In previous studies evaluating the S. suis-dependent cytokine production, IL1β, along with other key inflammatory cytokines, such as IL6 and IL8, was found to be produced by porcine monocytes and polymorphonuclear lymphocytes in a whole-blood system in response to infection, as well as in human THP-1 monocytes (Segura et al., 2002; Segura et al., 2006). This evidence concerns the gene IL6 and infection.