Interleukin 10, also known as cytokine synthesis inhibitory factor (CSIF), is the charter member of the IL10 family of alpha helical cytokines that also includes IL19, IL20, IL22, IL24, and IL26/AK155. Mature human IL10 shares 72%-86% amino acid sequence identity with bovine, canine, equine, feline, mouse, ovine, porcine, and rat IL10. Whereas human IL10 is active on mouse cells, mouse IL10 does not act on human cells. IL10 is a critical molecule in the control of viral infections and allergic and autoimmune inflammation. It promotes phagocytic uptake and Th2 responses but suppresses antigen presentation and Th1 proinflammatory responses. The activity of IL10 is usually measured by a cell proliferation assay using MC/9 mouse mast cells. MC/9 cells were seeded into triplicate wells of 96-well plates at a density of 8,000 cells/well with 2% serum standard DMEM which contains various concentrations of recombinant chicken IL4. After incubated for 3 days, cells were observed by inverted microscope and cell proliferation was measured by Cell Counting Kit-8 (CCK-8). Briefly, 10 µl of CCK-8 solution was added to each well of the plate, then the absorbance at 450 nm was measured using a microplate reader after incubating the plate for 2-4 hours at 37 ℃. Proliferation of MC/9 cells after incubation with IL10 for 3 days observed by inverted microscope was shown in Figure 1. Cell viability was assessed by CCK-8 (Cell Counting Kit-8 ) assay after incubation with recombinant chicken IL10 for 3 days.
The result was shown in Figure 2. It was obvious that IL10 significantly increased cell viability of MC/9 cells. The ED50 is 0.92 -9.2 ng/ml.

Figure 2. Cell proliferation of MC/9 cells after stimulated with IL10.