Distinct subsets of multi-lymphoid progenitors support ontogeny-related changes in human lymphopoiesis.

Changes in lymphocyte production patterns occurring across human ontogeny remain poorly defined. In this study, we demonstrate that human lymphopoiesis is supported by three waves of embryonic, fetal, and postnatal multi-lymphoid progenitors (MLPs) differing in CD7 and CD10 expression and their output of CD127 early lymphoid progenitors (ELPs). In addition, our results reveal that, like the fetal-to-adult switch in erythropoiesis, transition to postnatal life coincides with a shift from multilineage to B lineage-biased lymphopoiesis and an increase in production of CD127 ELPs, which persists until puberty.

Modeling Human Fetal Hematopoiesis in Humanized Mice.

Due to difficulties to access primary human bone marrow samples and age or donor effects, human hematopoiesis has long remained far less well characterized than in the mouse. Despite recent progresses in single-cell RNA profiling only little is known as to phenotype, function and developmental trajectories of human lymphomyeloid progenitors and precursors. This is especially true regarding the developmental architecture of the lymphoid lineage which has been the subject of persistent controversies over the past decades.

CD4CD8 T-Lymphocytes in Xenogeneic and Human Graft-versus-Host Disease.

Mechanisms driving acute graft-versus-host disease (aGVHD) onset in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) are still poorly understood. To provide a detailed characterization of tissue-infiltrating T lymphocytes (TL) and search for eventual site-specific specificities, we developed a xenogeneic model of aGVHD in immunodeficient mice. Phenotypic characterization of xenoreactive T lymphocytes (TL) in diseased mice disclosed a massive infiltration of GVHD target organs by an original CD4CD8 TL subset.

Drosophila larvae food intake cessation following exposure to Erwinia contaminated media requires odor perception, Trpa1 channel and evf virulence factor.

When exposed to microorganisms, animals use several protective strategies. On one hand, as elegantly exemplified in Drosophila melanogaster, the innate immune system recognizes microbial compounds and triggers an antimicrobial response. On the other hand, behaviors preventing an extensive contact with the microbes and thus reducing the risk of infection have been described.