{"id":221,"date":"2019-02-18T21:53:47","date_gmt":"2019-02-18T21:53:47","guid":{"rendered":"https:\/\/admin.acceleratingscience.com\/atomic-resolution\/2019\/02\/18\/researchers-use-cryo-em-in-the-search-for-a-universal-flu-vaccine\/"},"modified":"2019-02-18T21:53:47","modified_gmt":"2019-02-18T21:53:47","slug":"researchers-use-cryo-em-in-the-search-for-a-universal-flu-vaccine","status":"publish","type":"post","link":"https:\/\/www.thermofisher.com\/blog\/atomic-resolution\/researchers-use-cryo-em-in-the-search-for-a-universal-flu-vaccine\/","title":{"rendered":"Researchers Use Cryo-EM in the Search for a Universal Flu Vaccine"},"content":{"rendered":"

Influenza is oftentimes treated as nothing more than a yearly nuisance, a regrettable but unavoidable part of the winter season. In fact, less than half of Americans obtained the flu vaccine in 2018<\/a>, indicating the lax attitude many have toward the disease. The flu continues to kill anywhere between 290,000-650,000 people per year<\/a>. Over 100 years ago, the lethal Spanish flu devastated the world, killing anywhere from five to ten percent of the global population. Today, scientists continue to search for a \u201cuniversal flu vaccine\u201d to not only alleviate the substantial cost of yearly vaccine development but also stave off potentially another lethal flu pandemic.<\/p>\n

How does the flu vaccine work?<\/strong><\/h3>\n

The influenza virus uses a glycoprotein on its surface, called Hemagglutinin (HA), to bind to host cells; it consists of a binding \u201chead\u201d attached to the virus by an extended \u201cstalk\u201d region. The annual influenza vaccine<\/a> contains these HA proteins, purified from infected samples. When they are introduced into the human body it produces antibodies specific to the HAs, thereby building an immunity for the real virus. There are several difficulties with this method. First, these antibodies bind to the head region, which is highly variable; this is the reason the vaccine must be reformulated annually. Second, it requires researchers to anticipate what variants of the HA are most likely to become prominent in the coming flu season.<\/p>\n

The goal of most \u201cuniversal flu vaccines\u201d is, therefore, finding alternate means of halting the virus\u2019s progression.<\/p>\n

How electron microscopy can help<\/strong><\/h3>\n

The particular difficulty of studying membrane protein, like HA, is that they do not retain their native structure once they are removed from the membrane environment. Not only that, but as fusion protein, HAs are capable of significant structural change between their bound and unbound forms. HAs are also densely packed on the surface of the virus, meaning that binding involves the action of multiple HA species<\/a>. Cryo-electron microscopy (cryo-EM) techniques are uniquely suited to analyze these challenging systems. By flash freezing (vitrifying) the sample prior to analysis, the entire virus is \u201cfrozen in time,\u201d allowing detailed investigation of the complex, transient structures on its surface. What follows is just a small subset of the many ways in which cryo-EM is at the forefront of influenza research.<\/p>\n

\u00a0<\/em><\/p>\n

Cryo-electron microscopy clearly shows protein densely covering the surface of influenza viruses. <\/em>Kosik et al., Rockefeller University Press, 2019.<\/a><\/em><\/p>\n