Accumulation of IPCs in inflamed lymph nodes. (A) Heat-killed Mtb does not trigger secretion of IFN-α by IPCs in vitro. Bone marrow-derived IPCs were incubated with varying concentrations of heat-killed Mtb and IFN-α response was measured by ELISA. Controls include stimulation with HSV-1 (1 MOI), CpG ODN 2216 (3 μg/mL), and no stimulation. (B) 440c⁺/CD11c⁺ IPCs in lymph nodes draining either the site of inflammation (right plot) or the controlateral site (left plot). The percent of IPCs is indicated. Equal numbers of events are shown in each plot. (C-D) IPCs in histologic sections of lymph nodes draining either the site of inflammation (C) or the controlateral site (D). 129/SvJ mice were inoculated with heat-killed Mtb in the left hind leg and footpad twice at a 48-hour interval. At 72 hours, inguinal and popliteal lymph nodes were separately harvested from the left and right sides of the mouse. Total cell populations were stained with 440c and CD11c (original magnification, × 10). Lymph node sections were analyzed by immunohistochemistry.