Revisiting the B-cell compartment in mouse and humans: more than one B-cell subset exists in the marginal zone and beyond.

International audienceABSTRACT: The immunological roles of B-cells are being revealed as increasingly complex by functions that are largely beyond their commitment to differentiate into plasma cells and produce antibodies, the key molecular protagonists of innate immunity, and also by their compartmentalisation, a more recently acknowledged property of this immune cell category. For decades, B-cells have been recognised by their expression of an immunoglobulin that serves the function of an antigen receptor, which mediates intracellular signalling assisted by companion molecules. As such, B-cells were considered simple in their functioning compared to the other major type of immune cell, the T-lymphocytes, which comprise conventional T-lymphocyte subsets with seminal roles in homeostasis and pathology, and non-conventional T-lymphocyte subsets for which increasing knowledge is accumulating. Since the discovery that the B-cell family included two distinct categories - the non-conventional, or extrafollicular, B1 cells, that have mainly been characterised in the mouse; and the conventional, or lymph node type, B2 cells - plus the detailed description of the main B-cell regulator, FcγRIIb, and the function of CD40+ antigen presenting cells as committed/memory B-cells, progress in B-cell physiology has been slower than in other areas of immunology. Cellular and molecular tools have enabled the revival of innate immunity by allowing almost all aspects of cellular immunology to be re-visited. As such, B-cells were found to express "Pathogen Recognition Receptors" such as TLRs, and use them in concert with B-cell signalling during innate and adaptive immunity. An era of B-cell phenotypic and functional analysis thus began that encompassed the study of B-cell microanatomy principally in the lymph nodes, spleen and mucosae. The novel discovery of the differential localisation of B-cells with distinct phenotypes and functions revealed the compartmentalisation of B-cells. This review thus aims to describe novel findings regarding the B-cell compartments found in the mouse as a model organism, and in human physiology and pathology. It must be emphasised that some differences are noticeable between the mouse and human systems, thus increasing the complexity of B-cell compartmentalisation. Special attention will be given to the (lymph node and spleen) marginal zones, which represent major crossroads for B-cell types and functions and a challenge for understanding better the role of B-cell specificities in innate and adaptive immunology

Modeling of indoor air treatment using an innovative photocatalytic luminous textile: Reactor compactness and mass transfer enhancement

International audienceIndoor air pollution is a complex problem that involves a wide range and diversity of pollutants that threaten human health. In this context, significant efforts must be made to improve the quality of indoor air. It is therefore important to start controlling the sources of indoor pollution. However, where eliminating or minimizing sources of emissions is not technically feasible, technologies to reduce them should be used. The present work deals with the photocatalytic depollution of hospitals indoor air, using a continuous photocatalytic process. In order to get closer to real conditions, two model pollutants representing the indoor air of hospitals were chosen as targets; chloroform (CHCl3) and glutaraldehyde (C5H8O2). The photocatalytic oxidation of VOCs alone and their mixture (binary mixing system) has been studied on a pilot scale. Indeed, the experiments were carried out in a continuous planar reactor using a new technology based on the TiO2/optical fiber photocatalyst. The effects of experimental conditions such as air flow rate (4–12 m3.h−1), VOCs inlet concentration (4–40 mg.m−3) and humidity levels (5–90%) were pointed out. The photocatalytic effect of the OF-TiO2 composite was found to be improved under UV irradiation as compared to TiO2. The presence of water molecules in small amounts (less than RH = 30%) can promote the degradation process due to the formation of •OH radicals. Biomolecular Langmuir-Hinshelwood model including mass transfer step has been developed to represent the process behavior. Reusability test show that the optical fiber -based photocatalysts presented good photocatalytic activities towards CHCl3/C5H8O2 removal. © 2021 Elsevier B.V

Membrane fibres creuse auto-nettoyantes en PVP-PVDF-TiO2 : évolution des propriétés sous irradiation UV

International audienc