PERIPHERAL BLOOD-DERIVED CD34(- CXC CHEMOKINE RECEPTOR-4 AND CC-CHEMOKINE RECEPTOR-5 EXPRESSION AND INFECTION BY HIV() PROGENITOR CELLS )

The present study demonstrates cell surface expression of both CXC che mokine receptor 4 (CXCR4) and CC chemokine receptor 5 (CCR5), major co receptors for T cell-tropic and macrophage-tropic strains of HIV, resp ectively, on CD34(+) progenitor cells derived from the peripheral bloo d. CD34+ progenitor cells were susceptible to infection by diverse str ains of HIV, and infection could be sustained for prolonged periods in vitro. HIV entry into CD34(+) progenitor cells could be modulated by soluble CD4, HIV gp120 third variable loop neutralizing mAb and the co gnate ligands for the CXCR4 and CCR5 HIV coreceptors, This study sugge sts that a significant proportion of the circulating progenitor cell p ool may serve as a reservoir for HIV that is capable of trafficking th e virus to diverse anatomic compartments. Furthermore, the infection a nd ultimate destruction of these progenitor cells may explain in part the defective lymphopoiesis in certain HIV-infected individuals despit e effective control of virus replication during highly active antiretr oviral therapy.