IL15 and bacterial infectious disease: In addition, CXC- chemokines such as CXCL2/MIP-2α, CXCL5/AMCF-II and CXCL8/IL-8 (chemotactic for polymorphonuclear cells), were also expressed at higher levels in BMDCs infected with S. suis. The bacterial infection induced the overexpression of IL-6, TNF-α, IL-1β, IL-15, IL-12p40, and IL-23p19 (the two last being the two subunits of IL-23) (S1 Table).