AEGiS-9CROI: Expression of CXCR4 and SDF-1 in Lymphocytes and Dendritic Cells

9th Conference on Retroviruses and Opportunistic Infections


Seattle, Washington - February 24 -February 28, 2002

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Expression of CXCR4 and SDF-1 in Lymphocytes and Dendritic Cells

Conf Retroviruses Opportunistic Infect 2002 Feb 24-28;9:abstract no. 256-T
Bermejo M, Martin-Serrano J, de Pablos JL, Alonso JM, Gamallo C, Arenzana-Seisdedos F, Alcami J; Inst. de Salud Carlos III, Majadahonda, Spain

BACKGROUND: Our objective was to analyze the expression and regulation of CXCR4 in resting and activated peripheral blood lymphocytes and the expression of SDF-1 in lymph nodes and cultured dendritic cells.

METHODS: PBLs were activated with PHA, soluble OKT3 antibody, PMA, SEA, or SDF-1. Membrane and cytosolic CXCR4 expression was measured at different times using flow cytometry and confocal laser scanning microscopy. Characterization of SDF-1-producing cells in paraffin-embedded sections in normal tonsils and of lymph nodes from HIV-infected patients at different clinical stages was analyzed with inmunohistochemistry and in situ hybridization techniques, using specific antibodies against SDF-1, CD1a and dendritic cells antigens. Expression of SDF-1 was assessed in an in vitro model of dendritic cell differentiation, using flow cytometry and western blot techniques.

RESULTS: Only about 20% of freshly isolated lymphocytes expressed CXCR4 on the cell surface whereas in 80% of resting lymphocytes CXCR4 was located intracellularly. Neither resting nor activated T-cells produced SDF-1. In contrast, SDF-1 was widely expressed in endothelial cells and also in dendritic cells (CD1a+) in the parafollicular compartment of lymph nodes.

CONCLUSIONS: These results suggest that downregulation of CXCR4 in peripheral T-lymphocytes could be related to interaction with SDF-1 in endothelial and dendritic cells. The presence of SDF-1 producing cells in the parafollicular T-cell region could account for the low propagation of X4 HIV strains in early stages of infection, in which lymph node structure is still conserved.

Keywords: AEGiS, Chemokines, CXC, Dendritic Cells, T-Lymphocytes, HIV Infections, Phytohemagglutinins, Down-Regulation, Lymph Nodes, Flow Cytometry, Anti-HIV Agents, Cells, Cultured, HIV Seropositivity, Blotting, Western, Oceans and Seas, stromal cell-derived factor-1alpha, In Vitro, Human, genetics

020224
256-T

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.