HMGB1 and infection: As was shown in Figure 6a, WT and ΔYopM/YopM-infected mice displayed significantly increased serum HMGB1 levels as compared with the ΔYopM and ΔYopM/YopM C68A-infected mice with the infection time progressed (Figure 6a), while serum IL-1β levels were not markedly elevated in WT, ΔYopM/YopM, and ΔYopM/YopM C68A-infected mice (Figure 6b).