IL-7 as a potential therapy for HIV-1-infected individuals

Highly active antiretroviral therapy (HAART), although effective in amelioratingthe quality of life of HIV-1-infected individuals and their survival, has notbeen able to eradicate HIV-1. In fact, when HAART is interrupted, HIV-1plasma viral load rebounds from viral reservoirs such as resting CD4+T lymphocytes, monocytes and macrophages, remaining a major obstacle inattempting HIV eradication. Different therapeutic strategies have beenattempted, such as structured treatment interruption (STI), immunotherapy(interleukin [IL]-2 and anti-CD3 antibodies [e.g., OKT3]), to try to stimulateHIV-1 out of latency along with antiretroviral intensification therapy. IL-7, apleiotropic cytokine, bears diverse immune properties and plays a major rolein T cell homeostasis. Moreover, IL-7 has recently been investigated as apossible immune adjuvant as well as a viral strain-specific inducer of HIV-1replication. In fact, IL-7 was shown not only to be more effective than IL-2 instimulating HIV-1 replication from resting CD4+ T lymphocytes ex vivo, butalso to selectively induce a specific HIV-1 viral strain as compared with IL-2,suggesting the potential need for different viral inducers if completeeradication is to be achieved. In this present review, different immunologicaland virological properties of IL-7 are discussed, along with the possibility ofits use as part of a combined antiretroviral-immune rationally based HIV-1eradication approach.