New advance in viral cancer immunotherapy

Vaccinia viruses are therapeutic tools with different biomedical applications depending on the characteristics of their strains. For example, the strain called MVA (modified vaccinia virus Ankara) is incapable of replicating in mammalian cells, but instead triggers a powerful immune system response and is used to develop vaccines against COVID-19 or AIDS. On the other hand, other strains such as the Western Reserve (WR) or the Copenhagen strain (Cop), which reproduce efficiently in tumor cells, are used to develop cancer treatments. For this reason, they are called immuno-oncolytic viruses, and they are the basis of viral immunotherapy.

However, these viral strains have reduced immunogenicity, which means that they are less effective in activating patients’ immune responses against tumors.

Now, a work led by the University of Barcelona (UB), the Bellvitge Biomedical Research Institute (IDIBELL) in Hospitalet de Llobregat and the University of Munich (Germany) has developed a new strain of the vaccinia virus, which is capable of replicating in tumor cells and that at the same time maintains increased immunogenicity. Specifically, it has the ability to induce what is known as immunogenic cell death in tumor cells.

The work has been carried out with the support of the Spanish Association against Cancer (AECC) and the collaboration of the State Research Agency (AEI).

The new therapeutic tool, which has been tested in a wide variety of mouse models, has shown to have reduced toxicity and a great capacity and efficiency to activate immune responses against tumors. Likewise, the virus is effective in different oncological treatments, such as against melanoma, colon or kidney cancer.

“In addition, we achieved the total disappearance of the tumors in a very significant way when we administered the virus repeatedly,” details expert Juan J. Rojas, first author of the study and principal investigator of the Immunity, Inflammation and Cancer group at the Faculty of Medicine and Health Sciences of the UB and IDIBELL.

The team led by the expert Juan J. Rojas, first author of the study and principal investigator of the Immunity, Inflammation and Cancer group of the Faculty of Medicine and Health Sciences of the UB and IDIBELL. From left to right: Miquel Conesa, Maria Barcia, Juan José Rojas, Ana del Cañizo and Carmen Bueno. (Photo: UB / IDIBELL)

The discovery of this new viral strain represents a significant advance in viral immunotherapy research, and demonstrates its therapeutic potential to treat cancer patients.

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The study is titled “A new MVA ancestor-derived oncolytic vaccinia virus induces immunogenic tumor cell death and robust antitumor immune responses.” And it has been published in the academic journal Molecular Therapy. (Source: University of Barcelona)