Laying hens are highly cost-effective producers of polyclonal antibodies in comparison with mammals as the antibodies can be purified from egg yolk. The antibodies are called IgY to differentiate them from mammalian IgG antibodies. Avian antibodies represent both a reduction and refinement in animal use. The cost for producing IgY is lower than for mammalian antibodies as chicken housing is cheap and the isolation/separation process is economical, high yielding, uncomplicated and fast.
IgY antibodies do not cross-react with Fc receptors, mammalian immunoglobulins such as RF and HAMA or activate the complement system and thereby reducing the cause of false positive results in immunological assays. These properties have also made them attractive for peroral immunotherapy for a variety of gastrointestinal diseases, such as human rotaviruses, enterotoxigenic Escherichia coli and Salmonella spp. In the future the IgY technology offers great opportunities to be more widely used in immunotherapy, diagnostics and research.