MDDCs are abundant in lysosomal proteases compared to other DCs.

(A) Immature (i-) and mature (m-) MDDCs are comparable to MΦs in protease protein abundance as assessed by immunoblot of cell lysates. By contrast, immature and mature CD34DCs exhibit remarkably lower expression levels of protease protein than either MΦs or MDDCs. (B) Overexposure of the blots from (A) reveals that the enzymes are present in CD34DCs, though in strikingly diminished amounts. (C) Quantitative RT-PCR shows that MΦs and MDDCs are also distinct in having a high quantity of transcripts for the enzymes compared to CD34DCs. Data are displayed as “fold-greater” than immature CD34DCs. (D) PDCs and MDCs taken ex vivo from healthy donors also display markedly low levels of lysosomal protease expression. γ-tubulin was used as loading control.