Vaccination on the Horizon for Severe Viral Infection of the Brain

The human body is home to a multitude of viruses and bacteria. Some of them house themselves in the gut, others on the skin and other body organs. They are often needed in important bodily functions, but, under certain circumstances some can also cause diseases. One such example is the JC virus, a member of the polyoma tumor virus family, which causes a rare and fatal disease called progressive multifocal leukoencephalopathy (PML).

In a new research, scientists from the University of Zurich and the University Hospital Zurich have revealed that they have found what they believe could be possible new treatment methods for this rare brain disease. They have discovered the specific antibodies that play a key role in combating the viral infection. The good news is that a vaccine against the disease “progressive multifocal leukoencephalopathy” could now be developed.

It is estimated that more than 60 percent of the global population are infected with this virus and it typically lives in the kidneys and some other organs. This virus can cause the PML infection in the brain, which, in most circumstances, is fatal. The main cause behind this infection is a weak immune system.

An international team of researchers which includes researchers from the University of Zurich, the University Hospital Zurich, the National Institutes of Health in the USA, San Raffaele Hospital in Milan, the University of Tübingen, and the UZH spin-off Neurimmune conducted two studies and found that the antibodies in PML patients often fail to recognize the JC virus they are infected with. Roland Martin, professor of neurology at the University of Zurich explains that in normal healthy people, the immune system keeps it in check and does not let it spread its tentacles. However, in people suffering from conditions like tumors, leukemia, AIDS, autoimmune diseases, the immune system is compromised and the JC virus gets the opportunity to alter its genetic information and infect the brain.

It is seen that in multiple sclerosis (MS) patients, when they are treated with a particular antibody, TysabriTM, it prevents immune cells from reaching the brain “ and at the same time, it also inhibits the brain’s immunosurveillance. Sensing the opportunity, the JC virus enters the brain during the treatment undetected, and causes PML. This is in fact the most significant side effect of the otherwise highly effective TysabriTM. Since, there is no effective treatment for PML infection; many MS patients who develop PML infection meet a fatal end. The only means by which the JC virus can be removed from the brain is by restoring the immune system function completely.

Through their study, the researchers have now found potential ways to vaccinate against PML preventatively. In case, the brain is already infected, they have developed a means to treat it with virus-specific human antibodies. Martin explained that they managed to isolate antibody-producing cells from a patient who survived PML and used them to produce neutralizing antibodies against the JC virus. The advantage these human antibodies have is that they recognize the most important mutants of the JC virus that can cause PML.

They vaccinated mice and a PML patient with the virus’ coating protein, and were able to demonstrate that the antibody response was so strong that the patient was soon able to eliminate the JC virus. This breakthrough active vaccination method has been developed at the University of Zurich and the University Hospital Zurich, and has already been used successfully on two more patients. The JC-virus-specific antibodies for the treatment of the existing brain infection were developed by the group at the University of Zurich and the University Hospital Zurich together with colleagues from the University of Tübingen and the biotechnology company Neurimmune in Schlieren.

References

https://medicalxpress.com/news/2015-09-vaccination-horizon-severe-viral-infection.html

https://www.mediadesk.uzh.ch/articles/2015/auf-dem-weg-zu-einer-impfung-bei-schwerer-virusinfektion-des-gehirns_en.html