Researchers make inroads toward a cure for the flu
Viruses aren't easy to defeat, but scientists are taking creative approaches from multiple angles.
The hallmark of viruses — one of the first things you learn about them in a college biology class — is that they are both structurally simple and incredibly wily. The reason they are so hard to fight is that viruses are able to change and adapt to new circumstances more easily than complex germs like bacteria or parasites. In fact, they are such an ancient and simple thing that some scientists don't even know whether to categorize viruses as being alive or not (see video below for that explanation).
It's for these reasons that illnesses caused by viruses — the flu, the common cold, herpes, and HIV/AIDS — are all so difficult to treat. And it's because of viruses' ability to mutate that they are so dangerous and why the flu vaccine given one year might not protect you from the flu the next year.
But researchers are getting closer to developing treatments, at least for the flu virus, to create a permanent vaccine. With flu season approaching in the United States, you can get a flu shot (here's how to make that vaccination as effective as possible) and there are a few promising avenues of inquiry for a future flu "cure."
Worldwide, tens of millions of people get the flu each year, and, some years, up to 5 million get a severe version of it; the flu kills about 500,000 people a year, according to a 20-year retrospective study published in the journal Lancet. Those most likely to suffer serious effects from the flu are children under 2 years old, the elderly and people with compromised immune systems. But those numbers are on average — the impact can be greater in an epidemic year, and a pandemic is even worse (though the word can also be used to indicate the ease with which a flu spreads, and its potential, rather than the number of people it gets sick). That's why a flu vaccine that protects for more than one flu season could have even greater life-saving potential than the numbers indicate.
Dr. Taia Wang, Instructor of Clinical Investigation for the Molecular Genetics and Immunology Lab at Rockefeller University in New York City, says that a flu vaccine that protects for multiple seasons is a real possibility. "Major strides have been made in the last few years in flu vaccine development," Dr. Wang told From The Grapevine. The fact that there are several vaccines currently in pre-clinical and clinical trials means that "it is likely that at least one will prove protective against a broad array of flu viruses," she said.
So how exactly do some of these new vaccines potentially work? Well, first you have to know a little about how the flu virus (see illustration above) functions.
First, what we know: "We usually become infected with the flu by inhaling small droplets that contain virus; the virus then infects cells in the respiratory tract, which triggers the body to mount an immune response to clear the virus. The symptoms felt during a flu infection (fever, fatigue, headache, etc.) are generally a result of this immune response," explained Dr. Wang.
Drilling down to the level of the virus itself, we see: An envelope made up of two types of glycoproteins, Hemagglutinin (HA) and neuramindinase (NA), surrounding a central core of viral RNA and some more proteins that protect the RNA (you'll remember from biology class that RNA is a type of genetic material). No mitochondria, no nucleus or other typical cell material, because a virus is not a cell — it's a virus. The HA and NA are what attach to (and release) virus progeny into a host cell — like, say, one in your lungs. It's these proteins that are the targets for antiviral drugs. The whole simple genius of the virus is that it uses its host cell to survive, replicate, mutate and spread (it can't do those things on its own).
So if you can stop the virus from being able to attach or transmit its material to a host cell, you stop the virus from spreading.
Yotam Bar-On, a Ph.D. candidate in immunology and cancer research at the Hebrew University of Jerusalem, has been focused on just that. He developed antibodies that bind to the NA, taking them out of commission in such a way that the body's own Natural Killer cells (NK) are able to do their job more effectively (we know that they can kill influenza viruses, but the viruses block them).
"Altogether, the novel antibodies we have developed will allow our immune system to respond more efficiently to a wide variety of influenza infections,” Bar-On told Health Canal.
So these larger spectrum antibodies from a vaccine response will aid our bodies in fighting the flu — including not just one strain, but a variety of them — from the cellular level.
"That these 'broadly protective' antibodies exist in some people suggests that it might be possible to elicit them by using the right vaccine," said Dr. Wang.
The influenza hemagglutinin protein reconfigures itself as it targets host cells to infect them. Until new analysis by Rice University and Baylor College of Medicine researchers, nobody had been able to study the intermediate states of the protein-refolding process that may be vulnerable to treatment with drugs. (Photo: Jeffrey Noel/Rice University)
Another study, by teams from Rice and Baylor Universities, has looked at the HA protein. “The purpose of hemagglutinin (HA) is to poke a hole between the two membranes,” Jianpeng Ma, a biochemist with joint appointment at Rice and Baylor, said via a statement from Rice. “They have to fuse so the genetic material will be injected into the human cell.”
By interrupting the fusion process between virus and human cell (illustrated above) by attacking the 'cap' that protects the virus (this is the very part of the virus the mutates so often and makes it such a strong defense against vaccines), the interior part of the HA is revealed; material which, researchers think, is much less able to mutate, and is therefore more susceptible to vaccines.
Obviously, viruses are tricky, even if they are simple. What's most hopeful about the current state of research is that scientists are looking at the problem from multiple angles — narrowing down the mechanisms toward a solution that will keep us healthier and ultimately save lives.
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