FIG. 4.

Protozoal DNA stimulates the production of IL-12 p40. Macrophages were cultured in serum-free medium with 25 μg of DNA per ml, 50 U of IFN-γ per ml and 10 μg of polymyxin B sulfate per ml. After 24 h, supernatants were collected, serially diluted, and transferred to nitrocellulose membranes by using a dot blot apparatus. The upper blot contains serial dilutions (0.8 to 50 ng) of rHuIL-12. The lower blot contain serial dilutions (1:2 to 1:128) of supernatants from macrophages cultured with the indicated untreated or methylated (M) DNA. IL-12 was detected with bovine IL-12p40-specific MAb and visualized using an alkaline phosphatase conjugate detection system. Autoradiograph films are shown. These data are representative of three experiments.