Effects of the oral administration of varying doses of LcZhang on cytokines secretion. Induction of major immunoregulatory cytokines (A: IFN-γ; B: IL-12; C: TNF-α; D: IL-1α) levels in serum by live LcZhang and heat-killed bacteria after 15 days oral administration. Data represent the mean ± standard deviation of each cytokine in pg/ml in serum for each test treatment (n = 10). Three dosages of bacteria were shown: low dose means 0.25 × 109 cells/ml; medium dose means 0.5 × 109 cells/ml; high dose means 1.0 × 109 cells/ml. "Control" refers to the same volume of PBS (open column); "killed" represents heat killed LcZhang (grey column); "live" represents live LcZhang (solid column). Data are means ± S.D. Error bars represent S.D. *P < 0.05; **P < 0.01.