Introduction The two most commonly used nucleos(t)ide reverse transcriptase inhibitors (NRTIs), tenofovir (TFV) and emtricitabine (FTC), in antiretroviral (ARV) therapy (ART) for HIV-infection in humans are also the ones, but only in combination with one another, approved for daily use as pre-exposure prophylaxis (PrEP) of HIV prevention strategy. In HIV-infection in humans and SIV-infection of rhesus macaques (RMs), lymphoid tissues are a major site of viral production and storage (1).