[Development of the immune system in human ontogenesis]

The lecture presents information on the development of the immune organs in human foetus (thymus, spleen, lymph nodes, tonsilla, appendix, Peyer's plaques and blood) on the basis of literature and author's own data. Phenotypic composition of T- and B-lymphocytes in each organ and in the blood are given in both foetus and adults. The information presented is valid for the understanding of congenital immunodeficiencies and immunological confrontation between the mother and the foetus. It is shown that the thymic hormones may be present in the cells of some other organs close to the thymus by their origin.