Figure 6. Stp1 and Stk1 regulate the host immune response to S. aureus Newman.

(A) Cytokine IL-6 levels were measured in kidney homogenates obtained from infected mice at 5 days post-inoculation. IL-6 levels were significantly lower in kidneys obtained from Δstp1 mutant-infected mice compared to Δstk1 mutant-infected mice (P value = 0.003). (B) Bone marrow derived macrophages (BMMΦ) were stimulated with WT, Δstp1 or Δstk1 S. aureus cells and cytokine IL-6 levels measured as described in the Methods. Secretion of IL-6 was increased in response to S. aureus Δstk1 in comparison to Δstp1 or WT (P value = 0.04). The experiment was repeated three times and similar results obtained. Data shown represent the mean and SD of one experiment.