Biomedical subjects

Iyadh Douagi

Publications and source records attributed to Iyadh Douagi.

3 recordsLinked to original sources

PubMed2025

SARS-CoV-2 infection and vaccination elicit distinct pharyngeal mucosal B cell responses in children.

Mucosal immunity is an important correlate of protection against respiratory infections such as SARS-CoV-2. Comparing B cell responses in the upper respiratory tract following vaccination and infection may offer unique insights into mucosal immunity. Here, we characterized antigen-specific B cells in the tonsils, adenoids, and peripheral blood of children who had been infected with SARS-CoV-2 or vaccinated with SARS-CoV-2 mRNA vaccines. SARS-CoV-2-specific switched memory B cells (BSM) and germinal center B cells were found in the blood and pharyngeal lymphoid tissues after vaccination or infection. However, infection generated a higher proportion of IgA+ BSM and CXCR3+CD21+ BSM, which showed distinct spatial localization, greater clonal expansion and increased propensity for plasma cell differentiation compared to their CXCR3- counterparts, accompanied by persistent activation of innate and T follicular helper cells in the tissues. Our data provide evidence for tissue-specific B cell memory after either SARS-CoV-2 vaccination or infection, but with distinct characteristics that can influence the quality, durability, and localization of immunity.

Journal Article↗

PubMed2002

Identification of the earliest prethymic bipotent T/NK progenitor in murine fetal liver.

This article describes the isolation of a novel cell population (B220(lo)c-kit(+)CD19(-)) in the fetal liver that represents 70% of T-cell precursors in this organ. Interestingly, these precursors showed a bipotent T-cell and natural killer cell (NK)- restricted reconstitution potential but completely lacked B and erythromyeloid differentiation capacity both in vivo and in vitro. Moreover, not only mature T-cell receptor (TCR)alphabeta(+) peripheral T cells but also TCRgammadelta(+) and TCRalphabeta(+)CD8alphaalpha(+) intestinal epithelial cells of extrathymic origin were generated in reconstituted mice. The presence of this population in the fetal liver of athymic embryos indicates its prethymic origin. The comparison of the phenotype and differentiation potential of B220(lo)c-kit(+)CD19(-) fetal liver cells with those of thymic T/NK progenitors indicates that this is the most immature common T/NK cell progenitor so far identified. These fetal liver progenitors may represent the immediate developmental step before thymic immigration.

Animals↗

PubMed2002

Lymphocyte commitment during embryonic development, in the mouse.

Multipotent hematopoietic stem cells (HSC) differentiate into mature cells in the fetal liver (FL) during embryonic development, and in the bone marrow (BM) in adult animals. Multilineage differentiation is accomplished by the stepwise commitment of stem cells that sequentially loose differentiation potential. The characterization of the intermediate lymphoid precursors isolated from both hematopoietic sites suggests that, in FL, their potential of differentiation as well as their growth factor requirements are apparently less strict than in the BM. This could be the result of different commitment strategies at those sites: stochastic in the FL and instructive in the BM.

Animals↗