Effect of IL-10 and IL-12 on long-term survival and differentiation of monocytes. Monocytes (1 × 10⁵/mL) were cultured for 10 days in poly–L-lysine coated plates either in medium alone or in the presence of IL-10 (400 ng/mL) or IL-12 (400 ng/mL) added at the onset of the culture. Monocytes are shown after 1 day (A), 5 days (B), and 10 days (C) of culture. Monocytes were visualized using hematoxilin-eosin coloration (Original magnification × 350). These results are from one representative experiment out of three.