Considering the importance of IFN-γ in the bacterial clearance and that ST2 deficiency enhances IFN-γ+CD4+T cells skewing and IFN-γ-dependent killing activity of BMDM, it was then investigated whether mice lacking IFN-γ presented impaired response in septic arthritis and whether this was related to IL-33 production. The gene discussed is IFNG; the disease is bacterial arthritis.