Danish dogs will receive a cancer vaccine inspired by the virus

Fifteen Danish dogs with advanced cancer will receive a new type of therapeutic vaccine that will hopefully rid them of the disease and pave the way for testing on humans.

Unlike preventive vaccines, therapeutic vaccines are not used to prevent a person from contracting a disease, but rather to support an immune system that is already fighting an invader. This one should trick the immune system of dogs into believing that they are attacked by a virus and stimulating a reaction.

This work is part of international efforts to take advantage of the vigorous immune system response against viruses and to redirect it to other types of attacks – by bacteria, parasites and viruses. and some types of cancer.

The research is led by Prof. Ali Salanti, a translational microbiologist at the University of Copenhagen, Denmark, and is the result of work in various projects, including PLACMALVAC.

"We are going to test the vaccine in the pets that go to the veterinarians with this disseminated cancer and … with (the results), we will try to raise funds for production and (testing) at the Man, "he said.

His team and others from around the world were intrigued by the success of a new cervical cancer vaccine and teamed up with Dr. John Schiller of the US National Cancer Institute, who contributed to the development of the vaccine, to explore the reasons for its effectiveness.

shell

Cervical cancer is caused by a virus and the vaccine consists of a shell of the virus – called a capsid – emptied of its genetic material to make it harmless. The capsid is enough to trigger the immune system to build lifelong defenses against infection and therefore against cervical cancer.

Most cancers are not caused by viruses, but both carry on their surface markers, called antigens, that cause the immune system to make antibodies to fight them. However, the problem is that tumors also deploy a range of tactics to escape the immune system and that the body's response is often too weak to attack them effectively.

Professor Salanti's group has patented a way to make capsid-shaped particles from proteins, which can be used to transport molecules such as antigens into the body. To test whether this approach could help fight cancer, Professor Salanti and his team reconstructed the markers found on bad cancer tumors in mice and joined them to capsid-type particles. They then injected this compound into mice genetically engineered to have bad cancer. The immune system of the mouse reacted as if it was under viral attack, the tumors narrowed and in some cases disappeared.

He hopes that this method of stimulating the immune system could have consequences other than the treatment of cancer.

"The idea is that if we could give a protein an appearance (a capsid-like particle), we could protect for life against any disease (where antibodies are important)," said Professor Salanti.

The next step is to test it in the dog because its cancers carry to the surface the same identification proteins as humans, in order to move on to human trials.

Malaria

But for Professor Salanti, proving that the vaccine works in humans is a step toward another seemingly unrelated goal: developing a vaccine against malaria badociated with pregnancy.

Postgraduate researcher Professor Salanti has discovered why women, who often developed resistance to malaria when they were younger, become vulnerable during pregnancy – often losing their babies. Malaria during pregnancy is responsible for 15% of maternal deaths and, if it does not kill the fetus, it can reduce its birth weight.

During his doctorate, Professor Salanti discovered that the answer lay in the placenta – the temporary organ that forms between a mother and her growing fetus. Small hooks or receivers are scattered along the side of the mother. And, on the surface of red blood cells infected by malaria, are proteins perfectly designed to adhere well to these hooks, thus disrupting placental activities.

Professor Salanti felt that if he could vaccinate a woman with the protein found on the surface of malaria-infected cells, her immune system might have to produce antibodies that would be ready to attack the parasite – and thus protect her placenta – became pregnant.

Some 15 years later, Professor Salanti developed such a vaccine. It has been proven safe during the first human trials in Germany and has just pbaded a second round of safety trials – not yet published – in Benin, showing that it is safe for women of childbearing age. However, Professor Salanti believes that the vaccine in its current form is not optimal.

Over the past decade, more and more evidence has shown that many vaccines against bacterial and parasitic infections confer only short-term protection, which means that repeated vaccinations are needed. According to him, this is not a practical solution for African countries run out of money.

Instead, Professor Salanti has been looking for a different vaccine delivery method and he hopes that the capsid-based virus type particle technology used in the dog tests could provide the answer.

"We will start with a cancer vaccine and then … develop the malaria vaccine," he said.

Professor Robert Sauerwein, a member of the WHO Malaria Vaccine Advisory Committee at the Radboud University of Nijmegen in the Netherlands, said the use of such an approach to Malaria is a possibility that deserves to be explored. "Virus-like particles can induce better responses, but it depends a lot on the product," he said. "It's worth trying on a case-by-case basis, but there is no guarantee."

In the meantime, Danish dogs may be far from Benin, but Professor Salanti is also trying to steer his cancer research towards inexpensive solutions.

"People forget that in Africa, most types of cancer are condemned to death, so we hope to be able to offer something more profitable that will also be available in these parts of the world."