Apr. 17, 2007 Active immunisation can stimulate the body to produce highly efficient IgE antibodies that attack tumours. This breakthrough, achieved in an animal model, is based on the skillful combination of two established experimental methods. The results are now being published in Cancer Research and are part of a project funded by the Austrian Science Fund FWF. The antibodies produced during the project belong to a class that also plays a key role in the development of allergic reactions.
People who suffer from allergies are well acquainted with immunoglobulin E (IgE). It is this class of antibodies that plays a key role in causing an allergy sufferer's immune system to overreact. Oncologists too are very familiar with IgE. Numerous in-depth studies have shown that those with raised levels of IgE are much less likely to suffer from certain types of cancer. Or in other words - allergy sufferers are at a lower risk of developing cancer.
Allergy & Cancer
"In actual fact, the IgE produced during an allergic reaction does not attack cancer tumours but instead attacks allergens, for example pollen," explains the study's leader, Prof. Erika Jensen-Jarolim, head of the Department of Pathophysiology at the Medical University of Vienna. "The fact that IgE nevertheless acts against tumours is more of a fortunate side-effect of the highly efficient characteristic of this antibody class. It was our aim to make this antibody class, which is typical for allergies, act directly against tumours. At the same time, we wanted to encourage the long-term production of IgE in the body by means of active immunisation."
Prof. Jensen-Jarolim's group recently succeeded in achieving the latter - active immunisation against certain types of tumour - in mice. However, due to the selected type of immunisation (injection below the abdominal wall) the antibodies that were produced belonged to the IgG class. This type of antibody produces a much more limited and shorter-term effect against tumours than IgE antibodies.
Through the Stomach
Prof. Jensen-Jarolim used one of her group's earlier successes - achieved as part of another FWF project on food allergies - to ensure that immunisation resulted in the intended activation of IgE. These findings prove that food proteins are effective in inducing IgE-dependent immune reactions when they withstand the acidic environment of the stomach.
Prof. Jensen-Jarolim's team therefore fed mice a peptide very similar to a tumour peptide while reducing acidification in the stomach, thereby hindering digestion of the peptide. As a result, a type of allergic reaction was triggered against this tumour-like peptide - the mice produced tumour-specific IgE antibodies. The result is the world's first active IgE-stimulating tumour vaccination.
Reference: Active Induction of Tumor-Specific IgE Antibodies by Oral Mimotope Vaccination. Angelika B. Riemer, Eva Untersmayr, Regina Knittelfelder, Albert Duschl, Hubert Pehamberger, Christoph C. Zielinski, Otto Scheiner and Erika Jensen-Jarolim. Cancer Research, doi: 10.1158/0008-5472.CAN-06-3758
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