IL6 and infection: Indeed, increased expression or concentrations of pro-inflammatory cytokines involved in the innate immune response such as IL-1α, IL-1β, IL-6, and TNF-α, have been reported in experimental in vivo or in vitro infections caused by both bacteria like M. haemolytica (7, 11, 33) and M. bovis (34), or viruses as BoHV-1 (7), BRSV (10, 15, 35), and BVDV (23).