[Ontogeny of cardiac antigens in chickens]

The embryonic development of the heart is a complex process in which molecular events take place during the cellular recognition, growth regulation and morphogenesis. In this work, the stage in which cardiac antigens are produced in the chick embryo was established by the use of sera directed against cockerel's heart antigens. Chick embryos were studied in different stages of development, classified according to the Hamburger and Hamilton system. Soluble and insoluble fraction of the cockerel's heart were obtained and used to immunize rabbits; the presence of anti-heart antibodies was tested by double microimmunodiffusion. Antisera to yolk and albumin envelopment, serum and cockerel erythocytes were also produced in order to recognize other molecules in the embryos. Anticockerel red cells antibodies were determined by direct hemaglutination. It was shown that heart antigens appear since the second stage of embryonic development and remain during the whole development, although in some stages it seems that the concentration of some antigens decreases. It is possible that the molecular changes in the heart tissue are manifested as variations in concentration of the cardiac substances.