Hidde Ploegh, Professor of Biology, MIT; Member Whitehead Institute
Description: In his role as a biochemist, Hidde Ploegh explains the "essential features of the lifestyle of the flu virus" discussing not only how viruses work to invade our systems and cause the flu, but also adding insights into the political and societal framework in which public health groups and governments deal viral disease.
The basic mechanics of how a virus-an organism that requires a host cell in which to reproduce-replicates itself is relatively simple. The virus attaches its eight short fragments of RNA (ribonucleic acid), fusing its shell with its host's shell using a protein called hemagglutinen. This allows the virus to enter the host cell where it creates a massive number of progeny viruses. Having done that, it releases its progeny from the host cell using an enzyme called neuraminidase. The 'H' of hemagglutinen and the 'N' of neuraminidase are the familiar acronyms in the virus name-H1N1 or Swine flu-we are familiar with. Each unique virus strain "speaks its own language" and is designated by other numerical suffixes.
The situation becomes complicated when the virus is not a uniquely human one, but one created when human and animal viruses mix. Our history of proximity to domesticated animals has allowed animal and human viruses to intermingle, resulting in the reshuffling of an even larger pool of genetic information and creating new strains of viruses. It causes further complications in the creation of vaccines to counter them.
Vaccines-using either an attenuated live strain or a subunit type, the only kind the FDA allows-are our defense against these viruses, allowing the body to develop its own antibodies against a specific viral invasion. While there have been instances of cultural or religious backlash against the use of vaccines that have prevented certain human-specific viruses from being completely eradicated, Ploegh emphasizes the importance of maintaining a clear understanding how these pathogens function.
And even as your body is mounting a defense against the flu by developing appropriate antibodies, the evolutionarily clever virus is working hard to evade those same antibodies. It mutates just enough to render last year's antibody response useless, explaining why a new flu shot is required each year.
With the basics of virus reproduction and vaccines explained, Ploegh takes questions from his audience. He further clarifies such topics as the use of chicken eggs to create the viruses and adds his own insights, as a member of the scientific board at Novartis, into how and why companies deal with the economic aspects of creating any new drug, in particular antivirals. Several of the topics raise questions about the public health aspects of monitoring and providing vaccines for the general population and whether Swine flu is truly a pandemic or media hype.
About the Speaker(s): An acclaimed researcher whose work focuses on the immune system, Hidde Ploegh joined The Whitehead Institute in 2005. Prior to that, he was a Professor of Pathology at the Harvard Medical School where he headed the school's immunology program since 1997. Ploegh has also been a Professor of Biology at MIT, working primarily in the Center for Cancer Research.
Ploegh has been interested in the molecular mechanisms by which the immune system responds to antigens-substances such as toxins, bacteria, or foreign cells from transplants which, when entering the body, trigger the production of antibodies. His recent focus has been on how certain viral proteins interfere with this process.
Ploegh's research has contributed to the understanding of the immune system. He discovered a new mechanism by which viruses evade the immune system. Ploegh and his coworkers have been particularly interested in generating the chemical tools with which to probe a particular family of enzymes called proteases that are a key component of one of the major mechanisms by which proteins are degraded in cells.
Ploegh's 300-plus research papers include the June 24, 2004 cover story for the journal Nature, which described one of the mechanisms by which the immune system eliminates misfolded proteins. Ploegh has been working on members of the herpes virus family and plans to begin studying influenza at The Whitehead Institute.
Ploegh's honors include Correspondent of the Royal Dutch Academy of Sciences, National Institutes of Health Merit Award, Avery-Landsteiner Prize, and member of the American Academy of Arts and Sciences.
Host(s): Office of the Provost, MIT Museum
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