Rabies Virus Helps Deliver Drugs into the Brain

Neuroscience and Neurology CategoryOne of the greatest challenges neurologists face is successful delivery of drugs to the brain. This is because a special filtering layer of tissue, called the blood brain barrier, protects the brain and spinal cord. The barrier acts like a molecular sieve, allowing only properly sized molecules through. This means that any medication needing to reach the brain (for example, to kill a brain tumor) needs to be small enough, and even then, it is difficult to target the drug to specifically reach the brain.

Kumar and his colleagues from Harvard Medical School have developed a potentially revolutionary drug delivery method, taking advantage of a known master infiltrator of the brain: the virus responsible for rabies, also known as the rhabdovirus. Rabies viruses travel from the site of infection (a local wound bite) to the nerves, through which it gains access to the brain. It is one of the few viruses known to be nearly 100% deadly to mankind, when vaccination has not been administrated. Kumar and colleagues took advantage of the virus’ neurotropic ability by isolating a protein from the viral outer layer used to bind to the brain cells. They then attached an experimental drug to the purified fragment of protein, a small-interfering RNA. This RNA-peptide complex showed highly specific ability to access neurons in the brain that expressed receptors to the neurotransmitter acetylcholine. This high specificity of drug action was demonstrated to only occur in the brain, and not in other tissues of the body.

In this study, the drug was injected into the tail of the mice, targeting the blood vessels. Using small interfering RNA (siRNA) as a drug treatment for many diseases has been powerfully successful in other animal models, but the problem has always been the process of making it a practical drug for clinical application. Therefore, this new technology developed by Kumar et al sheds light into a new, non-invasive and feasible way to deliver siRNA specifically to the brain.

siRNA is gaining popularity as a preferred drug treatment method since its early conception in the past seven years. It takes advantage of the cell’s ability to stop its own protein production as soon as a short RNA sequence corresponding to the protein is detected outside of the cell’s nucleus. This triggers a powerful protein synthesis arrest, which can be harnessed to modulate or treat diseases such as diabetes, Hepatitis C, and even transplant rejection.

In 2006 the discoverers of siRNA, Andrew Z. Fire and Craig C. Mello, won the Nobel Prize in Medicine.


Kumar, P. et al. Transvascular delivery of small interfering RNA to the central nervous system. Nature 448, 39-43 (2007).


    good job, well done

  • jitesh arora

    GREAT ARTICLE.cheers to your work.

  • kranthi

    great research.hope it works well for humans as well.

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  • Paul

    ever see I Am Legend? Now I’m scared.

  • hunkertothebunker

    ever see I Am Legend? Now I’m scared.

    Ditto! Let’s all take the virus with the biggest similarities to the various zombie viruses, mess around with it on a DNA level to make a more efficient way to infiltrate the brain. Do these people not watch TV at all!?

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  • Amy

    goes to show sci-fi can be just as much science as fiction. More info on the latest developments in brain and spinal cord research.

  • ruby

    hi,,im 23 years old…im working at government hospital…there’s few of cat living there,,,while im on duty there was a kitten who jump over my pants..i was shock..so what i do was i kick it..ofcourse/.,,the kiiten scratch on my skin..i dnt know if im bitten or scratch….i consulted the resident physician,,,he said it was category 3..so i went at animal bite for injections for ant tetanus,anti rabies and so be it,
    ,i had my ERIG vacination ..its so expensive! it was so painfuuul were in it ingected directly to the wound,, …equally compute accdgly to my wieght,,,
    it was DAy 8 wen i got it that vaccnation… ideally, ERIG is given upto day 7 after u biten by a rabid animal…..ryt?
    i was worried about my situation..do u think im already protected or not?..the last anti rabies vacination are not given yet to me due for some reason,..i think that was a 1st booster..
    do u think guys its okey to hold or missed or delay the booster vaccination??? im not satisfied from the animal bite what they told me..i need ur opinion pls send me at my email add…plss..cynder_18k@yahoo.com

  • Lorrie

    So…my question is this: if viruses are not life as we define it and know, and viruses are not motile/mobile — how are they moving through anything? Is it not more accurate to describe viruses as potentially functional pieces of coding regions of DNA?RNA? So, it is the proteins (those wild and crazy things that want to act as if they had a mind of their own) as a result of the activity? Isn’t this more accurate?

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Karen Vieira, MBA, PhD

Karen Vieira, MBA, PhD, has written about medical research, medical procedures, food ingredients, herbal remedies, pharmaceutical drugs, condo construction, real estate and computer consulting to mention a few.

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