Binding chicken Anx2 is beneficial for infection with infectious bursal disease virus

• The identification of host cellular molecules that binds with virus will improve the understanding of the pathogenic mechanism. However, the identification of a specific protein of host cell for the binding of IBDV has been elusive. In this study, a new molecular, chicken Anx2 was identified that can bind with IBDV.
• Previous reporters showed that Anx2 implicated in the infection of certain viruses. However, the role of Anx2 in the IBDV infection is unknown. In this study, we first identified chicken Anx2 as binding protein of IBDV and showed that binding with Anx2 is beneficial for IBDV infection.

Infectious bursal disease virus (IBDV) causes a highly contagious disease in young chickens and leads to significant economic loss in the poultry industry. The identification of host cellular molecules that bind to IBDV will improve the understanding of the underlying pathogenic mechanisms. In this study, using a virus overlay protein-binding assay (VOPBA) and mass spectrometry (MS) analysis, IBDV was found to bind chicken Anx2, a membrane protein fraction from DF-1 cells. Its interactions were further confirmed by an overlay assay. The results of an immunofluorescence assay and flow cytometry showed that Anx2 could be expressed and colocalized with IBDV on the surface of infected cells. Moreover, either the soluble recombinant Anx2 or an anti-Anx2 antibody could inhibit IBDV binding to and infection of DF-1 cells in a dose-dependent manner. The knockdown of Anx2 of DF-1 cells by small interfering RNA clearly reduced the subsequent virus yield, and overexpression of Anx2 was capable of enhancing the virus yield. These results indicate, for the first time, that binding to Anx2 is beneficial for IBDV infection.