Biochemical modifications of gliadins induced by microbial transglutaminase on wheat flour.

BACKGROUND: Celiac disease (CD) is an immune-mediated disorder caused by the ingestion of wheat gluten. A lifelong, gluten-free diet is required to normalize the intestinal mucosa. We previously found that transamidation by microbial transglutaminase (mTGase) suppressed the gliadin-specific immune response in intestinal T-cell lines from CD patients and in models of gluten sensitivity. METHODS: SDS-PAGE, Western blot, ELISA, tissue transglutaminase (tTGase) assay and nano-HPLC-ESI-MS/MS experiments were used to analyze prolamins isolated from treated wheat flour. RESULTS: Gliadin and glutenin yields decreased to 7.6±0.5% and 7.5±0.3%, respectively, after a two-step transamidation reaction that produced a water-soluble protein fraction (spf). SDS-PAGE, Western blot and ELISA analyses confirmed the loss of immune cross-reactivity with anti-native gliadin antibodies in residual transamidated gliadins (K-gliadins) and spf as well as the occurrence of neo-epitopes. Nano-HPLC-ESI-MS/MS experiments identified some native and transamidated forms of celiacogenic peptides including p31-49 and confirmed that mTGase had similar stereo-specificity of tTGase. Those peptides resulted to be 100% and 57% modified in spf and K-gliadins, respectively. In particular, following transamidation p31-49 lost its ability to increase tTGase activity in Caco-2 cells. Finally, bread manufactured with transamidated flour had only minor changes in baking characteristics. CONCLUSIONS: The two-step transamidation reaction modified the analyzed gliadin peptides, which are known to trigger CD, without influencing main technological properties. GENERAL SIGNIFICANCE: Our data shed further light on a detoxification strategy alternative to the gluten free diet and may have important implications for the management of CD patients.

Application of egg-yolk-antibody to prevent recolonization of Streptococcus mutans / 实用口腔医学杂志

Objective:To investigate the effect of local application of the water soluble protein fraction,containing specific egg yolk antibody,on the recolonization of Streptococcus mutans.Methods:Whole cells of inactivated streptococcus mutans were used as antigen to immunize bens,then water soluble protein fraction(WSF) was extracted from the eggs. Mouth wash containing 0.1 mg/ml of WSF was prepared and administered to 8 volunteers.The mouth wash was used once every two days for 2 weeks.Vehicle solution was used in other 6 volunteers as the control.S.mutans in saliva was monitored for 100 days.Results:Before using the mouth washes,S.mutans level in saliva of the volunteers was 36.4%.S.mutans was removed by hibitane,it kept less than 3% in 100 days in the tested individuals,while 23%～37% in the controls.Conclusion:The WSF containing specific egg yolk antibody can effectively prevent the recolonization of streptococcus mutans.