Tolerance phenomena in birds

Abstract

On this occasion I should like to speak about some of the recent research which has been carried out at our laboratory in Prague. We have continued our work on the immunological effects of embryonic parabiosis in birds and have made new analyses of the phenomenon of immunological tolerance. In our earlier work, when studying the after-effects of embryonic parabiosis between birds of the same species, we observed a complete suppression of agglutinin formation (Hašek 1953). Later we confirmed the results of Billingham, Brent & Medawar (1953) by showing that embryonic parabiosis causes tolerance of skin homografts (Hašek 1954). Embryonic parabiosis brings about an immunological tolerance which persists for a long time, sometimes perhaps throughout the individual’s life. Persistence of immunological tolerance has sometimes been observed even in birds 2 to 3 years of age. Billingham et al . (1956) described the occurrence of persistent blood chimerism after experimental embryonic parabiosis in chickens, an observation similar to that made earlier by Owen (1945) in his study of natural parabionts of cattle. I should first like to draw your attention to our results concerning the persistence of heterologous erythrocytes, and the occurrence of interspecific blood chimeras, after embryonic parabiosis between members of different species. By the 2nd or 3rd week after hatching, foreign red blood cells had already disappeared from the circulation of ducks which had been in parabiosis with hens and of hens which had been in parabiosis with ducks. The same result was obtained in the hen-guinea-fowl and hen-pheasant parabionts.