ABSTRACT
<p><b>OBJECTIVE</b>To study the effects of HIV Tat protein on CCR5 expression of monocytes and HIV infection in monocytes.</p><p><b>METHODS</b>Membrane expression of CCR5 on monocytes was analyzed by flow cytometry. Stimulated with HIV Tat protein, monocytes were infected with monocyte-tropic HIV(Ba-L) and HIV gag p24 level in the supernatant was measured by ELISA methods.</p><p><b>RESULTS</b>HIV Tat protein increased CCR5 expression in human monocytes,which was inhibited by rabbit anti-Tat polyclonal antibody. Tat protein also increased p24 level after monocyte-tropic HIV-1(Ba-L) infected monocytes.</p><p><b>CONCLUSION</b>Tat increases CCR5 expression and HIV-1 infection in monocytes, which indicates that HIV Tat might be a key protein in HIV-1 infection.</p>