Scientists at Harvard University modified a commonly used polymer to train immune cells to respond effectively to cancer tumors in the body. By essentially implementing immunotherapy techniques in vivo using a safe polymer, the researchers achieved an increase from 0 to 90% in the survival of mice with melanoma.
MIT Technology Review reports:
First, it attracts dendritic cells by releasing a kind of chemical signal called a cytokine. Once the cells are there, they take up temporary residence inside spongelike holes within the polymer, allowing time for the cells to become highly active.
The polymer carries two signals that serve to activate dendritic cells. In addition to displaying cancer-specific antigens to train the dendritic cells, it is also covered with fragments of DNA, the sequence of which is typical of bacteria. When cells grab on to these fragments, they become highly activated. “This makes the cells think they’re in the midst of infection,” Mooney [David Mooney, professor of bioengineering at Harvard who leads the research project] explains. “Frequently, the things you can do to cells are transient–especially in cancer, where tumors prevent the immune system from generating a strong response.” This extra irritant was necessary to generate a strong response, the Harvard researchers found.
When implanted just under the skin of mice carrying a deadly form of melanoma, the polymer increased their survival rate to about 90 percent. By contrast, conventional immunotherapies that require treating the cells outside the body are 60 percent effective, says Mooney.
Abstract in Nature Materials…
Image: A polymer implant acts as an immune-cell training center. Immune cells lodge in its many holes and are exposed to chemical signals that encourage them to attack tumors. This image was made with a scanning electron microscope. Credit: Omar Ali