Cell surface CCR5 density determines the postentry efficiency of R5 HIV-1 infection

Abstract

We have recently reported that the mean number of CCR5 coreceptors at the surface of CD4 ؉ T cells (CCR5 density) correlates with viral load and disease progression in HIV-1-infected persons. Here, we definitively establish that CCR5 density determines the level of virus production and identify the stages of HIV-1 replicative cycle modulated by this effect. We show, by transducing the CCR5 gene into CCR5 ؉ cells, that CCR5 overexpression resulted in an HIV-1 overinfectability. We sorted HOS-CD4 ؉ -CCR5 ؉ cells into two subpopulations, HOS high and HOS low , the former expressing seven times more cell surface CCR5 molecules than the latter. Virus production was 30 -80 times higher in HOS high cells than in HOS low cells after a single round of infection. In contrast, only twice as many viral particles entered the cytosol of HOS high cells as compared with the cytosol of HOS low cells. Yet, seven times as many early, and 24 times as many late, reverse transcription products were found in HOS high cells as compared with HOS low cells. Moreover, a 24-to 30-fold difference in the number of copies of integrated HIV-1 DNA was observed. No difference in HIV-1 LTR activation between the two cell lines was evident. Finally, we show that the higher virus production observed in HOS high cells is inhibited by pertussis toxin, a G␣i protein inhibitor. Thus, CCR5 density mainly modulates postentry steps of the virus life cycle, particularly the reverse transcription. These data explain why CCR5 density influences HIV-1 disease progression and underline the therapeutic interest of lowering CCR5 expression.coreceptor ͉ chemokine ͉ activation ͉ retrovirus life cycle ͉ AIDS T here is a large interindividual variability in viral load among HIV-1-infected persons. As HIV RNA plasma level is a major predictive indicator of bioclinical outcome (1), it is important to identify the host factors responsible for this variability. The C-C chemokine receptor CCR5 plays a key role during HIV-1 infection. It is used in addition to CD4 as a coreceptor by HIV-1 strains isolated from the blood of infected persons from the beginning of the infection at least until AIDS develops (2). The importance of CCR5 in the physiopathology of HIV-1 infection is illustrated by the effect of a 32-bp deletion in the CCR5 gene, resulting in a mutant gene, ⌬32CCR5, encoding a truncated CCR5 molecule that is not expressed at the cell surface. Homozygotes for this ⌬32 deletion are usually resistant to the infection, and heterozygotes progress slowly in the infection (3, 4). We have recently shown that one of the factors determining the level of viral load in HIV-1-infected persons is the density of CCR5 coreceptors at the single CD4 ϩ T cell level (5). Thus, persons exhibiting high CCR5 expression exhibit high viral loads and persons exhibiting low CCR5 expression exhibit low viral loads. Interestingly, the correlation between CCR5 expression and viremia is logarithmic, a small difference in CCR5 density resulting in a marked difference in HIV RNA plasma levels. As...

A haplotype of the human CXCR1 gene protective against rapid disease progression in HIV-1+patients

“…CCR5 delta-32 gives rise to a truncated CCR5 molecule that forms heterocomplexes with intact CCR5 in the endoplasmic reticulum, leading to reduced CCR5 cell-surface density and contributing to slower disease progression in heterozygotes (8-10). The major effect of the reduced CCR5 density appears to be modulation of virus replication cycle in early stages, particularly of reverse transcription (24).…”

Oncolytic activities of approved mumps and measles vaccines for therapy of ovarian cancer

“…8,25 We and others have demonstrated that receptor number is an important determinant of virus infectivity or vector transduction efficiency of target cells. [26][27][28][29] Indeed, one of the major hindrances to effective gene delivery by type 5 adenovirus (Ad5) is poor transduction efficiency due to low expression levels of the coxsackieadenovirus receptor (CAR) on cancer cells. 29 Strategies to enhance Ad5 gene transfer include modifying and retargeting the knob proteins of the virus.…”

Combined Effect of CCR5-Δ32 Heterozygosity and the CCR5 Promoter Polymorphism −2459 A/G on CCR5 Expression and Resistance to Human Immunodeficiency Virus Type 1 Transmission

“…Peripheral CD4 ؉ T lymphoblasts from ORF ⌬32/wt plus ؊2459 A/G individuals do not exhibit increased resistance to direct in vitro infection. We postulated that the lower expression levels of CCR5 observed in CCR5 ORF ⌬32/wt plus Ϫ2459 A/G individuals decreased the susceptibility of target cells to infection with R5-tropic HIV-1 strains (1,18,24,44,48). To screen for this effect, we infected PHA-stimulated CD4 ϩ T lymphoblasts from 77 ES and 25 control individuals with HIV-1 JR-CSF and stratified infectivity levels by CCR5 ORF plus Ϫ2459 genotype combinations.…”