Immune Cells May Help Deliver Cancer Vaccines for Children; Cell Culture Research Could Tap Potential of Immune System in Fighting Cancer

05/5/2003

SEATTLE, May 5 /PRNewswire/ -- In a finding that could lay the groundwork for future cancer vaccines for children, cancer researchers working in cell culture have shown that modified immune cells can efficiently deliver genetic material to stimulate a desirable immune response.

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 dendritic cells and CD40-B cells are antigen-presenting cells, whose function is to bring microorganisms and cancer cells to the attention of the body's immune system.

The finding reported today does not yet have an immediate clinical application. "What we know now is that we may have found a useful delivery system for the time when cancer vaccines are tested in children," said Dr. Coughlin, who is a research fellow from The Children's Hospital of Philadelphia, working in the laboratory of Robert H. Vonderheide, M.D., D.Phil., of Penn's Abramson Family Cancer Research Institute.

Pediatric oncologist Stephan A. Grupp, M.D., Ph.D., director of Stem Cell Biology at The Children's Hospital of Philadelphia, was the third member of the research team. "Our current work may eventually support immune-boosting therapies against pediatric cancers, such as neuroblastoma," said Dr. Grupp. Neuroblastoma, a solid tumor of the peripheral nervous system, accounts for 10 percent of all childhood cancers. It is a major research focus of the Oncology Program at Children's Hospital, one of the largest pediatric cancer programs in the United States.

Founded in 1855 as the nation's first pediatric hospital, The Children's Hospital of Philadelphia is ranked today as the best pediatric hospital in the nation by a comprehensive Child magazine survey. Through its long-standing commitment to providing exceptional patient care, training new generations of pediatric healthcare professionals and pioneering major research initiatives, Children's Hospital has fostered many discoveries that have benefited children worldwide. Its pediatric research program is among the largest in the country, ranking second in National Institutes of Health funding. In addition, its unique family-centered care and public service programs have brought the 381- bed hospital recognition as a leading advocate for children and adolescents from before birth through age 19. For more information, visit http://www.chop.edu. Established in 1997, the Abramson Family Cancer Research Institute integrates innovative cancer research, education, and patient care at the Abramson Cancer Center of the University of Pennsylvania. The Institute strives to accelerate the translation of laboratory discoveries into clinical treatments. The Abramson Cancer Center was among the first in the nation to become an NCI-designated Comprehensive Cancer Center. For more information on research at the Abramson Family Cancer Institute, visit http://www.uphs.upenn.edu/abramson. For cancer information written for patients by specialists at the Abramson Cancer Center, visit http://www.oncolink.com.

CONTACT: John Ascenzi, The Children's Hospital of Philadelphia, +1-215-590-7332, Ascenzi@email.chop.edu; or Greg Lester, University of Pennsylvania School of Medicine, +1-215-349-5658, Gregory.Lester@uphs.upenn.edu.