Influenza virus upregulates CXCR4 expression in CD4(+) cells

We examined the effect of prior influenza virus infection on the susceptibi lity of CD4(+) cells to HIV-1 infection. Influenza virus infection of HeLa- CD4 cells resulted in a marked increase in susceptibility to infection by C XCR4-dependent but not CCR5-dependent HIV isolates. Influenza virus infecti on resulted in an increase in the steady state level of CXCR4 transcripts a nd an increase in cell surface CXCR4 expression. Our observations suggest t hat infectious agents such as influenza may contribute to HIV disease progr ession by modulating coreceptor availability.