Original Paper

Plant Foods for Human Nutrition

, Volume 67, Issue 1, pp 24-30

Maize Prolamins Resistant to Peptic-tryptic Digestion Maintain Immune-recognition by IgA from Some Celiac Disease Patients

  • Francisco Cabrera-ChávezAffiliated withDipartimento di Scienze Molecolari Agroalimentari, Università degli Studi di Milano
  • , Stefania IamettiAffiliated withDipartimento di Scienze Molecolari Agroalimentari, Università degli Studi di Milano
  • , Matteo MirianiAffiliated withDipartimento di Scienze Molecolari Agroalimentari, Università degli Studi di Milano
  • , Ana M. Calderón de la BarcaAffiliated withCoordinación de Nutrición, Centro de Investigación en Alimentación y DesarrolloCentro de Investigación en Alimentación y Desarrollo Email author 
  • , Gianfranco MamoneAffiliated withIstituto di Scienze dell’Alimentazione, CNR
  • , Francesco BonomiAffiliated withDipartimento di Scienze Molecolari Agroalimentari, Università degli Studi di Milano

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Abstract

Maize is used as an alternative to wheat to elaborate foodstuffs for celiac patients in a gluten-free diet. However, some maize prolamins (zeins) contain amino acid sequences that resemble the wheat gluten immunodominant peptides and their integrity after gastrointestinal proteolysis is unknown. In this study, the celiac IgA-immunoreactivity to zeins from raw or nixtamalized grains, before and after peptic/tryptic digestion was evaluated and their possible immunogenicity was investigated by in silico methods. IgA from some celiac patients with HLA-DQ2 or DQ8 haplotypes recognized two alpha-zeins even after peptic/tryptic proteolysis. However, digestion affected zeins after denaturation, reduction, and alkylation, used for identification of prolamins as alpha-zein A20 and A30 by MS/MS sequencing. An in silico analysis indicated that other zeins contain similar sequences, or sequences that may bind even better to the HLA-DQ2/DQ8 molecules compared to the already identified ones. Results concur to indicate that relative abundance of these zeins, along with factors affecting their resistance to proteolysis, may be of paramount clinical relevance, and the use of maize in the formulation and preparation of gluten-free foods must be reevaluated in some cases of celiac disease.

Keywords

Celiac disease IgA-reactivity Zeins