[Eosinophilic granulocytes in the mouse thymus]

The morphological peculiarities and distribution of thymus eosinophils of 69 conventional Swiss mice in different stages of their prenatal and postnatal development have been investigated. Single granulocytes, located mainly in the cortical zone between the epithelial cells and lymphocytes have been observed. The early appearance of these cells (in 17-18 days old fetuses) and the simultaneous presence of mature eosinophils as well as of their precursors have been discussed with regard to the possibility for the mouse thymus to participate in the eosinophilopoiesis.