The Duke researchers have devised a way to engineer dendritic cells to display tumor antigens. Now they are testing whether these cells will signal an effective immune response. They reasoned that the best way to get cancer antigens into dendritic cells is to have those proteins produced within the dendritic cell itself. To do this they isolate and remove RNA from tumor cells and infuse it into dendritic cells. RNA thus "transfected" into a host cell uses that cell's machinery to make tumor proteins, which are then chopped up and displayed on the cell surface.

Mass quantities of the vaccine can be produced for each patient using a special cell processing laboratory. The vaccine is then injected into the patient to elicit an immune system against cancer in their body.

Using a patient's own RNA to produce red-flag antigens leaps a major hurdle that has halted other attempts at devising an effective and widely applicable cancer vaccine, Gilboa said. It produces antigens that are specific to that individual's cancer. Many cancer immunotherapies may fail because they rely upon a single specific protein antigen that may or may not be found in that patient's tumor cells, Gilboa said. "It's difficult to find a protein fragment that works well for all patients, so the idea is to have a patient's own RNA make its cancer antigens."

In some vaccine trials, researchers have had to isolate antigens directly from tumors of cancer patients ? which is expensive and problematic, Gilboa said. This new strategy allows large quantities of vaccine to be produced from a small amount of tumor taken from a patient. Duke researchers have the technology to isolate dendritic cells from blood and then
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Contact: Renee Twombly
twomb001@mc.duke.edu
919-684-4148
Duke University Medical Center
26-Mar-1998