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
Wheat allergy high molecular weight glutenin subunit, and similar proteins in other "Triticeae" genera, enter the blood stream during exercise where they cause acute asthmatic or allergic reaction. One recent study of ω-gliadins demonstrated these gliadins are more similar to the bulk of oat avenins than α/β or γ gliadins but, so far, oat avenins have not been linked to WDEIA. Wheat may specifically induce WDEIA and certain chronic urticaria because the anti-gliadin IgE detects ω-gliadins expressed by most of the Gli-B1 alleles, but prolamins extracted from rye or wheat/rye translocates invoke almost no responses. The Gli-B1 gene in wheat, "Triticum aestivum",