FIG. 8.
IFN-γ production by spleen cells of IRF-1 KO mice vaccinated with S19, RB51, or the Δpgk mutant strain. IRF-1 KO mice were inoculated with 107 CFU of RB51, 105 CFU of S19, or 105 CFU of Δpgk. Six weeks after vaccination, splenocytes were recovered and stimulated with heat-inactivated B. abortus (HK 2308) or concanavalin A as a positive control. Splenocyte culture supernatants were harvested after 72 h of culture. Bars represent the mean ± standard deviation of quadruplicate sets of cells. Statistically significant differences are indicated by an asterisk (P ≤ 0.05) for the comparison to medium alone and by a number sign (#) for the comparison to the RB51-vaccinated group stimulated with HK 2308.