The Prevalence of Anti-Zein Antibodies: A Comparative Study between Celiac Disease and Irritable Bowel Syndrome.

Celiac disease (CD) is a chronic immune-mediated enteropathy triggered by exposure to dietary gluten in genetically predisposed individuals. In contrast, irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder affecting the large intestine, without an autoimmune component. Here, we evaluated the prevalence of IgA and IgG antibodies to maize zeins (AZA) in patients with CD and IBS. Using an in-house ELISA assay, the IgA and IgG anti-zein antibodies in the serum of 37 newly diagnosed CD (16 biopsy proved and 21 serological diagnosis) and 375 IBS patients or 302 healthy control (HC) subjects were measured. Elevated levels of IgA AZA were found in CD patients compared with IBS patients (p < 0.01) and HC (p < 0.05). CD patients had the highest prevalence (35.1%), followed by IBS (4.3%) and HCs (2.3%) (p < 0.0001). IgG AZA antibodies were not found in any CD patients, IBS patients, or HC subjects. A significant positive correlation was found between IgA AZA with IgA anti-gliadin (AGA, r = 0.34, p < 0.01) and IgA anti-deaminated gliadin peptides (DGP, r = 0.42, p < 0.001) in the celiac disease group. Taken together, our results show for the first time a higher prevalence of AZA IgA antibodies in newly diagnosed CD patients than in IBS patients, confirming a biased immune response to other gliadin-related prolamins such as maize zeins in genetically susceptible individuals.

Indirect effects of immunological tolerance to a regular dietary protein reduce cutaneous scar formation.

Oral tolerance refers to the specific inhibition of immune responsiveness to T-cell-dependent antigens contacted through the oral route before parenteral immunization. Oral tolerance to one protein does not inhibit immune responses to other unrelated proteins, but parenteral injection of tolerated antigens plus adjuvant into tolerant, but not normal, mice inhibits immune responses to antigens injected concomitantly or soon thereafter. The inhibitory effect triggered by parenteral injection of tolerated proteins is known as bystander suppression or indirect effects of oral tolerance. Intraperitoneal injection of ovalbumin (OVA) plus alum adjuvant in OVA-tolerant mice soon before skin injury inhibits inflammation and improves cutaneous wound healing. However, as OVA is not a regular component of mouse chow, we tested whether indirect effects could be triggered by zein, the main protein of corn that is regularly present in mouse chow. We show that intraperitoneal injection of a single dose (10 µg) of zein plus alum adjuvant soon before skin injury in mice reduces leucocyte infiltration but increase the number of T cells and the expression of resistin-like molecule-α (a marker of alternatively activated macrophages) in the wound bed, increases the expression of transforming growth factor-ß3 in the newly formed epidermis and reduces cutaneous scar formation. These results suggest that indirect effects of oral tolerance triggered by parenteral injection of regular dietary components may be further explored as one alternative way to promote scarless wound healing.

Phylogenetic relationship of zeins and coixins as determined by immunological cross-reactivity and Southern blot analysis.

Zeins from Zea mays L cv. Maya and coixins from Coix lacryma-jobi L. cv. Adlay were fractionated to obtain alpha-, beta-, and gamma-zein and alpha-, beta-, and gamma-coixin. The alpha-coixins were composed of 4 polypeptide classes of 27 kDa (C1), 25 kDa (C2), 17 kDa (C4) and 15 kDa (C5) with solubility properties very similar to those of the 22 kDa and 19 kDa alpha-zeins. Like the alpha-zeins, the C1 and C2 alpha-coixins corresponded to 80% of total Coix prolamins. The fraction corresponding to gamma-coixin contained only one protein band of 22 kDa (C3). This coixin fraction has solubility properties similar to those of gamma-zein and represents 15% of the total coixin. The beta-zein fraction was composed of a major 17 kDa protein band, while the beta-coixin fraction consisted of a mixture of alpha- and gamma-coixins. Polyclonal antibodies raised against C1 recognized C1 and C2 and cross-reacted strongly with the 22 kDa alpha-zein, as did C4 and C5 antisera. The antiserum against gamma-coixin showed strong cross-reaction with gamma-zein. The homology between coixins and zeins was further investigated by using Southern hybridization analyses. The genomic DNA of maize and Coix were digested with several restriction enzymes and probed with cDNA clones representing 19 and 22 kDa alpha-zeins as well as the 28 and 16 kDa gamma-zeins. The Coix genome showed complex cross-hybridization sequences with the 22 kDa alpha-zein cDNA, while no cross-hybridization was observed with the 19 kDa cDNA clone.(ABSTRACT TRUNCATED AT 250 WORDS)