As with the other immunoglobulins, IgY is a class of proteins which are formed by the immune system in reaction to certain foreign substances, and specifically recognize them.
(Usually, mammals such as rabbits or goats are injected with the antigen of interest by the researcher or a contract laboratory.
)[3] Ducks produce a truncated form of IgY which is missing part of the Fc region.
Of the immunoglobulins arising during the immune response, only IgY is found in chicken eggs.
The yield of IgY from a chicken egg is comparable to that of IgG from rabbit serum.
[7] Antibody-containing blood serums, on the other hand, can sometimes be directly used in bioanalysis, i.e., without complicated isolation steps.
Particularly in Asian countries, IgY has been clinically tested as a food supplement and preservative.
Antibodies against Salmonella and other bacteria, as well as against viruses, are produced in this manner, and employed as a nutritional component for protection against these pathogens.