[Ultrastructural characteristics of the cortical macrophages in the murine thymus].

The authors examined the fine structure of cortical macrophages in the thymus of mice (Swiss), aged 4 months and killed by decapitation. They described the characteristic ultrastructural peculiarities, which enabled to distinguish macrophages from epithelial reticular cells as well as from the so called dark reticular cells with long cytoplasmic outgrowths in the cortex of the thymic lobule. The observed differences in the cytoplasmic characteristics were connected with the degree of the functional activity of the cortical macrophages.