Swiss scientists have created artificial viruses that can be used to target cancer. These designer viruses alert the immune system and cause it to send killer cells to help fight the tumor. The results, published in the journal Nature Communications, provide a basis for innovative cancer treatments.
Most cancer cells only provoke a limited reaction from the immune system - the body's defense mechanism - and can thus grow without appreciable resistance. By contrast, viral infections cause the body to release alarm signals, stimulating the immune system to use all available means to fight the invader.
The researchers built artificial viruses based on lymphocytic choriomeningitis virus (LCMV), which can infect both rodents and humans. Although they were not harmful for mice, they did release the alarm signals typical of viral infections. LCMV targets also lymphoid tissue stroma cells expressing the alarmin interleukin-33. By triggering interleukin-33 signals, artLCMV elicits CTLeff responses of higher magnitude and functionality than those induced by replication-deficient vectors.
The virologists also integrated certain proteins into the virus that are otherwise found only in cancer cells. Infection with the designer virus enabled the immune system to recognize these cancer proteins as dangerous.
Superior anti-tumor efficacy depends on interleukin-33 signalling, and a massive CTLeff influx triggers an inflammatory conversion of the tumor microenvironment.
The unique combination of alarm signals and the cancer cell protein stimulated the immune system to create a powerful army of cytotoxic T-lymphocytes, also known as killer cells, which identified the cancer cells through their protein and successfully destroyed them.
Designer viruses stimulate the immune system to fight cancer
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