Epithelial–immune cell interactions in allergic diseases

Abstract

Epithelial/immune interactions are characterized by the different properties of the various epithelial tissues, the mediators involved, and the varying immune cells that initiate, sustain, or abrogate allergic diseases on the surface. The intestinal mucosa, respiratory mucosa, and regular skin feature structural differences according to their primary function and surroundings. In the context of these specialized functions, the active role of the epithelium in shaping immune responses is increasingly recognizable. Crosstalk between epithelial and immune cells plays an important role in maintaining homeostatic conditions. While cells of the myeloid cell lineage, mainly macrophages, are the dominating immune cell population in the skin and the respiratory tract, lymphocytes comprise most intraepithelial immune cells in the intestine under healthy conditions. Common to all surface epithelia is the fact that innate immune cells represent the first line of immunosurveillance that either directly defeats invading pathogens or initiates and coordinates more effective successive immune responses involving adaptive immune cells and effector cells. Pharmacological approaches for the treatment of allergic and chronic inflammatory diseases involving epithelial barriers target immunological mediators downstream of the epithelium (such as IL‐4, IL‐5, IL‐13, and IgE). The next generation of therapeutics involves upstream events of the inflammatory cascade, such as epithelial‐derived alarmins and related mediators.

mRNA Technology and Mucosal Immunization

“…Thus, the mucosal compartment represents a preeminent portion of the immune system. At different anatomical sites, mucosal epithelia have distinctive organizations, but the configuration of follicles, interfollicular regions, subepithelial dome regions, and follicle-associated epithelial cells is consistent [ 10 ]. Leukocytes residing in the lamina propria of mucosae include the intraepithelial lymphocytes, i.e., a population of cells located at the surface epithelium in an environment characterized by constant and diverse antigenic encounters with environmental and microbial constituents.…”