Thymocytes differentiate in the thymic microenvironment into immunocompetent T cell through the interaction with a variety of accessory cells, including thymic epithelial cells (TEC). TEC plays an important role in the selection process presenting self antigens in association with major histocompatibility complex (MHC) molecules to the maturing T cells. The T cell receptor recognizes the self a...

PE-35 mouse monoclonal antibody (MoAb) (IgG1) detecting an epithelial antigen with a molecular weight of 35,000 was characterized serologically. Immunoperoxidase staining and double immunoenzymatic staining showed that PE-35 antigen is predominantly on nonlymphoid cells in the medulla of thymus. By immunoelectron microscopy, thymic epithelial cells in the medulla were positive with PE-35 MoAb, ...

The development of CD4(+) helper and CD8(+) cytotoxic T-cells expressing the αβ form of the T-cell receptor (αβTCR) takes place in the thymus, a primary lymphoid organ containing distinct cortical and medullary microenvironments. While the cortex represents a site of early T-cell precursor development, and the positive selection of CD4(+)8(+) thymocytes, the thymic medulla plays a key role in t...

Mature peripheral T cells respond to foreign but not to self-antigens. During development in the thymus, deletion of high-affinity self-reactive immature thymocytes contributes to tolerance of mature T cells. However, double-positive thymocytes are positively selected to survive if they respond to self-peptide-MHC complexes; thus, there must be mechanisms to prevent overt reactivity to those sa...

Liposome-entrapped dichloromethylene diphosphonate (Cl2MDP) was injected locally into the thymus of adult rats. This treatment, which has been found to deplete resident macrophages in other organs, also reduced the number of thymic macrophages. The depletion was evident in the cortex and the corticomedullary zone at 5, 13 and 23 days after Cl2MDP treatment, while the decrease in medullary macro...

Thymic epithelial cells (TECs) are the predominant intrathymic source of the essential thymopoietin IL-7. Whether thymocyte-TEC interactions have a role in the regulation of IL-7 expression is not known. By exploiting IL-7 reporter mice in which yellow fluorescent protein expression identifies TECs expressing high levels of IL-7 (Il7(+) TECs), we show that Il7(+) TECs segregate from emerging me...

Thymic epithelial cells (TECs) are critical for the normal development and function of the thymus. Here, we examined the developmental stages of TECs using quantitative assessment of the cortical and medullary markers Keratin 5 and Keratin 8 (K5 and K8) respectively, in normal and gain/loss of function mutant animals. Gain of function mice overexpressed RANKL in T cells, whereas loss of functio...

The study was undertaken to further elucidate a role of gonadal hormones in maintenance of normal thymocyte maturation and sexual dimorphism in the intrathymic T-cell development. Rats of both sexes were gonadectomized or sham-gonadectomized (controls) at age of 2 and 6 months, and 30 days later the thymus size, cellularity and thymocyte composition were evaluated. In both control and gonadecto...

Abstract Patients with combined immunodeficiencies can be cured by intravenous transfer of allogeneic hematopoietic stem and progenitor cells (HSPC). However, complications such as an impaired delayed T cell differentiation are unfortunately common, notably due to the defective thymic architecture in these patients requirement HSPC homing thymus. To circumvent problems, we have developed innova...