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Abstract
EXPRESSION OF CXCR4 AND SDF-1 IN PERIPHERAL T-CELLS AND LYMPH NODES.
BERMEJO M, MARTIN-SERRANO J, DE PABLOS J, GAMALLO C, ARENZANA F, ALCAMI J
Objectives To analyze the expression and regulation of CXCR4 in resting and activated peripheral blood lymphocytes and the distribution of SDF-1 in lymph nodes.
Methods PBLs were activated with PHA (3ul/ml), soluble OKT3 antibody (1:1000), PMA (25ng/ml), SEA (20ng/ml) or SDF-1 (200 nM). 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 of lymph nodes from HIV infected patients at different clinical stages was analyzed with inmunohistochemistry techniques, using an specific SDF-1 antibody, CD1a and follicular dendritics cells (FDC) antisera.
Results Only about 20% of freshly isolated lymphocytes expressed CXCR4 on the cell surface whereas in 80% of resting blood lymphocytes CXCR4 was located intracellularly. Within a few hours in culture, intracellular CXCR4 was translocated to the membrane and was expressed in the large majority of both naive and memory lymphocytes. A decrease in surface expression of CXCR4 was found when lymphocytes cultured overnight for maximal receptor expression were stimulated with PHA, anti-CD3 antibodies, PMA, SEA or SDF-1. 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. These results suggest that downregulation of CXCR4 in peripheral T-lymphocytes could be related to interaction with SDF-1 in endothelial 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.
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The 1st. IAS Conference on HIV Pathogenesis and Treatment
Abstract no.
73
Suggested Citation
"BERMEJOM, et al.
EXPRESSION OF CXCR4 AND SDF-1 IN PERIPHERAL T-CELLS AND LYMPH NODES..
Oral Presentation:
The 1st. IAS Conference on HIV Pathogenesis and Treatment
:
Abstract no.
73"
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