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THE ULTRASTRUCTURE OF THE NEONATAL THYMUS OF A MARSUPIAL, SETONIX BRACHYURUS
Author(s) -
Yadav M,
Papadimitriou JM
Publication year - 1969
Publication title -
australian journal of experimental biology and medical science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0004-945X
DOI - 10.1038/icb.1969.163
Subject(s) - marsupial , ultrastructure , biology , thymocyte , parenchyma , lymphocyte , anatomy , pathology , zoology , immunology , t cell , immune system , medicine , botany
Summary The superficial thymus glands of 14 neonatal qnokkas (Setonix brachyurus) , 0 to 24 days old, were examined under the electron microscope in an attempt to establish the origin of thymus lymphocytes. In the first 48 hours of post‐natal life the thymic parenchyma was entirely composed of undifferentiated epithelial cells. By the third and forth day a few thymic lymphocytes appeared amongst the epithelial cells which now exhibited increased differentiation and organisation. The proportion of thymus lymphocytes was greatly increased in older animals. In a few instances small lymphocyte‐like cells were observed traversing the junctions between endothelial cells of capillary vessels. No epithelial‐thymocyte transformations were observed. The mode of origin of thymus lymphocytes is discussed, and an extrathymic origin for the initial thymus lymphocytes is suggested.