Dendritic cells are cells whose role it is to process antigens and “present” them to T cells, which are a type of immune cell. Macrophages are another type of immune cell – namely, large white blood cells whose main role is to rid our bodies of debris and toxic substances.
The cell culture results – which the researchers then verified in mouse models – showed that once PVS-RIPO infects the dendritic cells, these cells “tell” T cells to start the immune attack.
Once started, this process seems to be continuously successful. The cancer cells continue to be vulnerable to the immune system’s attack over a longer period of time, which appears to stop the tumor from regrowing.
As Prof. Nair explains, “Not only is poliovirus killing tumor cells, it is also infecting the antigen-presenting cells, which allows them to function in such a way that they can now raise a T cell response that can recognize and infiltrate a tumor.”
“This is an encouraging finding, because it means the poliovirus stimulates an innate inflammatory response.”
Prof. Smita Nair
Speaking to Medical News Today about the clinical implications of the findings and the scientists’ directions for future research, Dr. Gromeier said, “Our findings provide clear rationales for moving forward with clinical trials in breast cancer, prostate cancer, and malignant melanoma.”
“This includes novel combination treatments that we will pursue,” he added.
More specifically, he explains, because the study revealed that after treatment with the poliovirus “immune checkpoints are increased on immune cells,” a future strategy the researchers plan to explore is “[oncolytic] poliovirus combined with immune checkpoint blockade.”