Since its formation, Retroviral Diseases Section has conducted research on human immunodeficiency virus (HIV) disease, in addition to our studies on HIV-associated malignancies. The studies on HIV have for a number of years focused on the HIV protease and the GagPol protease precursor. During the past year, we have been collaborating with Dr. Mitsuya's group on studies of the entry of novel HIV protease inhibitors into the brain, using an in vitro system. We have also been collaborating on the development of novel HIV protease inhibitors that are more potent than available drugs and active in HIV resistant to current drugs. We have also been conducting a trial of the anti-PD-L1 drug pembrolizumab an d as part of this studying its effect on the HIV reservoir. In addition, in a new collaboration with Dr. Marjorie Robert-Guroff in NCI, we have been developing a novel technique to sort HIV virions using flow cytometry. Finally, in collaboration with Drs. Maldarelli and Hughes in NCI, we have been studying the oligoclonal nature of HIV integration in patients on long-term anti-HIV therapy. Finally, we are assessing means of enhancing expression of MHC-1 and other ligands involved in immune recognition on HIV-infected cells.