Bovine PBMC subsets co-expressing CD77 after in vitro challenge with recombinant Shiga toxins and toxoids. Proportions of bovine PBMC and of PBMC subsets co-expressing CD77 in PHA-P stimulated cultures are shown relative to data obtained from PHA-P stimulated cultures incubated in the presence of the vector control (control cultures; defined as 1.0, indicated by the dashed line). Data is depicted as means ± standard deviations of 3 to 6 repetitive experiments as indicated. Statistical analysis was performed as described in legend to Figure 2. Significance levels were defined as p ≤ 0.001 [***], p ≤ 0.01 [**], and p ≤ 0.05 [*].