According to researchers, a cancer vaccination could improve the immune response of T cells and help shrink existing tumors.
For the past decade, scientists have been exploring vaccination as a method for fighting cancer. MIT postdoctoral researcher Megan Burger is the lead author of a new study published in the journal Cell. Researchers found during the clinical trial in mice that vaccines boost the overall T-cell response and help shrink the tumor.
Vaccination against cancer: Not only for prevention, but also as therapy
“This study highlights the importance of detailed research into the immune response against cancer. We discovered that not all anti-cancer immune responses are generated equally. Vaccination can unleash a potential response.”
When cells become cancerous, they begin to produce mutated proteins that are not found in healthy cells. Thanks to these proteins, the tumor creates an immunosuppressive environment that deactivates the T cells and can therefore grow unchecked. The researchers hope that the vaccines can regenerate the T cells, allowing them to attack the tumor. They developed methods to identify the neoantigens in patients' tumors and incorporate them into individualized vaccines. Such vaccines have shown promise in clinical trials in treating melanoma and non-small cell lung cancer.
“The treatment works amazingly for a small proportion of patients, but the majority do not respond. “We’re trying to understand why that is and what we can do to get more patients to respond,” Burger said. Previous studies showed that only a few of the hundreds of neoantigens in the tumors produce a response.The new studyhas shown in mice with lung cancer that subsets of T cells that fight different cancer proteins compete with each other. This leads to the formation of a dominant T cell population that only responds to one neoantigen and suppresses the other T cells. Burger discovered that vaccination with a different neoantigen can regenerate the suppressed T cells. Identifying suppressed responses can improve patient response. The best results have been achieved when vaccinating with neoantigens that are weakly bound to the immune cells, which then deliver them to the T cells. The lung tumors of the mice vaccinated in this way shrank by 27%. After vaccination, the T cell population also has the opportunity to constantly renew the response. In their further work, the researchers hope to combine the vaccines with medicines.
