Abstract
The IgG found in serum of hen is accumulated into egg yolk to provide an acquired immunity to the offspring. An antibody in egg yolk has been referred to as IgY. It is now possible to produce specific IgY through eggs from hens immunized with a given antigen (proteins, bacteria, and viruses) instead of producing IgG through the blood of immunized animal such as rabbits or goats. One of useful application of IgY is in the fields of diagnosis using its binding specificity to given antigens as same as that of mammalian serum IgG. Another important use of IgY is for passive immunization therapy wherein its specific binding ability to the antigens (pathogens, venoms, etc.) serves to neutralize the pathogenicity of antigen. In this article, applications of IgY in diagnosis reagents and in prevention of infectious diseases are introduced.
