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AUTORADIOGRAPHIC OBSERVATIONS ON THE LOCATION OF DNA— AND RNA— SYNTHESIZING CELLS IN RAT POPLITEAL LYMPH NODESM
Author(s) -
Miller JJ
Publication year - 1965
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.1965.9
Subject(s) - lymph , lymph node , reticular cell , rna , spleen , thymidine , dna synthesis , medulla , cell , microbiology and biotechnology , pathology , chemistry , biology , dna , immunology , anatomy , biochemistry , medicine , gene
Summary 3 H‐thymidine and 3 H‐cytidine have been used to study the histological localization of DNA‐ and RNA‐synthesizing cells in popliteal lymph nodes from untreated, immunized and neonatally thymectomized rats. Active cell proliferation, as measured by 3 H‐thymidine incorporation, was demonstrated in the medulla of unstimulated nodes from normal and from neonatally thymectomized rats. After an immunological stimulus, an early increase in medullary cell proliferation was associated with a similar but less intense reaction in the cortex. A partial dissociation between the sites of cell proliferation and the sites of most active RNA synthesis was noted. Cells with the highest apparent RNA‐synthetic rates were found predominantly in the cortex. Reticular cells, histiocytes, and plasma cells were found to retain labelled RNA longer than the other cells of the lymph nodes. The ability to achieve considerably more intense labelling in popliteal lymph node cells than in the rest of the lymphoid system by hind foot‐pad injections of 3 H‐nucleosides was confirmed. However, attempts to use this finding for a study of lymph node cell migration were complicated by a failure to obtain adequate numbers of labelled cells after injection of 3 H‐thymidine, and by the difficulty of finding a dose of 3 H‐cytidine which labelled small lymphocytes in the popliteal nodes but not blast cells in other organs. It was possible, however, to demonstrate lymphocyte migration within 30 minutes of selective labelling of one popliteal node. Small numbers of migrant cells were found in other lymph nodes, spleen, thymus, and ileal submucosa.