scholarly journals R5 Human Immunodeficiency Virus Type 1 Infection of Fetal Thymic Organ Culture Induces Cytokine and CCR5 Expression

2005 ◽  
Vol 79 (1) ◽  
pp. 458-471 ◽  
Author(s):  
Shailesh K. Choudhary ◽  
Neelima R. Choudhary ◽  
Katherine C. Kimbrell ◽  
Jonathan Colasanti ◽  
Argyrios Ziogas ◽  
...  

ABSTRACT Late-stage CCR5 tropic human immunodeficiency virus type 1 (HIV-1) isolates (R5 HIV-1) can deplete nearly all CD4+ thymocytes from human thymus/liver grafts, despite the fact that fewer than 5% of these cells express CCR5. To resolve this paradox, we studied the replication and cytopathic effects (CPE) of late-stage R5 HIV-1 biological clones from two progressors and two long-term nonprogressors (LTNP) in fetal thymic organ culture (FTOC) with and without added cytokines. We found that R5 HIV-1 clones from progressors but not LTNP were cytopathic in untreated FTOC. Moreover, R5 HIV-1 clones from progressors replicated to higher levels than LTNP-derived R5 HIV-1 clones in this system. In contrast, when FTOC was maintained in the presence of interleukin 2 (IL-2), IL-4, and IL-7, both progressor and LTNP clones exhibited similar replication and CPE, which were equal to or greater than the levels achieved by progressor-derived R5 HIV-1 clones in untreated FTOC. This finding was likely due to IL-2-induced CCR5 expression on CD4+ thymocytes in FTOC. R5 HIV-1 clones showed greater pathogenesis for CCR5+ cells but also showed evidence of CPE on CCR5− cells. Furthermore, infection of FTOC by R5 HIV-1 induced IL-10 and transforming growth factor β (TGF-β) expression. Both IL-10 and TGF-β in turn induced CCR5 expression in FTOC. Induction of CCR5 expression via cytokine induction by R5 HIV-1 infection of CCR5+ thymocytes likely permitted further viral replication in newly CCR5+ thymocytes. CCR5 expression, therefore, is a key determinant of pathogenesis of R5 HIV-1 in FTOC.

1998 ◽  
Vol 72 (1) ◽  
pp. 830-836 ◽  
Author(s):  
Hassan M. Naif ◽  
Shan Li ◽  
Mohammed Alali ◽  
Andrew Sloane ◽  
Lijun Wu ◽  
...  

ABSTRACT The chemokine receptor CCR5 and to a lesser extent CCR3 and CCR2b have been shown to serve as coreceptors for human immunodeficiency virus type 1 (HIV-1) entry into blood- or tissue-derived macrophages. Therefore, we examined the expression of the chemokine receptors CCR1, CCR2b, CCR3, CCR5, and CXCR4 as RNAs or as membrane-expressed antigens in monocytes maturing into macrophages and correlated these results with the susceptibility of macrophages to HIV-1 infection, as measured by their concentrations of extracellular p24 antigen and levels of intracellular HIV DNA by quantitative PCR. There was little change in levels of CCR1, CCR2b, and CCR5 RNAs. CCR3 RNA and surface antigen were undetectable throughout maturation of adherent monocytes over 10 days. CXCR4 RNA and membrane antigen were strongly expressed in newly adherent monocytes, but their levels declined at day 7. The amounts of CCR5 RNA remained stable, but the amounts of CCR5 antigen increased from undetectable to peak levels at day 7 and then declined slightly at day 10. Levels of susceptibility to laboratory (HIV-1BaL) and clinical strains of HIV-1 showed parallel kinetics, peaking at day 7 and then decreasing at days 10 to 14. The concordance of levels of HIV DNA and p24 antigen suggested that the changes in susceptibility with monocyte maturation were at or immediately after entry and correlated well with CCR5 expression and inversely with CXCR4 expression.


