T Lymphocyte Precursors Migrate Towards Chemotactic Peptides Secreted by Embryonic or Juvenile Thymus
During embryonic life the thymic rudiment is extensively seeded by invading hemopoietic precursors that give rise to mature T cells (1). In birds thymus, colonization by precursor cells is limited to two defined time periods of embryonic development (2). The first hemopoietic precursor cells appear at day 5 in the thymus of quail embryos. At this stage of development the precursors were enriched in the perithymic region. These precursors are often in contact with endothelial cells of the jugular vein, a prefered site of extravasation; they are also dispersed within the mesenchymal tissue around the thymus, and adhere to the basal lamina that separates the thymus from the mesenchyme (3).
KeywordsConditioned Medium Boyden Chamber Thymic Epithelial Cell Chemotactic Migration Chemotactic Peptide
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