Researchers from The Children's Hospital of Philadelphia and the Abramson Family Cancer Research Institute at the University of Pennsylvania manipulated immune cells called CD40-activated B cells to carry RNA produced by tumors and viruses. The RNA, which carries genetic codes from DNA, was obtained either from tumor or viral proteins. The researchers adapted an approach used in research on adults to one more appropriate for children.

The research team found that the B cells carrying the RNA "payloads" stimulated other blood cells to produce cytotoxic T lymphocytes: immune cells with the potential to kill invading cells. "This response could form the basis of a cancer vaccine that stimulates the body's existing immune system," said Christina M. Coughlin, M.D., Ph.D., who presented the research today at the annual conference of the Pediatric Academic Societies in Seattle.

Unlike routine childhood vaccinations such as those given to prevent the onset of infectious diseases such as polio or measles, cancer vaccines would be therapeutic vaccines, given to treat a disease that a patient already has.

Therapeutic cancer vaccines are currently being tested against a wide variety of malignancies, mostly in adult patients. Although none of these vaccines is yet approved by the U.S. Food and Drug Administration, one promising approach in adults uses dendritic cells extracted from the patient's own blood and formulated into a vaccine.

However, it has been technically difficult to retrieve sufficient dendritic cells from small children. Instead, the Philadelphia research team used CD40-B cells, which were extracted in small amounts from a child's blood, then grown in the laboratory. Both dendr
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4-May-2003