Novel functions of the polymeric Ig receptor: well beyond transport of immunoglobulins.
The polymeric Ig receptor (pIgR) ensures efficient secretion of polymeric IgA (pIgA) at mucosal surfaces. On basal to apical transport across epithelial cells, the pIgR extracellular domain is cleaved, releasing secretory component (SC) in association with pIgA. This finds its raison d'être in the recent observation that SC is directly involved in the protective function of secretory IgA. In addition, free SC exhibits scavenger properties with respect to enteric pathogens. However, although pIgR dedicates its life to mucosal protection, it also seems to permit pathogen entrance through the epithelial barrier. The multiple mechanisms that they are involved in make pIgR and SC instrumental to mucosal immunity.
Phalipon
Armelle
A
Unité de Pathogénie Microbienne Moléculaire, INSERM U 389, Institut Pasteur, 28 rue du Dr Roux, 75015 Paris, France.
Corthésy
Blaise
B
D000818:Animals; D004848:Epithelium / Q000276:immunology / Q000382:microbiology; D006801:Humans; D018928:Immunity, Mucosal; D007070:Immunoglobulin A / Q000378:metabolism; D007071:Immunoglobulin A, Secretory / Q000378:metabolism; D018448:Models, Immunological; D009092:Mucous Membrane / Q000276:immunology; D019056:Receptors, Polymeric Immunoglobulin / Q000378:metabolism*; D012635:Secretory Component / Q000378:metabolism
D007070:Immunoglobulin A; D007071:Immunoglobulin A, Secretory; D019056:Receptors, Polymeric Immunoglobulin; D012635:Secretory Component; C034639:polymeric IgA