IgA function - variations on a theme

JENNY M. WOOF* & MICHAEL A. KERR *Division of Pathology and Neuroscience, University of Dundee MedicalSchool, Ninewells Hospital, Dundee and Department of Clinical Biochemistry and Immunology, General Infirmary at Leeds,Leeds, UKImmunoglobulin A (IgA), as the major class of antibodypresent in the mucosal secretions of most mammals, rep-resents a key first line of defence against invasion by inhaledand ingested pathogens at the vulnerable mucosal surfaces.IgA is also found at significant concentrations in the serumof many species, where it functions as a second line ofdefence mediating elimination of pathogens that havebreached the mucosal surface. Receptors specific for the Fcregion of IgA, FcaR, are key mediators of IgA effectorfunction and studies described in this issue of Immunologyby Rogers and colleagues