Embryotoxic effects of tissue antisera on the early chick embryo in vitro.

Abstract

<p> Chick embryos at stages primitive streak to three somites were explanted on the vitelline membrane and cultured by the method of New (1955) or by Gallera's modification of the method (Nicolet and Gallera. 1963). Antisera produced in rabbits against adult chicken brain extract. adult chicken kidney extract. and embryo brain extract were placed on the uppermost side of the embryo preparation. The embryos were recovered after 24 to 36 hours further incubation. Defects of the central nervous system. the posterior trunk. and the extra-embryonic membranes occurred in embryos exposed to adult brain antiserum. Embryos exposed to adult kidney antiserum developed exactly the same kinds of defects. Embryo brain antiserum produced similar abnormalities which included defects of the central nervous system and of the extra-embryonic membranes, and in addition de-. fective somites. However, embryos exposed to gamma globulin solutions containing antibodies against neural-specific antigens and not against common tissue antigens were normal. In control experiments, embryos exposed to saline solution, to normal rabbit serum, and to normal rabbit serum gamma globulins developed normally. </p> <p> Histological examination of ~epresentative antisera treated embryos revealed that there were extensive areas of disorganization and necrosis of neural tissue. In embryos with short trunks, the caudal proliferation centre was necrotic. Embryos exposed to gamma globulins of absorbed adult brain antiserum were histologically normal. </p> <p> The antisera used in these experiments were characterized by double diffusion in agar gel. It was demonstrated by this method that the antisera contained antibodies against common tissue antigens as well as against tissue-specific antigens. It was also shown that certain antigens common to all adult organs were present in the embryo and in the extra-embryonic membranes during the time that the embryos were exposed to the antisera. </p> <p> Embryos which had been exposed to various of the tissue antisera for 8.5, 21.5 or 32 hours were sectioned. The sections were stained with FITC-labelled goat anti-rabbit gamma globulins in order to localize distribution of the antibodies. Fluorescence was located on the ectoderm of the embryos and of their extra-embryonic membranes, in the lumen of the neural tube and in the cavity of the otic vesicles. This demonstrated that, under the conditions of the experiment, the antibodies were available to the embryo. </p> <p> Antisera which affected the embryo and the extra-embryonic membranes were shown to contain antibodies against antigens actually present in the embryos and in the extra-embryonic membranes during the time of exposure. The only antiserum which had no adverse effects on the embryos was the one which contained only antibodies against antigens not demonstrated to be present in the embryo during the time of exposure. </p>