EN
The aim of the research was to monitor the influence of neonatal thymectomy on the reactivity of chicken spleen structures. The investigations were carried out on chickens with the thymus removed on the 1st day after hatching and with antigen administered in the form of sheep erythrocytes (SRBC) at the age of 12 weeks. On days 6, 14 and 21 after antigen administration the spleen was taken out and histological slides were prepared. On the established area of HE slides germinal centres were counted and mature centres of type I and immature ones of type II were distinguished. Reaction to the acid phosphatase (APh) was done by the Gomori method. The results of the reaction was read on the established area within the periarterial lymphatic tissue (PAL) using the Thomson point method. It was found that neonatal thymectomy leads to a decrease in the number of germinal centres and simultaneously to the reduction of the intensity of APh reaction within the spleen PAL. Following immunization of the thymectomized chickens, in comparison to the control (group) a change of kinetics of germinal centers formation was discovered, mainly of type I. It was ascertained that in the succeeding days after the antigen administration the intensity of APh reaction within PAL was directly proportional to the number of immature germinal centres of type II. The results demonstrated a distinct association between the bursodependent and thymodependent spleen structures reactivity and confirmed the importance of the functional state of the thymus.