FIG. 3.

Effects of exogenous cytokines on the bactericidal activity of unfractionated PBMC cultures from healthy noninfected cows (n = 5). After 6 days, PBMC culture supernatants were replaced with fresh medium containing recombinant IFN-γ (100 ng/ml), recombinant IL-10 (rIL-10) (100 ng/ml), rTGF-β (10 ng/ml), and rIL-10 (100 ng/ml) plus rTGF-β (10 ng/ml). The medium control was not stimulated with a cytokine. Eighteen hours later, cultures were infected with live M. avium subsp. paratuberculosis (10:1 bacterium-to-adherent cell ratio). Data shown are the numbers of viable bacteria (mean numbers of CFU ± standard errors of the means [error bars]) recovered from cell culture lysates and supernatants 6 days after in vitro infection with M. avium subsp. paratuberculosis. The values for cytokine treatment groups were statistically significantly different (P < 0.05) (values with the same letter were not significantly different). 1.E+05, 1 × 10⁵.