Human Follicular Dendritic Cells Remain Uninfected and Capture Human Immunodeficiency Virus Type 1 through CD54-CD11a Interaction

It has been reported that human immunodeficiency virus type 1 (HIV-1) bound to follicular dendritic cells (FDCs) remains highly infectious to CD4(+) T cells even when it forms immune complexes with neutralizing antibody (HIV-1/IC). To elucidate the role of FDCs in HIV-1 transmission to CD4(+) T cells in lymph nodes, we have isolated and purified FDCs from human tonsils and examined whether the HIV-1/IC trapped on their surface is infectious to CD4(+) T cells. To our surprise, not the HIV-1/IC but the antibody-free HIV-1 on FDCs could be transmitted to CD4(+) T cells. Furthermore, in contrast to previous studies showing that FDCs are productively infected with HIV-1, the present study clearly demonstrated that FDCs were not the target cells for HIV-1 infection. FDCs could capture the viral particles on their surface; however, the binding of HIV-1 to FDCs was strongly inhibited by the presence of anti-CD54 (ICAM-1) monoclonal antibody (MAb) and anti-CD11a (LFA-1) MAb, suggesting that the adhesion molecules play an important role in the interaction between HIV-1 and FDCs.