Species Specificity of Type III Interferon Activity and Development of a Sensitive Luciferase-Based Bioassay for Quantitation of Mouse Interferon-?.

ABSTRACT: The type III interferon (IFN-?) family includes 4 IFN-? subtypes in man. In the mouse, only the genes coding for IFN-?2 and -?3 are present. Unlike mouse and human type I IFNs (IFN-?/?), which exhibit strong species specificity, type III IFNs were reported to act in a cross-specific manner. We reexamined the cross-specificity and observed that mouse and human IFN-? exhibit some species specificity, although much less than type I IFNs. Mouse IFN-?3 displayed clear species specificity, being 25-fold less active in human cells than the closely related mouse IFN-?2. This specificity likely depends on amino acids in ? helices A and F that diverged from other IFN-? sequences. Human IFN-?4, in contrast, retained high activity in mouse cells. We next developed a firefly luciferase-based reporter cell line, named Fawa-?-luc, to detect IFN-? in biological fluids with high specificity and sensitivity. Fawa-?-luc cells, derived from mouse epithelial cells that are responsive to IFN-?, were made nonresponsive to type I IFNs by inactivation of the Ifnar2 gene and strongly responsive to IFN-? by overexpression of the mouse IFNLR1. This bioassay was as sensitive as a commercially available enzyme-linked immunosorbent assay in detecting mouse IFN-? in cell culture supernatant, as well as in serum and bronchoalveolar lavage samples of virus-infected mice. The assay also enabled the sensitive detection of human IFN-? activity, including that of the divergent IFN-?4 with a bias, however, due to variable activity of IFN-? subtypes.

SUBMITTER: Jacobs S 

PROVIDER: S-EPMC6249671 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature