Researchers at the University of California, San Diego have discovered a plant virus that effectively activates the immune system to attack cancer cells. The cowpea mosaic virus (CPMV) triggers both innate and adaptive immune pathways, priming the immune system to recognize and fight cancer cells. This finding has significant implications for cancer immunotherapy.
According to senior author Nicole Steinmetz, PhD, CPMV stimulates an anti-tumor response by drawing in multiple types of immune cells and activating B and T cells. The virus also triggers the production of type I, II, and III interferons, which have known anti-cancer properties. In contrast, a closely related virus, cowpea chlorotic mottle virus (CCMV), failed to produce effective tumor clearance.
The researchers used various techniques to study the mechanism of action of CPMV, including immune-multiplexing, cellular trafficking assays, and cytokine profiling. They found that CPMV’s RNA persists longer within immune cells and is delivered to the endolysosome, where it activates Toll-like receptor 7 (TLR7). This receptor is essential for triggering antiviral and anti-tumor responses.
The study demonstrates that CPMV has tumor-agnostic efficacy in multiple mouse models and can inhibit tumor-promoting signals. The researchers also found that CPMV is recognized as a foreign pathogen through pattern recognition receptors, resulting in a cascade of immune activity. The study’s findings are promising, but require further validation in human systems.
The researchers emphasize the importance of characterizing systemic effects, determining safety profiles, and selecting the most effective viral constructs for clinical use. They believe that leveraging the breadth of pathogens found across different kingdoms could lead to new therapies.
Overall, this study provides important insights into the mechanism of action of CPMV and its potential as a cancer immunotherapeutic agent. The researchers are now refining their formulation, dosage, and treatment protocols in preparation for early-phase clinical trials.
Source: https://www.insideprecisionmedicine.com/topics/oncology/plant-virus-reprograms-immune-system-to-fight-cancer