What component triggers the immune response in celiac disease?

What component triggers the immune response in celiac disease?

• A. Dairy
• B. Bacterial infection
• C. Glutenin
• D. Gliadin

Answer: (D)

In celiac disease, the immune response is triggered by a protein component of gluten called gliadin. Gluten is a mixture of gliadin and glutenin, but gliadin is the part that is most immunogenic in people who are genetically susceptible. When gliadin peptides are ingested, they cross the intestinal lining and are deamidated by tissue transglutaminase, which increases their binding to HLA-DQ2 or HLA-DQ8 molecules on antigen-presenting cells. This presents gliadin to CD4+ T cells, activating them and releasing inflammatory signals that damage the small-intestinal mucosa, leading to villous atrophy and malabsorption. Antibodies to tissue transglutaminase can be produced as part of the broader immune response, but the initiating trigger remains gliadin.

In celiac disease, the immune response is triggered by a protein component of gluten called gliadin. Gluten is a mixture of gliadin and glutenin, but gliadin is the part that is most immunogenic in people who are genetically susceptible. When gliadin peptides are ingested, they cross the intestinal lining and are deamidated by tissue transglutaminase, which increases their binding to HLA-DQ2 or HLA-DQ8 molecules on antigen-presenting cells. This presents gliadin to CD4+ T cells, activating them and releasing inflammatory signals that damage the small-intestinal mucosa, leading to villous atrophy and malabsorption. Antibodies to tissue transglutaminase can be produced as part of the broader immune response, but the initiating trigger remains gliadin.