FIG 2.

T. gondii, but not other intracellular pathogens, upregulates CD74 protein expression in infected BMMϕ. BMMϕ cultures were infected with T. gondii RH WT tachyzoites (MOI = 2:1), inoculated with heat-killed (HK) parasites (MOI = 10:1), and treated with 200 μg/ml of parasite lysates (A); infected with S. enterica serovar Typhimurium bacteria (MOI = 20:1) (B); or infected with L. donovani promastigotes (MOI = 15:1) (C). After 4 h, the extracellular pathogens were rinsed away, fresh medium was added (antibiotics were resupplemented in wells inoculated with bacteria), and the cells were incubated for 20 h and fixed with 3.7% PFA in PBS. The cells were stained for CD74 (green) and with DAPI. Samples were visualized by epifluorescence microscopy, and the images were deconvolved using AutoQuant X software. CD74 expression levels are shown in uninfected cells (white arrowheads) and infected cells or cells containing phagocytosed parasites (yellow arrowheads). The fields are representative of entire cultures and of the results of three independent experiments. DIC, transmitted-light differential interference contrast.