The immune system is comprised of various cells that work in concert to fight off disease. The two immune responses, innate and adaptive, are orchestrated to build a specific reaction to the invading pathogen. Dendritic cells are what connect the two responses. Specifically, dendritic cells will take proteins from the infected cells and present that piece of protein or antigen outside its surface. The expressed antigen is then detected by T cells, which are responsible for eliminating pathogens. As a result, dendritic cells activate T cells and prime them to target disease. The mechanism by which dendritic cells process and express proteins specific to infection for immune cell activation provides an understanding of the immune system and how to generate effective therapies.
Immunotherapies have revolutionized the way physicians treat cancer. In many cases, tumors use different traits and channels to go undetected by the immune system. Immunotherapy redirects the immune system to recognize and target the tumor. Many treatments are aimed at targeting T cells; however, other types of therapies are being tested to enhance efficacy through dendritic cells. It is believed that if dendritic cells can do a better job at presenting proteins specific to the cancer, then more T cells will be activated. Scientists are continuously working to improve current immunotherapies.
A recent article in Nature Communications, by Dr. David Sancho and others, found that a type 1 dendritic cell vaccine is critical in eliciting a robust immune response and leads to immune memory. Type 1 or conventional dendritic cells are known to regulate tumor growth at the primary site of cancer. Immune memory refers to the ability of T cells to remember foreign invaders after previously contacting pathogen. As the immune system works to rid the body of disease, some T cells become memory-like in which the body builds an immunity. Sancho is a lead scientist at the Spanish National Center for Cardiovascular Research (CNIC). His work focuses on immune cell trafficking and how to effectively elicit an immune response with immunotherapy. Specifically, Sancho has been recognized internationally for his work on T cell priming.
Sancho and his team used models that mimic human cancer to test a dendritic cell vaccine. As a result, T cells were activated, and tumors significantly shrunk. When researchers injected previously vaccinated mice with a second tumor, tumors did not grow. Further investigation determined that memory T cells were increased. To improve the rigor of their work, researchers tested their findings in a few different cancer models including breast cancer and melanoma.
The discovery made by Sancho and others outlines the importance of dendritic cells in the immune response and vaccine technology. Their work has provided an alternative immunotherapy regimen that could be combined or added to standard-of-care for effective outcomes. Additionally, their work has the potential to improve treatment efficacy through vaccination in patients with resected tumors. Further investigation is needed before therapy can move into clinical trials. However, Sancho’s work highlights a key limitation in the current field of cancer treatment: dendritic cells can often be overlooked when developing immunotherapies. Overall, this work could improve long-term survival in patients with hard-to-treat tumors.