To determine whether infection with HIV-1 strains of different tropisms would influence expression of the mucosa-associated integrins α4β7 and αEβ7 or the lymph node homing receptor L-selectin on peripheral T lymphocytes, cells were infected with the CXCR4-tropic (X4)/syncytium-inducing (SI) HIV-1IIIB strain or with X4/SI or CCR5-tropic (R5)/non-SI (NSI) primary human isolates. Flow cytometric analyses of CD4+ T cells from cultures infected with HIV-1IIIB and one X4/SI primary HIV-1 isolate revealed a significant increase in surface expression of α4β7 and αEβ7 12 days after infection. L-selectin expression was not significantly affected on CD4+ T cells. However, infection with another X4/SI and two R5/NSI primary HIV-1 isolates did not significantly alter homing receptor expression on CD4+ T cells. Since a higher degree of CD4 cytopathicity occurred in those cultures having increased integrin expression, these data suggest that significantly altered mucosal homing receptor expression on CD4+ T cells may result as a "bystander" effect after infection with some cytopathic isolates of HIV-1. © 2001 Academic Press.