Article Text
Abstract
Background: It is now generally accepted that coeliac disease (CD) is caused by inflammatory T cell responses to gluten peptides bound to HLA-DQ2 or -DQ8 molecules. There is overwhelming evidence that CD patients can mount T cell responses to peptides found in both α-gliadin and γ-gliadin molecules. Assays that would detect the presence or absence of such peptides in food would thus be accurate indicators of safety for consumption by CD patients.
Aims: The development of a sensitive method to detect T cell stimulatory epitopes of α-gliadin and γ-gliadin molecules in food products.
Methods: Monoclonal antibodies (mAb) were raised against peptides encoding the T cell stimulatory epitopes of α-gliadin (amino acids (aa) 59–71) and aa γ-gliadin (aa 142–153 and aa 147–159). These mAb competition assays were developed that quantitatively detect T cell stimulatory epitopes present on both intact proteins and peptides of sizes recognisable by CD4+ T cells.
Results: With the mAb based competition assays, T cell epitopes were detected in pepsin/trypsin digests of wheat proteins and ethanol extracts of various food products, with detection levels lower than those reached with gluten specific T cells. Moreover, the presence of T cell stimulatory epitopes was also detected in preparations of barley, rye, and triticale, other cereals known to be toxic for CD patients.
Conclusions: A new antibody based method has been developed, detecting the presence of T cell stimulatory gluten peptides. This can be used to further ensure the safety of food consumed by CD patients.
- aa, amino acids
- HLA, human leucocyte antigen
- CD, coeliac disease
- mAb, monoclonal antibody
- tTG, tissue transglutaminase
- HMW, high molecular weight
- LMW, low molecular weight
- ppm, parts per million
- TTd, tetanus toxoid
- BSA, bovine serum albumin
- PBS, phosphate buffered saline
- TMB, 3,3′,5,5′-tetramethylbenzidine
- ELISA, enzyme linked immunosorbent assay
- SAMA, S-acetyl-mercaptoacetic acid
- coeliac disease
- T cell epitopes
- α-gliadin
- γ-gliadin
- monoclonal antibodies
- competition assay