Designer Virus Uses Body’s Immune System to Destroy Cancer Cells

Cancer cells often grow without much resistance.

Because they are exceptionally good at dodging the immune system, they provoke only a half-hearted response from the body, allowing them to spread at will.

Viral infections, on the other hand, prompt the body to release alarm signals that activate the immune system and provoke the body to fight the foreign bodies.

Swiss researchers hope to capitalize on the body’s response to viruses in an effort to combat the spread of various cancers.

The treatment employs an artificial virus that is harmless to the human body. Although the virus is benign, it releases an alarm signal in the body that is typical of viral infections.

Because the virus is injected with a protein that is only found in cancer cells, the body’s immune system is able to detect the virus, identify the cancer protein, and then hunt down similar cancer cells that have the same protein.

Researchers theorize that the technique could be developed so that proteins removed from a patient’s own tumor could be injected into the designer virus cells. Once the protein-filled virus is injected into the patient, it would trigger a powerful response against that patient’s own cancer.

In tests on mice, the designer virus initiated remission without harming the mice.

A twist on an old idea

The idea of using viruses to treat cancer dates to the early 20th century when doctors noticed that cancer patients had significant remission following viral infections.

Oncolytic, or cancer-killing, viruses date to the 1980s, but researchers haven’t fully isolated how viral therapies actually kill cancer cells. They do suspect, however, that the viruses attack in a variety of ways: by directly infecting the cancer cells, by triggering an immune response, and by interrupting the tumor’s blood supply.

In order to understand the process, researchers injected mice with a modified virus, and they discovered that the virus didn’t infect healthy organs, and it didn’t make the animals sick. The virus did infect blood vessels inside of tumors.

Furthermore, they found that while the virus did infect a small percentage of the tumor cells, the bulk of the tumor was destroyed by the body’s own immune system.

The theory is that after some of the tumor cells were directly affected by the virus, the resulting infection exposed the tumor proteins so that the body recognized them as invaders.

The virus seems to jolt the immune system into action, which is a welcome development for physicians who have invested significant resources trying to understand why the immune system doesn’t naturally detect and attack cancer cells.

Researchers theorize that multiple strains of the virus injected with different types of proteins could be used to treat patients whose cancer has mutated or metastasized.

Although immunotherapy, which harnesses the body’s own immune system to fight cancer, has shown a fair amount of success, only about half of the patients who try it see results.

Human trials represent the next stage of the process for the Swiss researchers.