Thymocyte development is accompanied by sequential changes in cell surface glycosylation. For example, medullary thymocytes have increased levels of alpha2,3-linked sialic acid and a loss of asialo core 1 O-glycans as compared to cortical thymocytes. Some of these changes have been linked to fine tuning of the T cell receptor avidity. We analyzed ST6Gal I transcript abundance and levels of alph...

Chemokines are likely to play an important role in regulating the trafficking of developing T cells within the thymus. By using anti-CD3varepsilon treatment of recombinase-activating gene 2 (Rag2-/-) mice to mimic pre-TCR signaling and drive thymocyte development to the double positive stage, we have identified murine GPR-9-6 as a chemokine receptor whose expression is strongly induced followin...

An important role for plexinD1 in thymic development is inferred from studies of germline Plxnd1 knockout (KO) mice where mislocalized CD69(+) thymocytes as well as ectopic thymic subcapsular medullary structures were observed. Given embryonic lethality of the Plxnd1 (-/-) genotype, fetal liver transplantation was employed in these prior analyses. Such embryonic hematopoietic reconstitution may...

There is little known about the regulation of gene expression during TCR-mediated differentiation of immature CD4+8+ (double positive) thymocytes into mature T cells. Using the DPK CD4+8+ thymocyte precursor cell line, we demonstrate that the early growth response-1 gene (Erg-1), encoding a zinc finger transcription factor, is rapidly upregulated after TCR stimulation. We also report that Egr-1...

Abstract Thymocytes progress toward mature T cells through a series of antigen-specific selection steps facilitated by thymic epithelial (TECs) in the cortex, site positive selection, and medulla, negative selection. TECs produce glucocorticoids (GCs), which enhance increase fitness cell repertoire, but TEC subpopultion does this, how it is regulated, unknown. We generated reporter mouse that e...

CD30 is a member of tumor necrosis factor (TNF) receptor superfamily that is expressed by activated T cells in the presence of interleukin-4 (IL-4). Although CD30 can mediate a variety of signals, CD30-deficient mice have impaired negative selection of T cells, suggesting that at least in the context of murine thymus, CD30 is a cell death-mediating molecule. The ligand for CD30 (CD30L) is a mem...

Promiscuous expression of tissue restricted antigens (TRAs) in medullary thymic epithelial cells (mTECs) is crucial for negative selection of self-reactive T cells to establish central tolerance. Intercellular transfer of self-peptide-MHC complexes from mTECs to thymic dendritic cells (DCs) allows DCs to acquire TRAs, which in turn contributes to negative selection and regulatory T cell generat...

To analyze the mechanisms responsible for thymocyte proliferation, maturation and migration in the thymus, the rat thymus just after, and recovering from irradiation was studied morphologically. The vascular structures of the rat thymus after a radiation dose of 6 Gy were found to be destroyed on day 3, but had recovered to almost normal by day 7, suggesting that the abrupt recovery of thymus s...