Abstract
Mucosal surfaces in the gastrointestinal tract are continually exposed to native, commensal antigens and susceptible to foreign, infectious antigens. Immunoglobulin A (IgA) provides dual humoral responses that create a symbiotic environment for the resident gut microbiota and prevent the invasion of enteric pathogens. This review features recent immunological and microbial studies that elucidate the underlying IgA and microbiota-dependent mechanisms for mutualism at physiological conditions. IgA derailment and concurrent microbiota instability in pathological diseases are also discussed in detail. Highlights of this review underscore that the source of IgA and its structural form can dictate microbiota reactivity to sustain a diverse niche where both host and bacteria benefit. Other important studies emphasize IgA insufficiency can result in the bloom of opportunistic pathogens that encroach the intestinal epithelia and disseminate into circulation. The continual growth of knowledge in these subjects can lead to the development of therapeutics targeting IgA and/or the microbiota to treat life threatening diseases.
Highlights
Immunoglobulins (Ig), known as antibodies, are large Y-shaped glycoproteins produced by plasma cells
Out of the five Ig in the body, immunoglobulin A (IgA) is the second most abundant antibody found in circulation and the predominant antibody generated in mucosal secretions, whose primary function is to defend mucosal surfaces from pathogen invasion [1,2,3]
These lymphoid organs are composed of three, interactive layers that partake in IgA production: the B cell-rich follicles, the T cell-rich interfollicular zones and a subepithelial dome rich in CD11c+ dendritic cells (DCs) that separate the epithelium from the follicles
Summary
Immunoglobulins (Ig), known as antibodies, are large Y-shaped glycoproteins produced by plasma cells. Out of the five Ig in the body, immunoglobulin A (IgA) is the second most abundant antibody found in circulation and the predominant antibody generated in mucosal secretions, whose primary function is to defend mucosal surfaces (e.g., gastrointestinal and respiratory tracts) from pathogen invasion [1,2,3]. We begin by explaining in-depth the production of IgA through both T cell dependent and independent pathways, the divergent IgA subclasses, and the differential functions between circulating and secretory IgA (SIgA). We expand on how the robust reactivity between SIgA and the host microbiome can dictate species fitness and overall gut homeostasis. Continual research to decipher the IgA-dependent mechanisms for microbiota-immune stability has the potential to be therapeutically exploited in the defense against pathological diseases
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
