Toxicity of bread wheat lines lacking prolamins encoded by the Gli-B1/Gli-B5/Glu-B3 and Gli-D1/Glu-D3 loci in coeliac disease as determined by their agglutinating activity

By De Vincenzi, M. - Dessi, M.R. - Luchetti, R. - Pogna, N. - Redaelli, R. - Galterio, G.

Peptic-tryptic (PT) digests of alcohol-soluble proteins from the flour of three mutant lines of bread wheat, lacking gamma-gliadins, omega-gliadins and low molecular-weight glutenin subunits encoded by the Cli-B1/Gli-B5/Glu-B3 loci (line S. Pastore 4A), the Gli-D1/Glu-D3 loci (line Alpe 1 I-) or both groups of loci (line DM 22166), were compared with those of the normal cultivars S. Pastore and Alpe 1 I for their agglutinating activities on human myelogenous leukemia K562(S) cells, agglutination being strongly associated with toxicity for the coeliac intestine. All of the genotypes tested contained A-type alpha-gliadins, which constituted about 19% of the gliadins in the S. Pastore and Alpe 1 I cultivars, 24.5%, in the S. Pastore 4A and Alpe 1 I- null lines, and 34.8% in the double mutant line, DM 22166, as determined by densitometric scanning of their acid polyacrylamide gel electrophoresis patterns. The minimal concentrations of PT digest required to agglutinate 100% of K562(S) cells were 73 mg/l and 96 mg/l in the S. Pastore and Alpe 1 I cultivars, respectively, compared with 146 mg/1, 138 mg/l and 200 mg/l in the "null" lines, S. Pastore 4A Alpe 1 I- and DM 22166, respectively. The results implicated that proteins other than alpha-gliadins are involved in the gluten-sensitive enteropathy.