In a study of cytokine expression, following infection with wild type C. pseudotuberculosis it was found that at the site of inoculation, the inflammatory cytokines TNF-α and IL1-β were up regulated on day 7 p.i., whereas on day 28 p.i IL1-β and IL-6 showed increased expression while the expression of TNF-α had returned to baseline. This evidence concerns the gene TNF and infection.