Distribution of the human immunodeficiency virus coreceptors CXCR4 and CCR5 in fetal lymphoid organs: Implications for pathogenesis in utero

HIV entry into a cell requires the coordinate cell surface expression of CD 4 and one of several chemokine coreceptors, Here we have examined the expre ssion of the two most widely utilized HIV coreceptors, CXCR4 and CCR5, on v arious lymphoid tissues derived from the fetus. CXCR4 and CCR5 are differen tially expressed on lymphocytes in different lymphoid organs, which may ref lect the maturational and functional status of cells within the organ. The different levels of coreceptor expression on CD4(+) cells in the various or gans may directly affect the targeting of CXCR4- and CCR5-tropic strains of HIV toward different fetal lymphoid tissues during in utero infection.