Research Areas

IgY and passive immunity

Transmission of antibodies from mother to child

In mammals, the fetus grows inside the mother’s womb until it is fully developed for childbirth. However, newborns lack the robust immune system needed to defend against bacteria, viruses, and other pathogens ubiquitous outside the womb. For this reason, newborns are dependent on antibodies transferred from their mother. This temporary dependence on the mother’s immune system after childbirth is called “maternal immunity”.。

In humans, antibodies are transmitted across the placenta to the fetus before birth and through breast milk to the offspring after delivery. In other mammals, antibodies are also passed from mother to child through breast milk.

Avian maternal immunity

The same maternal immune system that protects mammalian offspring exists in birds, but they are inherently incapable of relying on placenta or milk (as birds have neither). The avian solution is to stock maternal antibodies in the eggs, especially the yolk. Thus, when a chick develops from an egg, it already has antibodies inherited from its mother to protect it from external pathogens.

Passive immunity using avian maternal immunity

The immunity that an animal acquires throughout its life is called “acquired immunity”. On the other hand, immunity acquired from the outside through antibodies is called “passive immunity”. An example of passive immunization is giving her IgY from a bird to humans or livestock. When chickens are exposed to human or domestic pathogens, antibodies against these pathogens are produced and accumulate in the chicken egg yolk. These egg antibodies can be used to prevent infection and provide passive immunity to eliminate pathogens in both humans and livestock.