Fig. 4: Early cellular responses in vaccine groups following challenge with a wild type strain of M. paratuberculosis.

Six to eight week-old C57BL/6 mice were immunized with various vaccine candidates. At 6 WPV they were challenged with M. paratuberculosis JTC-1285 and euthanized 12 weeks later (12 WPC). The lymphocytes were isolated from the spleens and stimulated with whole cell lysate of M. paratuberculosis for 24 h. Cells were then stained for CD4⁺ (a) and CD8⁺ (b) cell surface markers and intracellular cytokines and were measured by flow cytometry. The total percentage of T cells secreting particular cytokines are indicated below each pie chart (denoted by T = number). The error bars show the standard error of the mean for five individually analyzed mice. * indicates p < 0.05; ** indicates p < 0.001. * denotes comparison with PBS while ^# denotes comparison with Mycopar®. Results were expressed as the increase in the percentage of the cells with positive staining relative to that of an unstimulated sample stained with the same antibody.