On the nature of the periellipsoidal lymphoid tissue of chick spleen.

Abstract

Postnatal development of the splenic lymphoid tissue under normal and experimental conditions was investigated, using male White Leghorn chickens. It was evidenced that the white pulp of the chick spleen was composed of the periarterial and periellipsoidal lymphoid tissues, which were distinguishable from each other in the following aspects, i.e. mode of development, morphology of their constituting lymphoid cells, and relation to the germinal center formation. Along the venous channels in the splenic pulp, there often occurred perivenous lymphoid tissue of which structures were similar to those of the periarterial lymphoid tissue. To inhibit or retard the development of the bursal lymphopoiesis, the following experimental procedures were used: neonatal bursectomy and X-irradiation, hormonal bursectomy, neonatal whole body irradiation followed by repeated local irradiations of the lower part of the body. It was noted that the lack of the development of the periellipsoidal lymphoid tissue occurred under such experimental conditions. On the other hand, early extirpation or destruction of the thymus, i.e. neonatal thymectomy and X-irradiation or neonatal whole body irradiation with successive irradiations of the neck did not show any inhibitory effect on the development of the periellipsoidal lymphoid tissue. These findings strongly suggested the bursa-dependency of the periellipsoidal lymphoid tissue.