Massive Migration of Thymic Lymphocytes to Peyer’s Patches in Neonatal Mice
Although migration of cells from the thymus to intestinal lymphoid tissues has been demonstrated in young animals (l–3), the magnitude of this process remains to be clarified, particularly during the early development of these tissues. Neonatal mice are useful experimental animals in which to study this problem. The Peyer’s patches of newborn mice are poorly developed at birth and contain only a small number of lymphoid cells (4), however, within 2 or 3 days after birth, the number of lymphoid cells increases markedly. Kinetic studies suggest that during this same developmental period there is an extensive emigration of thymic lymphoid cells (5–7). Systemic labeling data in newborn mice have provided evidence for a substantial immigration of lymphocytes into Peyer’s patches (8). These observations focus on the question of whether the gut associated lymphoid tissue in mice is a “primary” lymphoid organ as was proposed for the bursa of Fabricius in birds (9,10,11) or a “secondary” organ whose immunological development is, at least in part, thymus-dependent.
KeywordsLabel Index Lymphoid Cell Neonatal Mouse Newborn Mouse Thymic Lymphocyte
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