AEGiS-9CROI: The CCR5 Promoter Polymorphism P1 is Associated with Enhanced Expression of HIV-1 Entry Co-Receptors CCR5, CXCR4, and CCR3 on Primary T Cells

9th Conference on Retroviruses and Opportunistic Infections

Seattle, Washington - February 24 -February 28, 2002

The CCR5 Promoter Polymorphism P1 is Associated with Enhanced Expression of HIV-1 Entry Co-Receptors CCR5, CXCR4, and CCR3 on Primary T Cells

Conf Retroviruses Opportunistic Infect 2002 Feb 24-28;9:abstract no. 30
Carrington M, Perfetto S, Lamoreaux L, Wang C, Larrimore K, Ehrenberg P, Michael N; NCI, NIH, Frederick, MD

BACKGROUND: Subjects homozygous for haplotype P1 in the promoter region of CCR5, a major co-receptor for cellular entry of HIV-1, have previously been shown to progress more rapidly to AIDS. No association between cell surface expression of HIV entry co-receptors on primary CD4⁺ T cells and CCR5 promoter genotype has been established using standard culture techniques with high levels of IL-2 (20 U/mL).

METHODS: We studied the expression of 3 HIV entry co-receptors, CCR5, CXCR4, and CCR3, from 20 HIV-negative subjects with known CCR5 promoter genotype using reduced levels of IL-2. These subjects lacked other host genetic polymorphisms associated with HIV pathogenesis. Fresh PBMC were obtained from subjects with CCR5 genotype P1/P1 (6), P1/P4 (7), and P4/P4 (7). Cells were grown in culture for 14 days in RPMI/10% FCS and 4 U/mL IL-2. Co-receptor cell surface expression was measured on days 0, 7, and 14 using the ABC method for CCR5 and CXCR4 and MCF for CCR3. Chemokine mediated calcium influx was measured by flow cytometry at days 7 and 14 and co-receptor mRNA levels were determined by real-time PCR at time 0 and day 7.

RESULTS: Expression of all 3 co-receptors was 3- to 5-fold higher on both CD4⁺ and CD8+ cells at day 7 from P1/P1 vs P1/P4 and P4/P4 subjects. This correlated with enhanced calcium influx triggered by ligands for CCR5 and CXCR4, but not CCR3, with these cells. No association was observed between CCR5 promoter genotype and coreceptor expression when PBMC from a subset of these patients were cultured with 20 U/mL IL-2. Co-receptor mRNA levels at days 0 and 7 did not associate with CCR5 promoter genotype.

CONCLUSIONS: Subjects homozygous for the CCR5 promoter genotype P1 demonstrate enhanced expression of HIV cellular entry co-receptors on primary T-cells culture with 4 U/mL IL-2 by a post-transcriptional mechanism. Elevated co-receptor expression was associated with increased chemokine receptor function as determined by ligand-induced signaling. These observations provide a functional foundation for more rapid HIV disease progression in P1/P1 subjects.

Keywords: AEGiS, Receptors, HIV, T-Lymphocytes, Receptors, Chemokine, Promoter Regions (Genetics), HIV-1, Polymorphism (Genetics), Antigens, CD4, HIV Infections, Chemokines, AIDS Dementia Complex, Acquired Immunodeficiency Syndrome, Interleukin-2, HIV Seropositivity, Flow Cytometry, Greece, Human, genetics, immunology

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Copyright © 2002 - Foundation for Retrovirology and Human Health. Reproduction of this abstract (other than one copy for personal reference) must be cleared through the Foundation for Retrovirology and Human Health. Licensed (AIDSLINE) from National Library of Medicine.