Development of maternal IgG-free chick obtained from surgically bursectomized hen

IgG-free eggs and chicks were developed, so as to study the role of maternal IgG in the development of the immune system. Surgical bursectomy on the 18th day of incubation deprived chickens of B cells and eliminated IgG synthesis. Bursectomized chickens are usually dead before sexual maturity under conventional conditions. When surgically bursectomized chickens were housed in an isolated clean room and antibiotics were administered to them, they could survive to sexual maturity. Finally, we succeeded in obtaining IgG-free fertilized eggs and maternal IgG-free chicks from surgically bursectomized hens. The amount of yolk IgG in IgG-free eggs was one-ten thousandth less than that in normal eggs. The level of IgM in the serum of maternal IgG-free chicks reached six times higher than that of normal chicks 5 days after hatching.