Anti-transglutaminase antibodies antigen, presented by MHC molecules (HLA in humans) on antigen-reactive B-cells. These T-helper cells then stimulate B-cells to multiply and mature into plasma cells that make IgA and IgG to that protein. In the case of celiac disease, the current understanding is that tTG autoimmunity arises when T-cells are generated against wheat gliadin and similar gluten proteins made by a class of grasses called "Triticeae", which includes wheat (See Wheat taxonomy), barley, and rye. The T-cells are defined by the ability to react to HLA-DQ8 and DQ2.5 restricted antigens and gliadin is one of the antigens. Gliadin is a favored
Gluten immunochemistry its genome contains chromosomes derived from two goat grass species and a primitive wheat species. The positions of these motifs in different species, strains and isoforms may vary because of insertions and deletions in sequence. There are a large number of wheat variants, and a large number of gliadins in each variant, and thus many potential sites. These proteins once identified and sequenced can be surveyed by sequence homology searches. HLA-DQ recognition of gliadin is critical to the pathogenesis of gluten-sensitive enteropathy, it also appears to be involved in idiopathic gluten sensitivity (See:Understanding DQ Haplotypes and DQ isoforms on the