A team of Duke University researchers has created an antibody from the human body's own immune system that targets cancer cells by setting its sights on a natural defense mechanism that cancer tumors exploit. The new antibody was discovered, developed and tested in both cell lines and animal models.
The cells that make up the human body utilize a security system that uses specific proteins to protect the cell surface through the prevention of injury and death from harmful activation of the immune system. Using the cancer-fighting antibody that they discovered, the team found that it can take down a part of cancer cell's defense system and subsequently attack it.
"This is the first completely human-derived antibody developed as an anti-cancer therapy, which is very different from other immunotherapy approaches," said Edward Patz, Jr., professor at Duke University and senior author of the study.
Patz and his team first examined the presence of early-stage tumors in lung cancer patients that never progress. The team noticed that when compared to those with more lethal tumors, these patients possessed antibodies against a protein called complement factor H (CFH), a protein that guards cells against an attack from the immune system.
CFH inhibits the deposit of a complement C3b protein on the cell surface, an important immune response that causes degradation of the cell membrane and, eventually, cell death.
After identifying the antibody for CBH, Patz and his team developed mature forms of it that were able to attack cancer cells and avoid targeting healthy cells. They tested this antibody in numerous cancer cell lines, as well as tumors in living mice, and found that they caused tumor cell death without any noticeable side effects. Furthermore, they triggered an adaptive immune response that lead to a systemic attack.
"We believe it might be this additional cellular response that could potentially have the most profound impact on cancer outcomes long-term," Patz said, although he acknowledged that further research is needed to better understand the approach.
"This could represent a whole new approach to treating cancer, and it's exciting because the antibody selectively kills tumor cells, so we don't have significant side effects to achieve tumor control," he added. "We believe we can modulate the immune response and let the body's own immune system take over to either kill the tumor or keep it from growing."
The findings were published in the May 5 issue of the journal Cell Reports.