PHILADELPHIA--Last year, David Berd, an oncologist at Thomas Jefferson University here, found that melanoma patients given an injection of altered versions of their own tumor cells after surgery were nearly twice as likely to remain tumor-free as were patients given surgery alone. Now Berd has shown that his novel preparation appears to trigger a heightened immune response. The finding, reported in the current issue of the Journal of Clinical Investigation, is the first evidence that this avant-garde cancer therapy acts like a vaccine on the cellular level.
Berd and colleagues at the National Institute of Tumors in Milan, Italy, treated melanoma cells drawn from six patients with dinitrophenyl, a chemical that binds to the cells and serves as a red flag for the immune system. The treated tumor cells, deactivated by radiation, are designed to trigger the production of novel T cells, which could be called on to thwart a recurrence of melanoma.
The group injected the altered cells back into the patients, who were recovering from surgery to remove melanoma lesions. The preparation did indeed provoke a heightened immune response: Blood samples from five of the six patients had increased levels of T cells, a type of white blood cell that attacks the tumor cells. "These were not just any old T cells, but particular clones of T cells that had been elicited by the vaccine," Berd says.
Part of what makes the vaccine so ingenious, says Pramod Srivastava, an immunologist at the University of Connecticut, Farmington, is that it's customized for each patient. Berd is "doing something very difficult, but something that's very appropriate."