FIG. 4.

Overall effect of exogenous recombinant TGF-β (rTGF-β) on endogenous IL-10 production in cell culture supernatants. PBMC culture medium was replaced on day 6 with complete medium containing exogenous rTGF-β (10 ng/ml) or not stimulated with rTGF-β (medium control). Culture supernatants were collected 24 h, 4 days, or 7 days after cytokine stimulation and analyzed by an ELISA. All values were grouped together regardless of time, LPS stimulation, or M. avium subsp. paratuberculosis infection and are presented as the mean concentrations ± standard errors of the means (error bars). The values for the cells not stimulated or stimulated with rTGF-β were statistically significantly different (P < 0.05) as indicated by the different letters over the two groups of bars.