Researchers solve viral superinfection mystery

By Liz H. ‘10

Interaction between a T-cell (purple) and another cell of the immune system.

The ability of a common virus known as CMV to cause a “superinfection” and infect humans multiple times has puzzled scientists until recently.  Researchers at the Oregon Health and Science University Vaccine and Gene Therapy Institute have reported the mechanism that CMV uses to evade the immune system and re-infect humans, in a study published in the April 2nd issue of Science.  Their findings shed light on how this virus may be used in the development of CMV-based vaccines for other diseases.

Cytomegalovirus (CMV) does something that not many viruses can do:  it can re-infect people who previously have been infected by CMV and have already developed an immune response to the virus.  This is unusual for a virus, because the immune system usually “remembers” previous infections with viruses and other pathogens and can mount a strong immune response upon re-infection with a specific pathogen.

The researchers studied CMV-infected monkeys in order to understand how the virus overcomes detection by the immune system.  They discovered that CMV avoids a special type of white blood cell called CD8+ T cells, which are responsible for killing cells that are infected with a pathogen.  CD8+ T cells recognize infected cells by small molecules on the exterior surface of infected cells known as MHC I.  These molecules display small pieces of an invading pathogen and present them to the T cells.  This presentation of infectious material ultimately signals T cells to start destroying infected cells.

In order to evade these T cells, CMV makes proteins that interferes with the presentation of viral pieces by MHC I molecules and stops them from recruiting T cells to infected cells.  “In essence, CMV is able to cut off an infected cell’s call for elimination. This allows CMV to overcome this critical immune barrier during re-infection,” explains author Klaus Frueh.

The study has interesting implications in the design of CMV-based viral vaccine vectors.  Viral vaccine vectors contain a modified, harmless virus that carries a vaccine for another pathogen to the body.  Although the body develops immunity to the pathogen, it also develops immunity to the viral vector, which means that the viral vector can only be used for one type of vaccine.  Since CMV does not elicit an immune response upon re-infection, it makes an attractive vaccine vector candidate that could potentially carry vaccines against other pathogens, such as HIV, hepatitis C, tuberculosis, and malaria.

CMV is a member of the herpesvirus family and infects 50-80% of the US population by age 40.  Most people do not have any symptoms of CMV infection and do not become ill.  But for those with weakened immune systems, including infants and the immunocompromised, CMV can cause serious complications.  With this new understanding of how CMV evades the immune system, scientists may be able to start utilizing the virus for the benefit of human health.

Want more information?

CMV infection

Press Release

13 thoughts on “Researchers solve viral superinfection mystery”

  1. Liz,
    This is a really interesting find for your blog piece! I had no idea that it was possible for a virus to reinfect someone after the immune system had already made an immune response. Really great topic!

  6. This is a really interesting.
    Genveritas Technologies one of the quickly developing ISO Consultants Service Provider in India situated in Bangalore, Karnataka. We provide ISO Consulting | ISO Implementation | ISO Auditing | ISO Training services to the accompanying International Standards.

    With rich experience of ISO Consulting and ISO Implementation, we guarantee that the picked ISO standard execution doesn’t turn out to be only a documentation movement however it turns into a lifestyle for the association so an appropriate Management System is successfully introduced to your esteemed organization in Bangalore.

  7. In a new study, a team of Michigan State University scientists shed light on these enigmatic, yet captivating giant microbes and key aspects of the process by which they infect cells. With the help of cutting-edge imaging technologies, this study developed a reliable model for studying giant viruses and is the first to identify and characterize several key proteins responsible for orchestrating infection.

  9. Good. I really like this, I just found out about this. This was an incredibly wonderful article.
    Thanks for providing these details.

  12. Norton VPN is a service that protects the user from threats and hacking issues over the public network, especially when accessing public Wi-Fi. However, if Norton VPN is not working, it means that it has been blocked or the device settings have been modified.

    Norton VPN blocks all other types of traffic except for browsing and what is needed for other applications. But sometimes a user needs to access something else through the browser.

    This could be due to some types of games or video streaming sites that need an outside connection to work properly.

    Or there could be specific websites with limitations on what kind of content can be accessed in certain countries, which can also lead to browsing problems for Norton VPN users trying to access them.

    Norton VPN not working on your Mac? You are not alone. There are many people with the same problem. This is because of the latest updates to Norton Security, which has caused the Norton VPN no longer work on Mac.

    We will tell you some of the solutions to fix Norton VPN not working on Mac.

    Solution 1:

    First of all, go to the “System Preferences” and then select “Security and Privacy.” From there, find the “Firewall” section.

    Solution 2:

    Check if you have a third party firewall on your Mac computer that may be blocking your Norton VPN from connecting. To do so, go to “System Preferences” and select “Security & Privacy”. In the “Privacy” tab, click on “Firewall Options” and check if any third party firewall is blocking connections from your Norton VPN.

    Solution 3:

    If none of these solutions work for you then please contact our 24/7 customer support team.

    We hope that you are able to troubleshoot your issues of “Norton VPN has stopped working” program with the list of solutions that we have provided you.

Comments are closed.