New York, September 15, 1998 -- Over the past decade, knowledge about how the immune system can be used to fight cancer has greatly increased. Not only have scientists learned that the immune system can recognize certain proteins on cancer cells, but they have used this knowledge to develop vaccines that may help to prevent cancer recurrence.

Now, scientists at Memorial Sloan-Kettering Cancer Center in New York have shown that a new DNA-based vaccine can successfully treat the deadly skin cancer, melanoma, in mice. The investigators, who report their findings in the September 15 issue of the Journal of Clinical Investigation, used a "needleless syringe" called a gene gun to drive tiny particles of human DNA at high speed into the mice's skin. The human protein differed just enough from its mouse counterpart to trick the immune system into producing a powerful immune attack. The immune cells attacked both the melanoma cells and the pigment cells in the skin of the mice, which share a protein called gp75 that is not found in other tissues.

"Our study shows how we can use DNA immunization to make the immune system recognize and attack cancer cells," said Dr. Alan Houghton, Chief of the Clinical Immunology Service at Memorial Sloan-Kettering and senior author of the study. The same strategy is being tested against prostate, breast and lymphoma cancers in mice, as they also share specific proteins with their normal cell counterparts.

"These DNA vaccines are unique because they can trigger immunity where other types of vaccines can fail to stimulate an immune response," added Dr. Houghton, noting that they are easy to make, handle and store.

The mice were immunized with human DNA via a novel delivery system called a gene gun, in which microscopic gold particles were coated with the human DNA and injected into the mice's skin using a burst of helium gas. Once inside the sk
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Contact: Kelli Stauning
staunink@mskcc.org
(212) 639-3573
Memorial Sloan-Kettering Cancer Center
15-Sep-1998