News Article

Tracking down autoantigens – new diagnostic method developed

The Department of Protein Science (PROT) has developed a new method of detecting autoantigens in active immune complexes with the aid of mass spectrometry. This will enable previously unknown disease-related immune targets to be identified. Moreover, this new technique will make it possible to create a timeline showing the formation of antigen-antibody complexes in autoimmune disease.

Working jointly with scientists from the Ludwig Maximilian University (LMU) in Munich, the team, headed by Dr. Stefanie Hauck and Dr. Juliane Merl (PROT), put this detection method to the test, taking as an example the autoimmune eye disease uveitis. In order to conduct mass spectrometric tests, which involve analyzing proteins in terms of their molecular size and sequences, they established an innovative method of preparing samples: the immune complexes are purified and then prepared by means of an organic precipitation reaction. This allows for the very sensitive detection of antigens, even in the tiniest concentrations of body fluids (below 1 femtomol/µl), the scientists report.

 “The mechanisms and autoantigens that trigger some autoimmune diseases are still not understood,” Dr. Hauck explains. “This is due primarily to a lack of suitable biochemical methods for examining proteins. Thanks to this new procedure, we can investigate autoreactive immune processes in various stages of a disease and characterize the structures that have been attacked.”

The results of this new method are published in the current edition of the Journal of Proteome Research.

Merl, J. et al. (2013). Identification of autoantigens in body fluids by combining pull-downs and organic precipitations of intact immune complexes with quantitative label-free mass spectrometry, Journal of Proteome Research, doi: 10.1021/pr4005986

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