Ontogenesis of Immunity to Erythrocyte Antigens in the Chick.

Erythrocytes labelled with chromium⁵¹ were injected into embryos and young chicks and a similar challenge given soon after the majority of the initial dose had been eliminated. While tolerance was the typical response in embryos and chicks up to 3 days of age, immunity could be induced in most chicks from this time onwards. The intensity of the immune response increased rapidly until the 12th day of age. No maternal antibody could be detected. Pretreatment of the embryo with testosterone impaired the immune response of 14-day-old chicks. [ABSTRACT FROM AUTHOR]