no plans to initiate during study * Able to provide informed consent in English * No plans for relocation in the next 6 months * Willing to undergo peripheral blood and rectal biopsy sampling * Willing to use study products as directed * Willing to abstain from receptive anal intercourse 3 days prior to study visit 2 (4-16 weeks after the screening visit)and 10 days prior to study visit 4 (5-26 weeks after the screening visit) * Willing to abstain from receptive anal intercourse for 1 week after study visit 2 (4-16 weeks after the screening visit) and study visit 4 (5-26 weeks after the screening visit) Exclusion Criteria: * History of inflammatory bowel disease or other inflammatory, infiltrative, infectious or vascular condition involving the lower gastrointestinal tract that, in the judgment of the investigators, may be worsened by study procedures or may significantly distort the anatomy of the distal large bowel * Significant laboratory abnormalities at baseline visit for rectal biopsies, including but not limited to: 1. Hemoglobin (Hbg) ≤ 10 g/dL 2. Partial thromboplastin time (PTT) \> 1.5x upper limit normal (ULN) or international normalized ratio (INR) \> 1.5x ULN 3. Platelet count \<100,000 * Any known medical condition that, in the judgment of the investigators, increases the risk of local or systemic complications of endoscopic procedures or pelvic examination, including but not limited to: 1. Uncontrolled or severe cardiac arrhythmia 2. Recent major abdominal, cardiothoracic, or neurological surgery 3. History of uncontrolled bleeding diathesis 4. History of colonic, rectal, or vaginal perforation, fistula, or malignancy 5. History or evidence on clinical examination of ulcerative, suppurative, or proliferative lesions of the anorectal or vaginal mucosa, or untreated sexually transmitted disease with mucosal involvement * Continued need for, or use during the 14 days prior to enrollment, of the following medications: 1. Aspirin or more than 4 doses of nonsteroidal anti-inflammatory drugs (NSAIDs) 2. Warfarin, heparin (low-molecular weight or unfractionated), platelet aggregation inhibitors, or fibrinolytic agents 3. Any form of rectally administered agent besides products lubricants or douching used for sexual intercourse * Continued need for, or use during the 90 days prior to enrollment, of the following medications: 1. Systemic immunomodulatory agents 2. Supraphysiologic doses of steroids 3. Experimental medications, vaccines, or biologicals * Intent to use HIV antiretroviral PrEP during the study, outside of the study procedures * Symptoms of an untreated rectal sexually transmitted infection (e.g. rectal pain, discharge, bleeding, etc.) * Current use of hormonal therapy * Any other clinical condition or prior therapy that, in the opinion of the investigator, would make the patient unsuitable for the study or unable to comply with the study requirements