2003 ◽  
Vol 77 (12) ◽  
pp. 6811-6822 ◽  
Author(s):  
Kathryn M. Kitrinos ◽  
Noah G. Hoffman ◽  
Julie A. E. Nelson ◽  
Ronald Swanstrom

ABSTRACT The env gene of human immunodeficiency virus type 1 (HIV-1) includes some of the most genetically diverse regions of the viral genome, which are called variable regions 1 through 5 (V1 through V5). We have developed a heteroduplex tracking assay to detect changes in variable regions 1 and 2 of env (V1/V2-HTA). Using sequences from two molecular clones as probes, we have studied the nature of longitudinal virus population changes in a cohort of HIV-1-infected subjects. Viral sequences present in 21 subjects with late-stage HIV-1 infection were initially screened for stability of the virus population by V1/V2-HTA. The virus populations at entry comprised an average of five coexisting V1/V2 genotypic variants (as identified by HTA). Eight of the 21 subjects were examined in detail because of the dynamic behavior of their env variants over an approximately 9-month period. In each of these cases we detected a single discrete transition of V1/V2 genotypes based on monthly sampling. The major V1/V2 genotypes (those present at >10% abundance) from the eight subjects were cloned and sequenced to define the nature of V1/V2 variability associated with a discrete transition. Based on a comparison of V1/V2 genotypic variants present at entry with the newly emerged variants we categorized the newly emerged variants into two groups: variants without length differences and variants with length differences. Variants without length differences had fewer nucleotide substitutions, with the changes biased to either V1 or V2, suggestive of recent evolutionary events. Variants with length differences included ones with larger numbers of changes that were distributed, suggestive of recall of older genotypes. Most length differences were located in domains where the codon motif AVT (V = A, G, C) had become enriched and fixed. Finally, recombination events were detected in two subjects, one of which resulted in the reassortment of V1 and V2 regions. We suggest that turnover in V1/V2 populations was largely driven by selection on either V1 or V2 and that escape was accomplished either through changes focused in the region under selection or by the appearance of a highly divergent variant.


2002 ◽  
Vol 76 (19) ◽  
pp. 9868-9876 ◽  
Author(s):  
Phalguni Gupta ◽  
Kelly B. Collins ◽  
Deena Ratner ◽  
Simon Watkins ◽  
Gregory J. Naus ◽  
...  

ABSTRACT The virologic and cellular factors that are involved in transmission of human immunodeficiency virus type 1 (HIV-1) across the female genital tissue are poorly understood. We have recently developed a human cervical tissue-derived organ culture model to study heterosexual transmission of HIV-1 that mimics the in vivo situation. Using this model we investigated the role of phenotypic characteristics of HIV-1 and identified the cell types that are first infected during transmission. Our data indicate that the cell-free R5 HIV-1 was more efficiently transmitted than cell-free X4 HIV-1. Cell-free and cell-associated HIV-1 had comparable transmission efficiency regardless of whether the virus was of R5 or X4 type. We have demonstrated that memory CD4+ T cells and not Langerhans cells were the first HIV-1 RNA-positive cells detected at the epithelial-submucosal junction 6 h after virus exposure. Multicolor laser confocal microscopy demonstrated a globular distribution of HIV-1 gag-pol mRNA in the cytoplasm, and the distribution of CD4 and the CD45RO isoform was irregular on the cellular membrane. At 96 h postinoculation, in addition to memory CD4+ T cells, HIV-1 RNA-positive Langerhans cells and macrophages were also detected. The identification of CD4+ T cells in the tissue at 6 h was confirmed by flow cytometric simultaneous immunophenotyping and ultrasensitive fluorescence in situ hybridization assay on immune cells isolated from disaggregated tissue. Furthermore, PMPA {9-[2-(phosphonomethoxy)propyl] adenine}, an antiretroviral compound, and UC781, a microbicide, inhibited HIV-1 transmission across the mucosa, indicating the utility of the organ culture to screen topical microbicides for their ability to block sexual transmission of HIV-1.


1998 ◽  
Vol 72 (11) ◽  
pp. 8952-8960 ◽  
Author(s):  
Lili Huang ◽  
Irene Bosch ◽  
Wolfgang Hofmann ◽  
Joseph Sodroski ◽  
Arthur B. Pardee

