[Effects of the age of the recipient on the outcome of transplantation of lymphoid organs from newborn donors].

The comparison of developmental capacities of simultaneously grafted thymus and spleen taken from newborn CBA mice in young and old macroenvironment was attempted using the method of heterotopic chimera construction. The perceptible augmentation of immune response in both host and donor spleens was obtained in case of transplantation into the young animals, and completely opposite effect, i. e. well-marked immunosuppression in case of old recipients. Preliminary removal of host spleen results in abolition of this suppressive effect in old animals. Moreover, immune response in donor spleen following thymus transplantation into the old splenectomized recipients was significantly higher compared to the same one without additional thymus graft. Taken together, these findings indicate that despite the existence of some potency for autonomous development the eventual effect of neonatal lymphoid organs maturation strongly depends upon the age of system in which this maturation does take place.