Figure 4.

Evaluation of cytokine secretion by splenocytes from immunized mice, isolated and co-cultured with Ag85B or Rv2351c. The splenocytes were prepared four weeks after the mice were immunized with Ag85B or Rv2351c (three times, 2-week intervals). The splenocytes (1 × 10⁶) were then co-cultured with Ag85B (5 μg/mL) or Rv2351c (5 μg/mL) for 72 h before the levels of the cytokines (A) IFN-γ, (B) IL-2 and (C) IL-4 were measured in the culture supernatants using commercial ELISA kits. The data for cytokine secretion are presented as the mean±SD of two independent experiments. The level of statistical significance for differences between the negative control groups and the Ag85B or Rv2351c groups was determined using the t-test (*P<0.05; **P<0.001).