ABSTRACT Chemokine receptors CCR5 and CXCR4 are the primary fusion coreceptors utilized for CD4-mediated entry by macrophage (M)- and T-cell line (T)-tropic human immunodeficiency virus type 1 (HIV-1) strains, respectively. Here we demonstrate that HIV-1 Tat protein, a potent viral transactivator shown to be released as a soluble protein by infected cells, differentially induced CXCR4 and CCR5 expression in peripheral blood mononuclear cells. CCR3, a less frequently used coreceptor for certain M-tropic strains, was also induced. CXCR4 was induced on both lymphocytes and monocytes/macrophages, whereas CCR5 and CCR3 were induced on monocytes/macrophages but not on lymphocytes. The pattern of chemokine receptor induction by Tat was distinct from that by phytohemagglutinin. Moreover, Tat-induced CXCR4 and CCR5 expression was dose dependent. Monocytes/macrophages were more susceptible to Tat-mediated induction of CXCR4 and CCR5 than lymphocytes, and CCR5 was more readily induced than CXCR4. The concentrations of Tat effective in inducing CXCR4 and CCR5 expression were within the picomolar range and close to the range of extracellular Tat observed in sera from HIV-1-infected individuals. The induction of CCR5 and CXCR4 expression correlated with Tat-enhanced infectivity of M- and T-tropic viruses, respectively. Taken together, our results define a novel role for Tat in HIV-1 pathogenesis that promotes the infectivity of both M- and T-tropic HIV-1 strains in primary human leukocytes, notably in monocytes/macrophages.


1998 ◽  
Vol 72 (10) ◽  
pp. 8273-8280 ◽  
Author(s):  
James L. Riley ◽  
Bruce L. Levine ◽  
Nancy Craighead ◽  
Tara Francomano ◽  
Daniel Kim ◽  
...  

ABSTRACT In vitro evidence suggests that memory CD4+ cells are preferentially infected by human immunodeficiency virus type 1 (HIV-1), yet studies of HIV-1-infected individuals have failed to detect preferential memory cell depletion. To explore this paradox, we stimulated CD45RA+ CD4+ (naı̈ve) and CD45RO+ CD4+ (memory) cells with antibodies to CD3 and CD28 and infected them with either CCR5-dependent (R5) or CXCR4-dependent (X4) HIV-1 isolates. Naı̈ve CD4+cells supported less X4 HIV replication than their memory counterparts. However, naı̈ve cells were susceptible to R5 viral infection, while memory cells remained resistant to infection and viral replication. As with the unseparated cells, mixing the naı̈ve and memory cells prior to infection resulted in cells resistant to R5 infection and highly susceptible to X4 infection. While both naı̈ve and memory CD4+ subsets downregulated CCR5 expression in response to CD28 costimulation, only the memory cells produced high levels of the β-chemokines RANTES, MIP-1α, and MIP-1β upon stimulation. Neutralization of these β-chemokines rendered memory CD4+ cells highly sensitive to infection with R5 HIV-1 isolates, indicating that downregulation of CCR5 is not sufficient to mediate complete protection from CCR5 strains of HIV-1. These results indicate that susceptibility to R5 HIV-1 isolates is determined not only by the level of CCR5 expression but also by the balance of CCR5 expression and β-chemokine production. Furthermore, our results suggest a model of HIV-1 transmission and pathogenesis in which naı̈ve rather than memory CD4+ T cells serve as the targets for early rounds of HIV-1 replication.


2000 ◽  
Vol 74 (21) ◽  
pp. 10229-10235 ◽  
Author(s):  
Anjali Singh ◽  
Ronald G. Collman

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) variants that use the coreceptor CCR5 for entry (R5; macrophage tropic) predominate in early infection, while variants that use CXCR4 emerge during disease progression. Some late-stage variants use CXCR4 alone (X4; T-cell tropic), while others use both CXCR4 and CCR5 (R5X4; dualtropic). It has been proposed that dualtropic R5X4 strains are intermediates in the evolution from R5 to X4, and we hypothesized that a dualtropic primary-isolate quasispecies might contain variants that represent the spectrum of coreceptor use in vivo. We generated a panel of 35 functional full-length env clones from the primary-isolate quasispecies of a dualtropic prototype strain, HIV-1 89.6PI. Thirty of the functional env clones (86%) were R5X4, four (11%) were R5, and one (3%) was predominantly X4. V3 to V5 sequences did not reveal clustering by coreceptor usage, and no specific sequence motif or V3 charge pattern corresponded to coreceptor utilization. Complete sequencing of seven functionally divergent Env proteins revealed ≥98.7% homology and conservation of structurally important domains. Chimeras between the R5X4 89.6 prototype and an R5 variant indicated that multiple regions contributed to the use of CXCR4, while chimeras with the X4 variant implicated a single residue in V4 in CCR5 use. These results confirm, at the molecular level, both that dualtropic variants are a predominant component of late-stage syncytium-inducing isolates and that variants restricted to each coreceptor coexist with dualtropic species in vivo. Coreceptor-restricted minority variants may reflect residual R5 species from earlier in disease as well as emerging X4 variants.


