EFFICIENT VIRUS TRANSMISSION FROM DENDRITIC CELLS TO CD4(-CELLS IN RESPONSE TO ANTIGEN DEPENDS ON CLOSE CONTACT THROUGH ADHESION MOLECULES() T)

Monocyte-derived cultured dendritic cells (DCs) are potent antigen-pre senting cells (APCs) and are susceptible to HIV-1(Lai) infection. Comp ared to the low level of virus production by HIV-1-infected DCs alone, a level of virus two to three orders of magnitude higher was produced by cocultivation of HIV-1-infected DCs with autologous resting CD4(+) T cells in the presence of a nominal antigen. In this coculture syste m, direct contact of HIV-1-infected DCs with T cells was crucial for e fficient virus transmission and subsequent virus production. Blocking of the LFA-1/ICAM-1 or LFA-3/CD2 interaction between these cells subst antially reduced virus production, without influence on IL-2 productio n by activated T cells. In contrast, cell-cell transmission of HIV bet ween non-APCs and activated T cells was not blocked by an antibody aga inst LFA-3. Since a low level of virus production by HIV-infected DCs was upregulated by cross-linking of CD40, it was suggested that not on ly focal adhesion, but also mutual activation of HIV-infected DCs and T cells through adhesion molecules, may potentiate virus transmission and production and that such activation signals to HIV may be distinct from signals responsible for IL-2 production in activated T cells. (C ) 1997 Academic Press.