Higher Infectivity of the Human Immunodeficiency Virus in Sensitive Cells with a Modification of the CCR5 Gene

As a natural mutation of the human ccr5 gene has been shown to confer resistance to human immunodeficiency virus type 1 (HIV-1) infection, a new avenue has opened in the development of alternative treatment approaches through genome editing. One of the two chemokine co-receptors of the plasma membrane is utilized by HIV-1 to infect CD4⁺ cells. HIV-1 strains that utilize CCR5 circulate in early infection, and strains that utilize CXCR4 circulate at advanced stages. A complex relationship may exist in the expression regulation of the receptors and may affect virus replication in cells that normally do not express CCR5 on the membrane, such as the MT-4 cell line. MT-4 cells were used to study the effect of ccr5 modification HIV-1 replication in vitro. Genetic modification of ccr5 in MT-4 cells was shown to increase the activities of HIV-1 strains, especially in homozygote. The results indicate that genome editing should be performed with caution in human cells and that the issue needs comprehensive investigation.