Surface Plasmon Resonance Technique Provides Rapid Profiling of Autoantibodies in Rheumatoid Arthritis

Using a new imaging technique, a fast and accurate profile of autoantibodies present in the blood serum of rheumatic patients can be made. This profile can give valuable information about the progress of the disease. A unique feature of this so-called surface plasmon resonance (SPR) technique is that it directly tests on blood serum, without complicated preprocessing.

Using SPR, a special chip will enable many parallel tests. Scientists from the University of Twente (Enschede, The Netherlands) and the Radboud University Nijmegen (The Netherlands) will publish data about the new imaging technique in an upcoming issue of the Journal of the American Chemical Society (JACS).

The investigators have run tests on the serum of 50 rheumatoid arthritis (RA) patients as well as a control group of 29 individuals. Direct testing on blood serum is unique: in other techniques, fluorescent labels and preprocessing is necessary to visualize the relevant proteins. The diluted serum is led over a special gold-coated microchip containing a large number of spots with a specific peptide coating. Whenever these peptides interact with autoantibodies present in the serum, this process can be monitored by SPR imaging. Using laser light, all gold spots are scanned: the reflection of light of the spots changes whenever there is a molecular interaction on the spot. At a certain angle of light, there is no reflection at all: this is the so-called SPR dip undergoing a shift caused by the interaction. The technique goes beyond establishing that autoantibodies are present: the interaction between the protein and the antibody can be monitored in real time and without any labels.

Autoantibodies are manufactured by the immune system as a reaction on the so-called citrullinated proteins playing a role in rheumatoid arthritis. On a single chip, several types of peptides can be placed, for rapid parallel screening. The next step will be, according to the scientists, to investigate in what way the patient profiles help to monitor the progress of the disease, which could lead to more customized treatments in the future. The applications are not limited to monitoring RA or other autoimmune diseases: SPR imaging can be used for monitoring a wide range of biomolecular interactions.


Related Links:
University of Twente
Radboud University Nijmegen