Researchers close in on breast canc...( Progress toward development of a breast...),Health

Cancer-fighting vaccines stimulate immune cells to recognize tumor cells as foreign and destroy them. Physicians believe a vaccine-induced immune response could be used to supplement other cancer therapies or to immunize high-risk people against cancer.

"We've been studying a protein called mammaglobin-A found in 80 percent of breast tumors," says Thalachallour Mohanakumar, Ph.D., the Jacqueline G. and William E. Maritz Professor of Immunology and Oncology in the Department of Surgery and at the Siteman Cancer Center. "The protein is especially interesting for cancer immunotherapy because of its frequent occurrence and because breast tumors express it at high levels."

In articles in the Journal of the National Cancer Institute and Breast Cancer Research and Treatment, the researchers report that they constructed a vaccine consisting of copies of the DNA sequence that makes mammaglobin-A in humans.

The researchers theorized the DNA vaccine would rev up special immune cells called T cells to recognize mammaglobin-A as a foreign molecule when it is displayed on the surface of cells as an antigen (a small protein that the immune system may recognize). The primed T-cells then would proliferate and attack when they met with mammaglobin-A antigens.

"Mammaglobin-A is involved in breast development and secreted in breast milk," Mohanakumar says. "So we had to prove first that we could elicit an immune response to a protein that is in the body normally."

They injected the DNA vaccine under the skin of test mice that had been engineered so that their immune systems would react to the human mammaglobin-A like a human immune system. The researchers loaded specific cells in the mice with mammaglobin-A antigens and found that the vaccine-prime
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Contact: Gwen Ericson
jdryden@wustl.edu
314-286-0141
Washington University School of Medicine
8-Mar-2005