You might wonder whether or not I've added rabies just to put a 'scare' in my readers, but the truth is that the DoD, the NIH, NIAID, and Thomas Jefferson University have teamed up to produce a genuine vaccine candidate built on the rabies vaccine.
In a way, it makes sense. In Africa, many animals contract both rabies and Ebola and can spread both diseases to human through a bite. And until recently, very few with deep pockets felt inclined to put their investment dollars into a vaccine that might be used or not (vaccines do have a shelf life). Let's face it, most pharmaceutical companies prefer to make a profit, and their investors expect one, so it makes selling the idea much easier if you can guarantee sales year after year. Rabies vaccines must be repeated every 1-2 years (at least in our dog they do), so it's probable that wildlife managers and zoos would line up to buy something that protected against rabies and filoviruses.
So, how is a rabies vaccine going to work against Ebola—a very different type of virus. Put simply, it has to be genetically modified, which makes this a recombinant vaccine. Dr. Joseph Blaney who works for the NIAID (National Institute of Allergy and Infectious Diseases) is listed as a lead author on some of the research that first appeared in publication around August, 2011 (I say 'around' because this is the earliest version I could find online, but I'm not precluding and earlier publication). Another researcher on the project is Dr. Peter Jahrling, one of the giants in filovirus research—and a name familiar to anyone who has read 'The Hot Zone'. These two along with many other diligent researchers have found what appears to be a 'bivalent' (confers immunity for two serotypes) vaccine with income potential, which means it might actually be produced.
To create their little chimera, the researchers took what is called an attenuated rabies virus. Attenuated means that it has been altered so that it is weak, less vigorous. The Ebola/Rabies vaccine uses a recombinant version of this attenuated virus. This virus is derived from the current rabies vaccine by reverse engineering the vaccine to produce a rabies virus genome.
The rabies virus is spliced with a gene that causes it to produce Ebola glycoproteins on its surface. Both rabies and filoviruses like Ebola and Marburg have an outer envelope that is derived from the previous victim's cells (or from cells in your own body). When the virus approaches a new cell, the glycoproteins do a sort of 'handshake' with exterior proteins on that cell's membrane, and since the virus is dressed appropriately, the victim cell says 'come on in' and commences a process called endocytosis (bringing the virus in through the door). Glycoproteins (GPs) are produced by the host cell along with all the other virus products: the virus cannot reproduce on its own, it must hijack your cells and force them to make copies of its RNA genome and all the proteins required to make new virus particles.
The Rabies/Ebola vaccine candidate expresses Ebola GPs on its outer surface, making it look just like an Ebola virus, training the host body's immune system to recognize the trickster. According to the research, both the IgG and complement systems within the body are activated. It is not known yet whether or not T-cell activation occurs. IgG is a type of immunoglobulin (an antibody), and the Complement System consists of 20 types of cells that circulate through the blood system on the lookout for invaders. Complement cells are amazing inventions (thank you, Lord), because they're in two parts.
When a complement cell sees an invader, it attaches to the invader or to an exposed portion of IgM or IgG (if antibodies are even involved), and it then splits in half. Half stays with the invader, and the other half runs out to gather re-enforcements.
According to published research on the Rabies/Ebola vaccine candidate, not only does the recombinant (rRAB) vaccine induce an immune response in mice and monkeys, it is likely to do the same in humans.
Much more here http://sharonkgilbert.com/?p=2560
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