 In this study, the investigator seeks to understand the immune cells in the cervical fluid of HIV-negative healthy female volunteers, and to see if these cells can be modified using a combined anti-viral and antiinflammatory drug called maraviroc, a medicine used in the treatment of HIV infection. Maraviroc works by preventing HIV from entering human immune cells by blocking a protein on the outside of these cells called the C-C chemokine receptor type 5 CCR5 receptor. When maraviroc is bound to this protein, the virus cannot enter the cell. The investigator thinks that CCR5 antagonists could be particularly good drugs for HIV pre-exposure prophylaxis PrEP and could potentially be dosed in ways that are easier to take than the current drugs used for PrEP. 