Fig. 3.

Interleukin (IL)-21 enhances macrophage (MΦ) phagocytosis, protease activity and MMP12 expression. (a) IL-21 significantly stimulates MΦ phagocytosis of fluorescein isothiocyanate (FITC)–dextran, which was more pronounced in IL-21MΦ. MFI: mean fluorescence index. In addition, original fluorescence activated cell sorter data from one representative experiment are shown; the upper row shows FITC–dextran in medium, the lower row shows FITC–dextran with IL-21 added for the 30-min incubation period. Numbers in the blots give the MFI. (b) In accordance with high antigen-uptake, IL-21MΦ display significantly higher unspecific protease activity after lipopolysaccharide activation. RFU: relative fluorescence units. (c) Reverse transcription–polymerase chain reaction showed message induction for MMP12 by short-term IL-21 incubation and higher baseline expression in IL-21MΦ.