CD8+ cytotoxic T lymphocytes (CTLs) play a key role protective role in the immunopathogenesis of HIV-1 infection, but eventually fail in most persons due to lagging behind the virus. Numerous data indicate that HIV- 1-specific CTLs mediate the suppression of HIV-1 that mediates the ?asymptomatic phase? of chronic infection. The CTL response arises by clonal expansion from the nave cell population, and once the antigen is cleared to low or absent levels, most of these cells die, leaving resting central memory cells with low effector function, but which are primed for more rapid expansion upon re-challenge to effector cells. This process results in the lag of CTLs behind HIV-1, and viral sequence evolution outpaces CTLs to allow mutational escape during established infection that is likely a major mechanism of viral persistence leading to CTL exhaustion and eventual failure. Although treatment with antiretroviral therapy (ART) stops most ongoing viral replication and could potentially allow immune regeneration that could control infection after treatment interruption, CTL responses to decay to resting memory levels, and treatment interruption usually leads to a rapid rise in viremia similar to acute infection. We hypothesize that continuously driving persistence of effector CTLs against HIV-1 could interrupt this pathogenic cycle. Rather than allowing CTLs to lag behind HIV-1, we propose a strategy to maintain levels of HIV-1-specific effector CTLs independently of HIV-1 replication. This could prevent (in the case of an uninfected person) or break (in the case of an infected person on ART) the pathogenic cycle leading to CTL dysfunction. To achieve this goal, we will take advantage of the in vivo chronic antigenic stimulus of human cytomegalovirus (CMV) to drive CTLs that recognize both CMV and HIV-1. Specifically, we aim: 1. To engineer lentiviral vectors that generate CAR T cells targeting CMV and HIV-1 simultaneously; 2. To confirm the function of these vectors in vitro as a prerequisite for future animal studies.
/RELEVANCE TO PUBLIC HEALTH With chimeric antigen receptor gene therapy for cancer being a growing area of therapeutic promise, there is great potential for application to HIV treatment. This project addresses a cellular immune defect specific to HIV that could enhance the utility of CARs for the functional cure of HIV infection.
