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ANTIGENS IN IMMUNITY
Author(s) -
Nossal GJV,
Ada GL,
Austin Caroline M
Publication year - 1964
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.1964.32
Subject(s) - germinal center , antigen , medullary cavity , lymph node , medulla , lymph , immune system , chemistry , pathology , reticulum , biology , anatomy , antibody , immunology , microbiology and biotechnology , endoplasmic reticulum , medicine , b cell
Summary Isolated flagella from Salmonella bacteria were trace‐labelled with carrier‐free 125 I or 131 I, and small amounts of antigen of high specific activity were injected into the hind foot‐pads of rats. The pattern of antigen localization and the series of cellular changes induced were subsequently followed by killing rats at various intervals and preparing autoradiographs of their popliteal and aortic lymph nodes. Excellent autoradiographs could be obtained with doses as small as 16 ng., which is in the vicinity of the lowest immunizing dose. The antigen localized predominantly in two sites: in the macrophages of the medullary sinuses of the nodes, and in the lymphoid follicles. The pattern of labelling over the follicles suggested that, here too, the antigen was contained in macrophages, but that those in the follicles had long dendritic branches closely associated with the lymph node reticulum. Typical germinal centres developed immediately deep to the labelled follicles within five to seven days. Though lines of grains extended into the germinal centre, it appeared more likely that this label was between, rather than in, the blast cells. In the medulla of the node, plasmacytopoiesis proceeded rapidly between the third and fifth day, after which plasma cells could be seen in the medullary cords in excessive numbers for at least 10 weeks. While macrophages in the medulla were heavily labelled, and there was thus some problem of “spray” of grains, especially when 131 I was used, it was clear that the majority of the plasma cells formed during the immune response exhibited background labelling only. This indicated that very little, if any, antigen was present in the antibody‐producing cells themselves.