Figure 3
Cellular immune responses. A The IFNɣ titers of different groups on days 14, 21, 28, and 38. The serum samples were diluted 1:10 before the ELISA assay. B The p values for pairwise comparisons between different groups for IFNγ titers. C Percentage of spleen cell proliferation in different groups on days 21, 28, and 38. Chickens were immunized with BGs through inhalation (Inhal. BGs + Expo.), BGs by injection (Inj. BGs + Expo.), and injection of killed vaccine (Killed + Expo.) on days 7, 14, 21, and were challenged on day 28 with the wild type E. coli O78:K80. Chickens in the only exposure (only Expo.) group without immunization were challenged. Chickens in the negative control (Neg. Ctrl.) group neither received any immunization nor challenged. Data represent the OD450 nm of at least three to five chicken samples in triplicate for IFNγ titers and three or four spleen chicken for cell proliferation assay in triplicate. Data in B were normalized with the corresponding data in the Neg. Ctrl. group. Data were normalized with the Neg. Ctrl. group in each time points. The bold font in B represents the statistically significant p values (p < 0.05).