Because expression of TNFα, IL-6 and IFNγ are essential for control of Listeria infection in mice (Kopf et al., 1994; Unanue, 1997; Williams et al., 2012), and were impaired in Listeria-infected HOIL-1 KO mice (Figure 3C), but elevated in MHV68-infected HOIL-1 KO mice, we considered whether chronic MHV68 infection could complement the profound immunodeficiency observed in Listeria-infected barrier-raised HOIL-1 KO mice. Here, IL6 is linked to immune system disorder.