Identification of Type III Interferon (IFN-λ) in Chinese Goose: Gene Structure, Age-Dependent Expression Profile, and Antiviral Immune Characteristics In Vivo and In Vitro.

Type III interferons (IFN-λ1/λ2/λ3, also known as IL-29/28A/28B, and IFN-λ4) are a recently discovered interferon group. In this study, we first identified the Chinese goose IFN-λ (goIFN-λ). The full-length sequence of goIFN-λ was found to be 823 bp. There was only one open reading frame that contained 570 bp, and, encoded 189 amino acids. The predicted goIFN-λ protein showed 78%, 67%, and 40% amino acid identity with duIFN-λ, chIFN-λ, and hIFN-λ3, respectively. The tissue distribution of goIFN-λ existed as a parallel distribution with goIFNLR1 as its functional receptor, which was mainly expressed in epithelium-rich tissues, such as lung, gizzard, proventriculus, skin and pancreas, and immune tissues, such as harderian gland and thymus. Furthermore, the immunological characteristics studies of goIFN-λ showed that there was a significant increase in the mRNA at the transcriptional level of goIFN-λ after the peripheral blood mononuclear cells were stimulated with ploy (I:C) and ODN2006, and infected with Gosling plague virus (GPV). In vivo, the mRNA transcriptional level of goIFN-λ increased nearly 20 times in the lung tissue and nearly 40 times in the pancreatic tissue after being artificially infected with H9N2 AIV. It is suggested that goIFN-λ might play a pivotal role in the mucosal immune protection and antiviral defense.