FIG. 5.

Protozoal DNA induces IL-12-like activity. Macrophages were cultured for 24 h with 25 μg of bovine DNA (negative control), E. coli DNA (positive control), or untreated or methylated B. bovis or T. brucei DNA per ml, IFN-γ, and polymyxin B sulfate. Supernatants were assayed by ELISA for induction of IFN-γ by PHA-costimulated PBMC. Results are presented as the mean and 1 SD of duplicate determinations and are representative of two experiments. Significantly more IFN-γ was induced by T. brucei and B. bovis DNA than by bovine DNA or the corresponding methylated DNA (P < 0.01, indicated by asterisk).