Interferon-Lambda: A Potent Regulator of Intestinal Viral Infections

Lee, Sanghyun; Baldridge, Megan T.

A final critical factor for discussion of enteric viral infections and IFN-λ is the role of the commensal bacterial microbiome. For these viruses, infection occurs amidst the complex milieu of the oral and intestinal microbiome, which plays important roles in regulation of viral infectivity. Poliovirus, reovirus, and murine mammary tumor virus depend upon the presence of commensal bacteria for infection (82, 83) , with direct viral binding to bacterial products like lipopolysacchide implicated as the mechanism of facilitation (84, 85) . Depletion of the commensal microbiota also impairs RV infection and results in enhancement of both mucosal and systemic antibody responses against the virus (86) . Human NoV binds directly to bacterial products that mimic the histo-blood group antigens (HBGAs) known to be attachment factors for NoV (87) (88) (89) , and indeed culture of human NoV in B cells depends on the presence of these HBGA-expressing bacteria (57, 90) . Hence, there is a common theme for enteric viruses in interacting with and depending on intestinal bacteria for infectivity, though the specific mechanisms may be virus dependent (91, 92) .