THYMUS IN MICE BEARING THE STEEL MUTATION - MORPHOLOGIC STUDIES ON FETAL, NEONATAL, ORGAN-CULTURED, AND GRAFTED FETAL THYMUS

  • 1 January 1981
    • journal article
    • research article
    • Vol. 45  (5) , 418-426
Abstract
Mice with the Steel mutation were studied to determine whether they showed a morphologic difference in the epithelial-reticular microenvironment of the thymus when compared with their normal and heterozygous littermate controls. Thymuses taken directly from fetal and newborn homozygous SlWehi/SlWehi mice, after culture, and after subcapsular renal grafting were compared by light microscopy and EM with similarly treated thymuses from heterozygous SlWehi/+ and normal homozygous (+/+) littermates. At all developmental stages studied, the homozygous mutants had smaller thymuses with fewer lymphoid cells than their homozygous normal and heterozygous littermates. The homozygous mutants also showed ultrastructural abnormalities in the thymic epithelial cells. After organ culture, homozygous fetal mutant thymuses produced fewer lymphocytes and showed abnormalities of epithelial cell ultrastructure when compared with littermate controls. When mutant and control fetal thymuses were grafted under opposite kidney capsules of normal syngeneic recipients, the mutant thymuses developed poorly and showed decreased lymphopoiesis and abnormalities of epithelial cell structure. A primary epithelial microenvironmental defect apparently exists in the thymus of mice with the Steel mutation.