Gaël Dulude

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Chronic exposure to oncostatin M (OM) has been shown to stimulate extrathymic T cell development. The present work shows that in OM transgenic mice, 1) massive extrathymic T cell development takes place exclusively the lymph nodes (LNs) and not in the bone marrow, liver, intestines, or spleen; and 2) LNs are the sole site where the size of the mature CD4+(More)
The thymus plays a crucial role in providing the immune system with naive T cells showing a diverse TCR repertoire. Whereas the diversity of thymic production is mainly ensured by TCR rearrangement at both the TRA and TRB loci, the number of cells reaching the double-positive differentiation stage defines the extent of thymic output. A quantitative analysis(More)
Thymic function is severely impaired in most marrow transplant recipients. To evaluate the impact of thymic hypoplasia on T cell reconstitution following marrow transplantation, we compared the phenotype and function of T lymphocytes in thymectomized recipients with those of euthymic hosts. Irradiated C57BL/6 mice (Thy1.2+, Ly5.1+) received 10(7) T(More)
The aim of this work was to decipher how graft-versus-host disease (GVHD) affects T cell production and homeostasis. In GVHD+ mice, thymic output was decreased fourfold relative to normal mice, but was sufficient to maintain a T cell repertoire with normal diversity in terms of Vbeta usage. Lymphoid hypoplasia in GVHD+ mice was caused mainly by a lessened(More)
Age-related thymic involution severely impairs immune responsiveness. Strategies to generate T cells extrathymically are therefore being explored with intense interest. We have demonstrated that T cells produced extrathymically were functionally deficient relative to thymus-derived T cells. The main limitation of extrathymic T cells is their undue(More)
Innate CD8 T cells are found in mutant mouse models, but whether they are produced in a normal thymus remains controversial. Using the RAG2p-GFP mouse model, we found that ∼10% of TCRαβ(+) CD4(-)CD8(+) thymocytes were innate polyclonal T cells (GFP(+)CD44(hi)). Relative to conventional T cells, innate CD8 thymocytes displayed increased cell surface amounts(More)
Oncostatin M (OM) transforms the lymph node (LN) into a "super lymphoid organ" with 2 striking features: massive thymus-independent T-cell development and major expansion of the memory T-cell pool. We report that T-cell development in the LckOM LN is regulated by a cyclooxygenase-2 (COX-2)-dependent neoangiogenesis involving high endothelial venules (HEVs).(More)
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