Coreceptor-Based Hematopoietic Stem Cell Gene Therapy for HIV Disease

Abstract

Combination antiretroviral therapy (cART) has significantly reduced the mortality rate and morbidity, and has increased the life expectancy of the human immunodeficiency virus (HIV) infected patients. However, the current cART is incapable of eradicating viruses from the human body, and HIV remains one of the most notorious viruses mankind has ever faced. HIV-1 enters target cells through the binding of gp120 viral protein to a CD4 receptor and then to a coreceptor, C-C chemokine receptor 5 (CCR5) or C-X-C chemokine receptor type 4 (CXCR4). Individuals homozygous for a 32-bp deletion in the CCR5 allele, CCR5Δ32, are almost completely resistant to HIV-1 acquisition. Moreover, several of natural CXCR4 mutants which have been identified can reduce HIV-1 entry without impairing either ligand binding or signaling. In order to get rid of indefinite treatment for HIV patients, there is a growing interest in creating an HIV-resistant immune system through the use of CCR5 and CXCR4-modified hematopoietic stem cells (HSCs). Proof of concept for this approach has been provided in the instance of "Berlin patient" transplanted with allogeneic stem cells from a donor with homozygosity for the CCR5Δ32 deletion. Here, we review the progress of coreceptor-based HSC gene therapy for HIV disease and present new strategies.