A novel and sensitive method for the detection of T cell stimulatory epitopes of alpha/beta- and gamma-gliadin.

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 alpha-gliadin and gamma-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 alpha-gliadin and gamma-gliadin molecules in food products.

METHODS

Monoclonal antibodies (mAb) were raised against peptides encoding the T cell stimulatory epitopes of alpha-gliadin (amino acids (aa) 59-71) and aa gamma-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.