New Approach to Cancer Immunotherapy Developed

Newswise — A novel new cancer treatment has been shown to eliminate or shrink tumors in 100 mice. The treatment causes anti-viral T cells " white blood cells that play a large role in the body's immune response " to recognize tumors as virus-infected cells, and thus attack them. The Technion " Israel Institute of Technology study is published in the June 15, 2004 Proceedings of the National Academy of Sciences.

"Our approach is to use anti-viral T cells to kill tumors," says Dr. Yoram Reiter of the Technion Faculty of Biology. "Tumor-specific T cells are very rare and not very efficient. On the other hand, the body has very efficient anti-viral T cells, because throughout our lives we're exposed to many viruses such as influenza. These cells are very efficient at recognizing cells that don't belong."

Says Dr. Andrew Simpson of the Ludwig Institute for Cancer Research in New York: "The approach developed by Dr. Reiter and his colleagues is a significant new approach to cancer immunotherapy. Coupling the specificity of antibody targeting and the selective toxicity of T cells in this way will make it much harder for tumor cells to escape targeting by the immune system."

The team genetically engineered a molecule that is naturally found in the body. On one side of the molecule is an antibody designed to attach itself to a specific type of cancer cell. On the other side, the team placed a molecule called major histocompatability complex (MHC) that allows T cells to recognize if the cells are 'self' or 'foreign.' MHC does this through its peptides, small fragments of protein from cells. T cells survey peptides on MHC molecules to determine whether the cells attached to the MHC molecules are foreign and should be destroyed.

The team places peptides on the molecule that tell T cells that tumors are actually virus-infected cells, so anti-viral T cells now target and kill what they believe to be a virus-infected cell.

This process can be designed for any type of tumor, and to attract any type of anti-viral T cell. Over the past two years, the researchers have conducted test tube and animal experiments, shrinking or eliminating tumors in mice that replicate human cancers such as breast cancer and leukemia.

Reiter cautions that many approaches in cancer research have been successful in mice but do not translate to humans. He remains optimistic, however, and strongly believes the process will not be toxic " unlike chemotherapy and similar treatments " since it is based on natural molecules in the immune system.

The Technion-Israel Institute of Technology is Israel's leading science and technology university. It commands a worldwide reputation for its pioneering work in computer science, biotechnology, water-resource management, materials engineering, aerospace and medicine. The majority of the founders and managers of Israel's high-tech companies are alumni. Based in New York City, the American Technion Society is the leading American organization supporting higher education in Israel, with more than 20,000 supporters and 17 offices around the country.