IFN-α/β does not alter phagocytosis or phenotypic or functional maturation of DCs. (A) Phagocytosis of PKH26 (red dye)–labeled apoptotic cells by PKH67 (green dye)–labeled iDCs was monitored by flow cytometry. iDCs and apoptotic T cells were distinguished based on forward scatter (FSC) and side scatter (SSC) properties, as shown. Gating on iDCs using scatter and FL-1 criteria permitted monitoring of cells that engulfed a red-labeled dying cell, as based on their becoming double positive (lower FACS plots). Cocultures were incubated in the presence of media, EDTA, or IFN-α as indicated. Percent phagocytosis is indicated. (B) FACS analysis of CD83, CD86, HLA-DR, and CD40 expression levels on iDCs, mDCs, or DCs matured in the presence of IFN-α/β (IFN-DC). (C) Allostimulatory potential of mDCs or DCs matured in the presence of IFN-α/β (IFN-DC) was monitored by stimulation of T-cell proliferation after 5 days of culture. Proliferation was monitored by incorporation of 3H-thymidine. Triplicate wells are averaged and SEM is represented by error bars.
