HIV-1 gp120 Mannoses Induce Immunosuppressive Responses from Dendritic Cells
Figure 5
Treatment with gp120 Inhibits MDDC-Induced T Cell Proliferation
(A) Day-6 MDDCs were incubated for 48 h with or without TNIL + LPS and/or JR-FL M-gp120, D-gp120, or influenza HA as specified on the x-axis. The MDDCs were then co-cultured for 5 d with CFSE-labeled CD4+ T cells before determination of the extent of the allogeneic mixed T lymphocyte reaction on day 13. Relative CD4+ T cell proliferation was calculated by first subtracting the background value for CFSE-negative cells obtained using unstimulated iMDDCs (9.95% ± 0.70%, n = 15) from the value obtained when the MDDCs were stimulated with TNIL + LPS (46.4% ± 1.54%, n = 15). The net value was defined as 100% and used for normalization. The bars represent the mean values ± SD for data derived from 15 donors (except for influenza HA; ten donors) tested in 15 independent experiments. The superantigen SEB served as a positive control for CD4+ T cell stimulation in the absence of any MDDCs; CFSE dilution in response to SEB was 130% ± 2.9% (n = 15) of that seen with TNIL + LPS (unpublished data).
(B) The extent of T cell proliferation in co-cultures (as in A) containing iMDDCs exposed to M-gp120 + TNIL + LPS + CD40L is plotted as a function of the IL-10 response of the iMDDCs to M-gp120 after 24 h. There was no correlation for iMDDCs from 15 donors (r2 = 0.0008).
(C) In a subset of the experiments shown in (A), extracellular cytokine levels were measured at the end of the MDDC-T cell co-culture (i.e., on day 13). The bars represent the mean values ± SEM from five different donors. Upper panel, IL-10; lower panel, IL-12p70.