Part of what makes treating cancer so tricky is that cancer cells are just normal cells that have gone haywire. It is sometimes hard for the body to recognize these aberrant cells to dispose of them via the immune system, and it is also hard to design drugs that can effectively kill the cells, while leaving healthy cells alone. A new paper published in Nature Biotechnology from senior author David Mooney of Harvard University describes a new vaccine that is able to self-assemble into a 3D structure and manipulate immune cells, teaching them to attack cancer as well as infectious disease.

"This vaccine is a wonderful example of applying biomaterials to new questions and issues in medicine," Mooney said in a press release.

The vaccine is composed of nanoscale silica rods, which are administered via injection. Once inside the body, the rods group together into a scaffold-like structure. This structure is then able to draw in immune cells and teach them how to take on threats to the body. Rather than introducing a weakened version of the disease in order to expose the immune system to it, this works on the immune cells directly.

Previous research used a dime-sized scaffold in mouse models, attempting to reprogram dendritic cells. These cells are responsible for locating specific antigens on the surface of cancer cells, and then calling in an attack if they find anything that needs to be eliminated. This vaccine was successful in slowing down tumor progression in the mice, and 90% of them outlived control mice who did not receive the cell reprogramming.

In the current paper, the scaffold was deconstructed into the vaccine, and spontaneously assembled once inside the organism. Two groups of mice with lymphoma received either the scaffold vaccine or a traditional bolus injection that just exposed the immune system to the antigens and medications. At the end of 30 days, 60% of the mice who received the bolus injection were still alive, while 90% of the mice who received the scaffold vaccine lived.

"The ability to so elegantly harness the natural behavior of dendritic cells to elicit a strong immune response is impressive," added Jessica Tucker from the National Institute of Biomedical Imaging and Bioengineering, which funded the study. "The possibility of developing this approach as a cancer vaccine, which would not require an invasive and costly surgery to manipulate immune cells outside of the body, is very exciting.”

Moving forward, the researchers would like to expand upon this approach and make it available to treat a wide variety of diseases. Rather than building a scaffold which can train dendritic cells to identify certain cancers, it would also teach the cells how to identify infectious diseases.

"I think this is going to be the first of a number of examples where we utilize ideas of self-organization in the body instead of having to create structures outside of the body and place them in," Mooney concluded. "I think that will be broadly applicable, not only in instances like this, but also, for example, in tissue engineering and regenerative medicine where scaffolds are used to facilitate the regrowth of tissues in the body. The ability to assemble a scaffold in the body instead of having to surgically implant it would be a significant advance.”