Norovirus gastroenteritis is a major public health burden worldwide. tract.

Norovirus gastroenteritis is a major public health burden worldwide. tract. Human being noroviruses (HNoVs) are a leading cause of gastroenteritis worldwide (1 2 Asymptomatic fecal dropping of HNoVs may be important epidemiologically by providing a reservoir between outbreaks (1 3 Some strains of murine norovirus (MNoV) also set up prolonged enteric infection providing a model for analyzing mechanisms of enteric NoV persistence and immunity in a natural sponsor (1 10 11 Interferons (IFNs) are critical for control of both murine and human NoV replication (12-18). IFN-α and IFN-β (also called Type I IFNs and hereafter IFN-αβ) IFN-γ (also called Type II IFN) and IFN-λ (also called Type III IFN or interleukin 28/9) signal through the distinct heterodimeric receptors Ifnar1/Ifnar2 Ifngr1/Ifngr2 and Ifnlr1/Il10rb to regulate gene expression through phosphorylation of Stat proteins (19 20 Although the roles of IFNs in control of persistent enteric infection have not been elucidated it is of interest that IFN-λ but not IFN-αβ is usually important for control of acute rotavirus contamination in the intestine of mice (21). To define the role of IFNs in MNoV enteric persistence we measured levels of the persistent MNoV strain CR6 in different tissues and in feces after oral inoculation of control mice and mice deficient in or (Fig. 1) (also see supplementary materials and methods). As expected and were important for limiting replication in the spleen and mesenteric lymph node (MLN) (12 B-HT 920 2HCl 13 16 17 whereas rather than controlled levels of replication in the colon (Fig. 1A) suggesting that IFN-αβ responses did not explain Stat1-dependent control of replication in the intestine. Consistent with this comparison of the requirement for each IFN receptor in control of fecal shedding revealed that only and limited levels of fecal shedding of MNoV (Fig. 1B). Furthermore we observed increased fecal shedding compared to controls in but B-HT 920 2HCl not (fig. S2). The capacity of strain CW3 to infect systemic organs maps to the protruding domain name of the viral capsid protein (11 22 whereas a single coding change (Asp94→Glu94 hereafter D94E) in the NS1-2 protein B-HT 920 2HCl confers the capacity for enteric persistence upon CW3 (11 23 In chimeric viruses the presence of the entire CW3 capsid gene or the protruding domain name of the CW3 capsid gene correlated with IFN-β and IFN-λ induction (fig. S3 A to F). Furthermore in CW3-derived viruses carrying the NS1-2 D94E mutation that confers persistence (CW3D94E) the presence of the CR6 capsid lessened IFN-β and IFN-λ induction Rabbit Polyclonal to EDNRA. in MLNs despite comparable levels of viral replication (Fig. 2C). This phenotype allowed us to use a chimeric virus to test the hypothesis that IFN-λ responses are required for prevention of persistence. The CW3D94E strain is usually capable of efficiently establishing enteric persistence only at low doses (fig. S4). When control mice were inoculated with a high dose of CW3D94E many mice failed to establish persistence (fig. B-HT 920 2HCl S4 and Fig. 2D). This failure of CW3D94E to persist was rescued by either the CR6 capsid protein which is usually associated with diminished IFN-β and IFN-λ responses (fig. S4) or by contamination of mice with CR6 and 21 days later treated with a single dose of IFN-λ. Enteric persistence of CR6 was cured by IFN-λ treatment of both control and mice and recombinant IFN-λ protein. The mouse norovirus strains used in this paper are available from Washington University under a material transfer agreement (MTA). mice were made available from ZymoGenetics (Bristol-Myers Squibb) under a MTA with Washington University School of Medicine. H.W.V. is usually a co-inventor on a patent filed by Washington University School of Medicine related to the use of murine norovirus. The data presented in this manuscript are tabulated in the main paper and in the supplementary materials. H.W.V. was supported by NIH grants R01 AI084887 and U19 AI109725 the Crohn’s and Colitis Foundation Genetics Initiative grant 274415 and Broad Foundation grant IBD-0357. M.S.D. and H.M.L. were supported by NIH grants U19 AI083019 and U19 B-HT 920 2HCl AI106772. T.J.N..