Abstract
HIV-1 entry requires the cell surface expression of CD4 and either the CCR5 or CXCR4 coreceptors on host cells. Individuals homozygous for the ccr5Δ32 polymorphism do not express CCR5 and are protected from infection by CCR5-tropic (R5) virus strains. As an approach to inactivating CCR5, we introduced CCR5-specific zinc-finger nucleases into human CD4+ T cells prior to adoptive transfer, but the need to protect cells from virus strains that use CXCR4 (X4) in place of or in addition to CCR5 (R5X4) remains. Here we describe engineering a pair of zinc finger nucleases that, when introduced into human T cells, efficiently disrupt cxcr4 by cleavage and error-prone non-homologous DNA end-joining. The resulting cells proliferated normally and were resistant to infection by X4-tropic HIV-1 strains. CXCR4 could also be inactivated in ccr5Δ32 CD4+ T cells, and we show that such cells were resistant to all strains of HIV-1 tested. Loss of CXCR4 also provided protection from X4 HIV-1 in a humanized mouse model, though this protection was lost over time due to the emergence of R5-tropic viral mutants. These data suggest that CXCR4-specific ZFNs may prove useful in establishing resistance to CXCR4-tropic HIV for autologous transplant in HIV-infected individuals.
Highlights
For HIV to infect cells, the viral envelope (Env) protein must bind to the host protein CD4 and to a coreceptor, most commonly CCR5 (R5 HIV)
For HIV to enter T cells, the virus first binds to a primary surface receptor CD4 and to a coreceptor, either CCR5 or CXCR4
We report the use of novel zinc-finger nucleases that and permanently disrupt the CXCR4 gene in T cells
Summary
For HIV to infect cells, the viral envelope (Env) protein must bind to the host protein CD4 and to a coreceptor, most commonly CCR5 (R5 HIV) (reviewed in [1]). An HIV infected patient with acute myelogenous leukemia received a bone marrow transplant from a ccr5D32 homozygous donor [6]. This patient’s viral load remains undetectable even in the absence of anti-retroviral therapy more than three years post-transplant, suggesting that this individual’s HIV infection has been eradicated. Virus strains that can utilize CXCR4 either in place of (X4 HIV) or in addition to CCR5 (R5X4 HIV) are found at significant levels in roughly 50% of late-stage infected individuals [7,8], supporting the need for therapies targeted to CXCR4 [9]. If approaches could be developed that target expression of both CCR5 and CXCR4 on CD4+ T cells, virus entry should be inhibited more effectively
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
