Effects of IVIg treatment on DC-mediated T-cell proliferation.

IVIg treatment abrogates the capacity of DCs to stimulate autologous (A-B) and allogeneic (C-D) T cells. Immature DCs obtained by culturing monocytes for 5 days were cultured in the presence of IVIg (0.15 mM) or HSA (0.15 mM) or in the absence of IVIg (Ctl) for an additional 48 hours. Graded doses of DCs were used to stimulate autologous (A) and allogeneic (C) CD4⁺ T cells (1 × 10⁵cells/well) in MLR. In a second type of experiment, immature DCs were treated for 12 hours with IVIg or HSA followed by stimulation with LPS (1 μg/mL) or treated with LPS alone for 48 hours to obtain mature DCs followed by stimulation of autologous (B) and allogeneic (D) T cells. Thymidine incorporation was measured on day 5 by a 16-hour pulse with 1 μCi (0.037 MBq) [³H]thymidine. Results are shown as means ± SDs of triplicate values. Statistical significance as determined by unpaired Student t test (*P < .05; **P < .001) is indicated.