2005 ◽  
Vol 79 (18) ◽  
pp. 11677-11684 ◽  
Author(s):  
Florian Hladik ◽  
Huanliang Liu ◽  
Emily Speelmon ◽  
Devon Livingston-Rosanoff ◽  
Sean Wilson ◽  
...  

ABSTRACT Exposed seronegative individuals (ES) with persistent high-risk sexual behavior may be less susceptible to human immunodeficiency virus type 1 (HIV-1) infection because they carry the chemokine receptor (CR) gene alleles CCR5 open reading frame (ORF) Δ32, CCR5 promoter −2459G, or CCR2 ORF 64I (CCR2-64I), all of which have been found to diminish HIV-1 infectivity and/or disease progression. To investigate this, we determined the haplotypes for these three genetic loci in 93 ES and 247 low-risk control individuals. To test if protective haplotypes exert their effect by modulating CR expression, we measured the protein expression of CCR5 and CXCR4 on circulating CD4+ T cells and CD14+ monocytes in 71 ES and 92 controls. To avoid investigator bias, the analysis was performed without knowledge of each subject's risk and genotype. The CCR5 −2459G allele was significantly enriched in ES Caucasian men, who constituted the majority (84%) of the ES cohort, compared to the control Caucasian men (P = 0.02). This increase was mostly attributable to a higher frequency of the −2459 A/G versus the −2459 A/A genotype in individuals heterozygous for the Δ32 allele (P = 0.012). No protective influence of the CCR2-64I allele was observed. The haplotypes CCR5 ORF Δ32/CCR5 −2459A (in complete linkage disequilibrium) and CCR5 ORF wt/CCR5 −2459G had a cumulative negative effect on the expression of CCR5, since we measured significantly reduced CCR5 densities on both T-helper cells and monocytes only when both haplotypes were present. Densities of CCR5 on lymphocytes and monocytes were correlated (r = 0.59; P < 0.0001), indicating concordance of CCR5 expression patterns across different cell types. We conclude that the CCR5 ORF Δ32/wt-CCR5 −2459 A/G genotype combination offers an advantage in resisting sexual HIV-1 transmission and that this effect is mediated by a relative paucity of CCR5 on potential target cells of HIV-1.


1998 ◽  
Vol 72 (6) ◽  
pp. 4962-4969 ◽  
Author(s):  
Daniel L. Tuttle ◽  
Jeffrey K. Harrison ◽  
Cynthia Anders ◽  
John W. Sleasman ◽  
Maureen M. Goodenow

ABSTRACT The stage of differentiation and the lineage of CD4+cells profoundly affect their susceptibility to infection by human immunodeficiency virus type 1 (HIV-1). While CD4+ T lymphocytes in patients are readily susceptible to HIV-1 infection, peripheral blood monocytes are relatively resistant during acute or early infection, even though monocytes also express CD4 and viral strains with macrophage (M)-tropic phenotypes predominate. CCR5, the main coreceptor for M-tropic viruses, clearly contributes to the ability of CD4+ T cells to be infected. To determine whether low levels of CCR5 expression account for the block in infection of monocytes, we examined primary monocyte lineage cells during differentiation. Culturing of blood monocytes for 5 days led to an increase in the mean number of CCR5-positive cells from <20% of monocytes to >80% of monocyte-derived macrophages (MDM). Levels of CCR5 expression per monocyte were generally lower than those on MDM, perhaps below a minimum threshold level necessary for efficient infection. Productive infection may be restricted to the small subset of monocytes that express relatively high levels of CCR5. Steady-state CCR5 mRNA levels also increased four- to fivefold during MDM differentiation. Infection of MDM by M-tropic HIV-1JRFLresulted in >10-fold-higher levels of p24, and MDM harbored >30-fold more HIV-1 DNA copies than monocytes. In the presence of the CCR5-specific monoclonal antibody (MAb) 2D7, virus production and cellular levels of HIV-1 DNA were decreased by >80% in MDM, indicating a block in viral entry. There was a direct association between levels of CCR5 and differentiation of monocytes to macrophages. Levels of CCR5 were related to monocyte resistance and macrophage susceptibility to infection because infection by the M-tropic strain HIV-1JRFL could be blocked by MAb 2D7. These results provide direct evidence that CCR5 functions as a coreceptor for HIV-1 infection of primary macrophages.


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