Preparation and characterization of egg yolk immunoglobulin Y specific to influenza B virus

The aim of this study was to prepare egg yolk immunoglobulin (IgY) for use in the prevention and treatment of influenza B viral infections. Laying hens were immunized with inactivated influenza B virus (IBV), and IgY was isolated from the egg yolk by multiple polyethylene glycol (PEG) 6000 extraction and ammonium sulfate purification steps. The titers and specificity of the purified antibodies were assessed. The specific IgY titer increased beginning the second week after the first immunization, with the titer peaking at the fifth week. The yield of IgY was 76.5 mg per yolk, and the purity was 98.2%. The use of western blotting and the hemagglutination inhibition (HI) test demonstrated that IBV-specific IgY binds specifically to influenza B virus proteins, and a plaque reduction assay revealed the neutralization efficacy of IBV-specific IgY at reducing influenza infection in MDCK cells. Furthermore, when mice were treated intranasally prior to or after influenza B virus infection, IBV-specific IgY protected the mice from influenza infection or reduced viral replication in their lungs, respectively. These findings indicate that IgY is an easily prepared and rich source of antibodies that offers a potential alternative strategy for preventing and treating influenza B infections. (C) 2011 Elsevier B.V. All rights reserved.