No significant difference in antigenicity or tissue transglutaminase substrate specificity of Irish and US wheat gliadins

The prevalence of clinical celiac disease has been shown to vary both acros s time and between genetically similar populations. Differences in wheat an tigenicity and transglutaminase substrate properties are a possible explana tion for these differences. This study assessed the antigenicity and transg lutaminase substrate specificities of gliadins from regions of high and low celiac disease prevalence. Gliadin was extracted from three commercial US wheat sources and two Irish sources. SDS-PAGE and western blotting revealed minor, but significant variations in the gliadin extracts. However, ELISA showed no difference in the antigenicity of these gliadins. Transglutaminas e pretreatment of gliadin resulted in no significant change in gliadin anti genicity and kinetic studies showed that the K(m)s of the various gliadins were very similar. Purified IgA and IgG had no effect on transglutaminase a ctivity. In summary, minor variations in wheat gliadins are unlikely to exp lain the observed differences in disease expression across genetically simi lar populations.