Immunoglobulin Y (IgY) is the primary antibody found in the eggs of chicken (), allowing for large-scale antibody production with high titers, making them cost-effective antibody producers. IgY serves as a valuable alternative to mammalian antibodies typically used in immunodiagnostics and immunotherapy. Compared to mammalian antibodies, IgY offers several biochemical advantages, and its straightforward purification from egg yolk eliminates the need for invasive procedures like blood collection, reducing stress in animals. Due to the evolutionary differences between birds and mammals, chicken antibodies can bind to a broader range of epitopes on mammalian proteins than their mammalian counterparts. Studies have shown that chicken antibodies bind 3-5 times more effectively to rabbit IgG than swine antibodies, enhancing the signal in immunological assays. Additionally, IgY does not interact with rheumatoid factors or human anti-mouse IgG antibodies (HAMA), helping to minimize interference from these factors. IgY obtained from egg yolk of hens immunized against has been used in patients suffering from cystic fibrosis and chronic pulmonary colonization with this bacterium. Furthermore, IgY has been used to counteract in the oral cavity and for the treatment of enteral infections in both humans and animals. However, the use of avian antibodies is limited to pulmonary, enteral, or topical application and should, due to immunogenicity, not be used for systemic administration. Thus, IgY expands the range of strategies available for combating pathogens in medicine, as a promising candidate both as an alternative to antibiotics and as a valuable tool in research and diagnostics.
