[Histochemical studies of acid phosphatase in the bursa-dependent lymphoid tissue of the spleen of chickens after bursectomy and stimulation with ovine erythrocytes].

The experimental material were female chicks of Tetra SL cross-breed. It was found out that in the spleens of 8-week old chicks, bursectomized in the neonatal period, there occurred not only a decrease in the number of type I and II germinal centres, but also weakening of the reaction to acid phosphatase as well in those organic structures as in periellipsoidal lymphatic tissue. Single administration of sheep red blood cells to the chicks exerted varied effects on the germinal centres in the spleen depending on whether the recipient chicks had or had not been bursectomized. In non-bursectomized chicks there was observed an increase in the number of both types centres as well as intensified in them reaction to acid phosphatase. Now, after administration of the antigen to bursectomized chicks only the number of type II germinal centres was found to have increased with intensified in them reaction to acid phosphatase, while the number of type I centres and intensity of reaction to acid phosphatase stayed almost unchanged, i.e. at the level lowered by bursectomy. On these grounds it may be thought that only type II reproductive centres retain their reactivity to administration of the antigen irrespective of whether the chicks had or had not been bursectomized. Now, the sensitivity of type I centres of the spleen seems to be influenced, first of all, by the biological function of bursa Fabricii. Reactivity similar to that manifested by type I germinal centres, i.e. intensified reaction to acid phosphatase and growth after administration of antigen, was found also in periellipsoidal lymphatic tissue, though, only in non--bursectomized chicks. In the aspect of this research the results obtained constitute the basis for further study of the mechanism of immunological response in chicks.