Side-by-side illustration of the cowpea mosaic virus (CPMV, left), which has potent cancer-fighting effects, and the closely related cowpea cholorotic virus (CCMV, right), which does not exhibit anti-tumour effects.
In a study published in Cell Biomaterials, researchers led by chemical and nano engineers at the University of California San Diego investigated why the cowpea mosaic virus (CPMV), unlike other plant viruses, is uniquely effective at activating the immune system to attack cancer cells. The work, titled “Comparative analyses for plant virus-based cancer immunotherapy drug development”, sheds light on CPMV’s potent anti-tumour effects observed in multiple mouse models and canine cancer patients.
When injected directly into tumours, CPMV recruits innate immune cells such as neutrophils, macrophages, and natural killer cells, into the tumour microenvironment, while activating B and T cells to create long-lasting, systemic anti-tumour memory. This immune reawakening targets both the primary and metastatic tumours. To uncover why CPMV works so well, the team compared it to the closely related cowpea chlorotic mottle virus (CCMV), which does not produce anti-tumour effects. Both viruses are similarly sized and taken up by human immune cells at similar rates, but CPMV stimulates type I, II, and III interferons, proteins with known anti-cancer properties, while CCMV induces pro-inflammatory interleukins that fail to clear tumours. CPMV RNA also persists longer and activates toll-like receptor 7 (TLR7), a key trigger for anti-tumour immunity, whereas CCMV RNA does not.
CPMV offers a cost-effective advantage, as it can be grown in plants using sunlight, soil, and water. The team is now working toward advancing CPMV to clinical trials, aiming to translate these promising findings into safe and effective cancer immunotherapies.
Image Credit: Anthony Omole, (MedicalXpress)
By University of California – San Diego. Edited by Sadie Harley, reviewed by Andrew Zinin
Article can be accessed on: MedicalXpress
