IGA

IGA
Name	Immunoglobulin A
Uniprot	P0CG05
Organism	Homo sapiens
Length	variable

IGA

Immunoglobulin A is a class of antibody prominent in mucosal and secretory immunity, found in blood plasma, saliva, tears, and secretions. It plays central roles at interfaces like the respiratory and gastrointestinal tracts, interacting with pathogens, commensals, and host cells to maintain homeostasis. Research spans molecular biology, clinical medicine, pediatrics, gastroenterology, pulmonology, nephrology, and immunotherapy.

Overview

IgA is synthesized by plasma cells in mucosa-associated lymphoid tissues such as the tonsils, Peyer’s patches, and the appendix, and circulates as serum IgA produced by bone marrow plasma cells. Studies often reference lymphoid organs like the spleen, thymus, and bone marrow, and landmark investigators and institutions including Élie Metchnikoff, Karl Landsteiner, Paul Ehrlich, the Pasteur Institute, the Royal Society, the National Institutes of Health, and the Wellcome Trust for historical context. Clinical relevance is highlighted in settings described by the World Health Organization, Centers for Disease Control and Prevention, European Medicines Agency, and national immunization programs. Epidemiological and public-health discussions frequently mention outbreaks and pandemics cataloged by the World Health Organization, the European Centre for Disease Prevention and Control, and the John Snow Society.

Structure and Biochemistry

IgA exists primarily as monomeric serum IgA and dimeric secretory IgA (sIgA) that incorporates the J chain and secretory component from the polymeric immunoglobulin receptor expressed by epithelial cells. Structural biology draws on work from the Protein Data Bank, cryo-electron microscopy centers such as the MRC Laboratory of Molecular Biology, and X-ray crystallography efforts at institutions like the Max Planck Institute, the RIKEN Institute, and EMBL. Molecular interactions reference proteins and complexes studied at places like the Scripps Research Institute, Cold Spring Harbor Laboratory, and the Francis Crick Institute. Glycosylation patterns analyzed by mass spectrometry labs at the Broad Institute, Harvard Medical School, and MIT show heterogeneity that affects binding to receptors such as FcαRI (CD89) characterized in studies from Johns Hopkins University, Yale School of Medicine, and the Karolinska Institutet. Comparative immunology includes analyses involving model organisms and species collections at the Smithsonian Institution, the Natural History Museum, and the American Museum of Natural History.

Biological Function and Immunology

IgA mediates immune exclusion, neutralization, and interaction with innate immune effectors in mucosal surfaces in collaboration with components and pathways studied by researchers at institutions such as Rockefeller University, Institut Pasteur, University College London, and the University of Tokyo. Its role in oral tolerance, neonatal immunity via breast milk investigated at Boston Children’s Hospital and Great Ormond Street Hospital, and microbiome modulation explored by teams at the Chan Zuckerberg Biohub, Wellcome Sanger Institute, and Institut Pasteur link to microbiology groups at the Pasteur Institute, Centers for Disease Control and Prevention, and the Robert Koch Institute. Immunologic signaling pathways involving B cell activation and class-switch recombination reference contributions from laboratories at the NIH, Stanford University, University of Oxford, University of Cambridge, and Kyoto University. Clinical immunodeficiency contexts involve centers such as Great Ormond Street Hospital, Mayo Clinic, Cleveland Clinic, Mount Sinai Health System, and Karolinska University Hospital.

Clinical Significance and Diseases

IgA deficiency and dysregulation are implicated in conditions managed by specialists from hospitals including Massachusetts General Hospital, Guy’s and St Thomas’ NHS Foundation Trust, and University Hospital Zurich, and in diseases such as selective IgA deficiency, IgA nephropathy, Henoch–Schönlein purpura, celiac disease, inflammatory bowel disease, chronic obstructive pulmonary disease, and recurrent respiratory infections documented in cohorts from Imperial College London, University of Pennsylvania, and University of California, San Francisco. Pathology described in nephrology literature from the American Society of Nephrology, European Renal Association–European Dialysis and Transplant Association, and the International Society of Nephrology includes mesangial deposition characterized in landmark series from Mount Sinai School of Medicine and University of Toronto. Vaccine responses, allergy and atopy links are examined in trials coordinated by the Vaccine Research Center, Gavi, the Vaccine Alliance, and the Bill & Melinda Gates Foundation.

Diagnostic Measurement and Laboratory Testing

Quantification and characterization of IgA use techniques developed at institutions such as the Mayo Clinic, Cleveland Clinic, and Johns Hopkins Hospital, including ELISA platforms refined at Stanford University, flow cytometry protocols from the La Jolla Institute for Immunology, nephelometry and turbidimetry used in clinical laboratories at University College London Hospitals and University Hospital Heidelberg, and mass spectrometry workflows from the Max Planck Institute and Scripps Research. Reference ranges and clinical thresholds derive from population studies by the Framingham Heart Study, the UK Biobank, the National Health and Nutrition Examination Survey, and cohort studies at Karolinska Institutet and the University of Gothenburg. International laboratory standards and quality control are coordinated by organizations like the International Organization for Standardization, Clinical and Laboratory Standards Institute, and the College of American Pathologists.

Therapeutic and Research Applications

Therapeutic strategies targeting IgA pathways involve monoclonal antibodies, mucosal vaccines, and engineered secretory components developed in biotech firms and academic spin-outs from institutions like Genentech, Regeneron, Moderna, and AstraZeneca, and tested in clinical trials at the National Institutes of Health Clinical Center, Mayo Clinic, and Cleveland Clinic. Research on IgA monoclonal therapeutics cites translational work from the Fred Hutchinson Cancer Center, Dana–Farber Cancer Institute, Memorial Sloan Kettering Cancer Center, and the Ludwig Institute for Cancer Research. Microbiome therapeutics, passive immunization with dimeric IgA, and gene‑editing approaches referencing CRISPR research from the Broad Institute, University of California, Berkeley, and MIT are under investigation in collaborations involving the Wellcome Trust and the Gates Foundation. Ongoing global consortia include partnerships between the World Health Organization, Coalition for Epidemic Preparedness Innovations, and national research agencies.

Category:Antibodies