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
Rye bread upon this mixing of grains. Use of high-gluten wheat flour also makes possible multigrain breads, such as the "rye and Indian" bread of the American colonies, which combined rye and wheat with cornmeal in one loaf. Rye bread contains phenolic acids and ferulic acid dehydrodimers. Pure rye bread contains only rye flour, without any wheat. German-style pumpernickel, a dark, dense, and close-textured loaf, is made from crushed or ground whole rye grains, usually without wheat flour, baked for long periods at low temperature in a covered tin. Rye and wheat flours are often used to produce a rye bread with