ICAM-3 influences human immunodeficiency virus type 1 replication in CD4(+) T cells independent of DC-SIGN-mediated transmission.

We investigated the role of ICAM-3 in DC-SIGN-mediated human immunodeficiency virus (HIV) infection of CD4(+) T cells. Our results demonstrate that ICAM-3 does not appear to play a role in DC-SIGN-mediated infection of CD4(+) T cells as virus is transmitted equally to ICAM-3(+) or ICAM-3(-) Jurkat T cells. However, HIV-1 replication is enhanced in ICAM-3(-) cells, suggesting that ICAM-3 may limit HIV-1 replication. Similar results were obtained when SIV replication was examined in ICAM-3(+) and ICAM-3(-) CEMx174 cells. Furthermore, while ICAM-3 has been proposed to play a co-stimulatory role in T cell activation, DC-SIGN expression on antigen presenting cells did not enhance antigen-dependent activation of T cells. Together, these data indicate that while ICAM-3 may influence HIV-1 replication, it does so independent of DC-SIGN-mediated virus transmission or activation of CD4(+) T cells.