Dendritic cells (DC) exposed for a short period of time (1 day) in vitro to HIV infection caused stimulation of autologous T-cells, but those exposed for a longer period (3 days) before addition to T-cells stimulate little or no proliferation [1]. Since a proportion of DC from patients who are HIV-1 seropositive is infected with HIV-1 [2] we used the same culture system to test the level of ongoing stimulation of autologous T-cells by DC. The DC from patients with HIV-1 infection showed no enhanced stimulation of autologous T-cells; they produced significantly lower levels of proliferation than those induced by DC from normal controls or from high risk seronegative individuals. However, DC stimulated production of antibodies to gp120 and p24 in cultures containing autologous B plus T-cell in the absence of any added exogenous antigens as previously described [3]. DC in asymptomatic individuals thus appear to be fuelling antibody production but not T-cell proliferation. The results suggest that a failure by DC to stimulate T-cell proliferation either to HIV-1 or to other environmental antigens may be involved in the failure of cell-mediated responses in HIV infection.