The alpha gliadins are a complex group of proteins with very similar sequences that comprise about 15-20% of the total flour protein and contribute to the functional properties of wheat flour dough. Some alpha gliadins also contain immunodominant epitopes relevant to celiac disease, a chronic autoimmune disease that affects nearly 1.4% of the worldwide population. In an attempt to reduce the immunogenic potential of wheat flour in the U.S. spring wheat cultivar Butte 86, RNA interference was used to silence a subset of alpha gliadin genes encoding proteins containing celiac disease epitopes. Two of the resulting transgenic lines were analyzed in detail by quantitative two-dimensional gel electrophoresis combined with tandem mass spectrometry. Although only some genes were targeted by the RNA interference construct, all alpha gliadins were effectively silenced in the transgenic plants. Some off-target silencing of high molecular weight glutenin subunits also was detected in both transgenic lines even though there was no homology with the target sequence. Reactivities of IgG and IgA serum antibodies from a cohort of patients with confirmed cases of celiac disease were decreased in flour from the two transgenic lines relative to the non-transgenic line. However, functional properties of the flour were also altered in the transgenic lines as evidenced by decreases in both mixing times and SDS sedimentation values. Although it may be possible to reduce the immunogenic potential of the flour and retain the viscoelastic properties essential for the utilization of wheat by eliminating only the most immunogenic alpha gliadins, the data suggest that it will be very difficult to selectively silence specific genes within families as complex as the wheat alpha gliadins.