T lymphocytes of the immune system are vital to bodily defenses against viruses and cancer. T lymphocytes are activated in part by molecules called co-stimulatory signals, of which 4-1BB is one example. However, tumor cells are cleverly able to turn off the effects of some co-stimulatory molecules, thus ensuring their own survival.
Recent experiments in mice have shown that binding a monoclonal antibody to 4-1BB activates this co-stimulatory molecule and triggers a strong immune response. Based on this knowledge, Karl Erik Hellstrom and colleagues at the Pacific Northwest Research Institute in Seattle have developed a form of gene therapy to treat cancer (Nature Medicine, Vol. 8, No. 4, 01 Apr 02, p. 343). They inserted a gene for a fragment of the antibody to 4-1BB into mouse melanoma cells and used these ‘transfected’ cells to vaccinate other mice. The inoculation stimulated the immune system against cancer cells and vaccinated mice were able to reject other tumors. Lieping Chen of the Mayo Clinic discusses the potential of this gene therapy vaccine to treat human cancers (p. 333). Dr. Karl E. Hellström Pacific Northwest Research Institute 720 Broadway Seattle, WA 98122 Tel: +1 206 726 8747 Fax: +1 206 860 6773 Email: khellstrom@pnri.org Dr. Lieping Chen Department of Immunology Mayo Clinic 200 First St, SW Guggenheim 342B Rochester, MN 55905 Tel: +1 507 538 0013 Fax: +1 507 284 1637 Email Address: chen.lieping@mayo.edu (C) Nature Medicine press release.
Message posted by: Trevor M. D'Souza
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