ONTOGENESIS OF IMMUNOLOGICAL COMPETENCE OF LYMPHOCYTES IN CHICKEN SKIN

Abstract

The earliest appearance of immunological competence against transplantation antigens has been shown in 3-day-old chick skin since when it was grafted on the chorioallantoic membrane weak splenomegaly was induced in the embryo. This has been confirmed by the ability of skin from 2-day-old parental strain chicks to reject inself when grafted on genetically tolerant F1 hybrid adults. The greatest concentration of lymphocytes appears in chick skin at 15 days of age when grafts of such skin can function as effectively as a source of lymphocytes as adult spleen. Skin from parental strain newly hatched and day-old chicks contained so few lymphocytes that it was "tolerant-responsive" and such grafts remained on the genetically tolerant F1 adults. These results suggest explanations for many curious phenomena in skin transplantation in chickens.