Cytokine regulation of prethymic T-lymphoid progenitor-cell proliferation and/or differentiation has not been well-defined, although much is known of cytokine regulation of hemopoietic stem- and progenitor-cell development. Here we use a recently identified hemopoietic growth factor, stem-cell factor (SCF) (a form of the c-kit ligand), and a transplant model of thymocyte regeneration to assess ...

Introduction: Monosodium glutamate (MSG) is one of the commonest food additives in modern nutrition. Recent studies showed the modulatory effect of MSG on rat thymocyte apoptosis in vivo and under in vitro conditions. However, the influence of MSG on thymocyte proliferation is largely unknown. Material and methods: We evaluated the effect of increased MSG concentrations on thymocyte proliferati...

We show that Indian Hedgehog (Ihh) regulates T-cell development and homeostasis in both fetal and adult thymus, controlling thymocyte number. Fetal Ihh(-/-) thymi had reduced differentiation to double-positive (DP) cell and reduced cell numbers compared with wild-type littermates. Surprisingly, fetal Ihh(+/-) thymi had increased thymocyte numbers and proportion of DP cells relative to wild type...

Adapter molecules that promote protein-protein interactions play a central role in T lymphocyte differentiation and activation. In this study, we examined the role of the T lymphocyte-expressed adapter protein and Src kinase substrate, Sin, on thymocyte function using transgenic mice expressing an activated, truncated allele of Sin (SinDeltaC). We found that SinDeltaC expression led to reduced ...

Pseudomonas exotoxin A, an ADP-ribosylating toxin produced by Pseudomonas aeruginosa, has been shown to stimulate the proliferation of murine thymocytes, which requires the participation of accessory cells. This requirement for accessory cells can be replaced by supernatant from adherent peritoneal exudate cells that have been stimulated with exotoxin A. Antibody to exotoxin A inhibits the indu...

We have previously demonstrated that 3,5,3'-tri-iodo-L-thyronine (T3) produces a very rapid and transient increase in calcium uptake and cytoplasmic free calcium concentration in the rat thymocyte, and have postulated that Ca2+-ATPase may contribute to the overall effect of T3 on cellular calcium metabolism. In the present study, we show that in the rat thymocyte, T3 increased plasma membrane C...

The elimination of autoreactive T cells occurs via thymocyte apoptosis and removal by thymic phagocytes, but the sequence of events in vivo, and the relationship between thymocyte death and phagocytic clearance, are unknown. Here we address these questions by following a synchronized cohort of thymocytes undergoing negative selection within a three-dimensional thymic tissue environment, from th...

Successive colonization of the thymus by waves of thymocyte progenitors has been described in chicken-quail chimeras and suggested from studies in mice. In swine, we show that the first CD3epsilon-bearing thymocytes appear on day 40 of gestation (DG40). These early thymocytes were CD3epsilonhigh and belonged to the gammadelta T cell lineage. Mature CD3epsilonhigh alphabeta thymocytes were obser...

Rabbit anti-thymocyte globulin is used worldwide to treat and prevent rejection in kidney transplantation. Multiple mechanisms of action of this polyclonal preparation are responsible for its success. Studies have supported clinical benefits of rabbit anti-thymocyte globulin in high immunological risk kidney transplant recipients when used as an induction agent at the time of transplant and for...

Mice deficient in the transmembrane protein tyrosine phosphatase CD45 exhibit a block in thymocyte development. To determine whether the block in thymocyte development was due to the inability to dephosphorylate the inhibitory phosphorylation site (Y505) in p56(lck) (Lck), we generated CD45-deficient mice that express transgenes for the Lck Y505F mutation and the DO11.10 T-cell antigen receptor...