CD21, the C3d/CD23/Epstein-Barr virus (EBV), receptor is expressed at low density on cells of the T lineage. Immature thymocytes express CD21 with high density. In the present study, we have analyzed the expression of CD21 during intrathymic maturation of T cells. An intense staining for CD21 was observed at the double-negative stage and at the stage of early acquisition of CD4. CD21 expression...

A mAb, 1-23, which recognizes a novel cell surface Ag on immature murine thymocytes (designated as IMT-1 for immature thymocyte antigen-1) was prepared. IMT-1 was found to be expressed on 40 to 50% of CD4-8- double negative (DN), 5 to 10% of CD4-8+, and 5 to 20% of CD4+8+ double positive (DP) thymocytes in adult mice, but not expressed on CD4+8- thymocytes or peripheral T lymphocytes. It was no...

A murine monoclonal antibody, designated 8H3, recognizes a cell surface antigen expressed exclusively on rat T lineage cells. 8H3 antibody immunoprecipitated 180-, 120-, and 90-kD components from rat thymocytes as well as splenic T cells under nonreducing conditions. 8H3 antibody specifically inhibited the binding of thymocytes to fibronectin. Furthermore, binding of rat thymocytes to immobiliz...

Only a small proportion of thymocytes survive T cell selection in the thymus and leave the thymus as mature T cells. The vast majority of thymocytes undergo cell death during selection, either due to failure to undergo positive selection on self peptide-MHC presented by thymic antigen presenting cells (APC) or due to negative selection. In the murine thymus it has been shown that most thymocyte...

Interaction of TCRs on CD4+CD8+ immature T cell with MHC-peptide complexes on stromal cells is required for positive and negative selection in the thymus. Identification and characterization of a subpopulation of CD4+CD8+ thymocytes undergoing selection in the thymus will aid in understanding the mechanisms underlying lineage commitment and thymic selection. Herein, we describe the expression o...

Background: Recent results have provided increasing evidence to support involvement of membrane damage in the mechanism of ionizing radiation induced killing of mammalian cells. These findings have stimulated renewed interest in evaluating the damage to membrane as a primary initiator in radiation-induced cell killing especially in apoptotic death. The present study was aimed to gain deeper ins...

Whereas there is considerable information on the phenotypic and functional maturation of T cell receptor (TCR) ot/3 thymocytes, comparatively little is known of the maturational processes that affect development of TCR-3//8 thymocytes. One class of 3,/8 T cells, those bearing the V3'3 gene product, are generated only during the early fetal stages of thymic development, and then migrate to the s...

Glucose metabolism in mammalian thymocytes is coupled to their development and selection in the thymus. In chickens, thymocytes develop in a low glucose concentration in ovo and a high glucose concentration posthatch. To determine the effect of glucose concentration on thymocyte glucose metabolism, embryonic thymic lobes were cultured in media containing varying glucose concentrations and thymo...

This study shows that the normal thymus produces immunoregulatory CD25+4+8- thymocytes capable of controlling self-reactive T cells. Transfer of thymocyte suspensions depleted of CD25+4+8- thymocytes, which constitute approximately 5% of steroid-resistant mature CD4+8- thymocytes in normal naive mice, produces various autoimmune diseases in syngeneic athymic nude mice. These CD25+4+8- thymocyte...

Recent studies have revealed that 10-20% of CD4+8- or CD4-8- thymocyte populations contain NK1.1+ T cell receptor (TCR)-alpha/beta+ cells. This subpopulation shows characteristics that are different from NK1.1- CD4+ or NK1.1- CD8+ T cells and seems to have developed in a manner different from NK1.1- T cells. Although extensive studies have been performed on the NK1.1+ TCR-alpha/beta+ thymocytes...