Archive for December 20th, 2013

HIV: Slipping under the radar

20 December, 2013

See on Scoop.itVirology News

HIV avoids triggering the cell receptors that initiate the host’s innate immune responses. It seems that the virus achieves this evasion by using its protein coat to hide its nucleic acids until they are beyond detection.

Ed Rybicki‘s insight:

You know, HIV’s genome is only 10 kb in size – yet the number of mechanisms the virus has eveolved to go stealthily among the immune responses of the host are quite remarkable.  There is the fact that Env proteins are heavily glycosylated, which hides them from antibodies – and that they are shed very easily, meaning the HIV virion has very few of them.

There is the fact that the virus goes quiescent after infection and genome integration, by downregulating its own expression AND that of CD4 receptors.

And now this: dodging detectors INSIDE the cell in order to safely deliver the DNA version of its genome directly into the nucleus.  Truly, life for viruses is an emergent property making them so much more than the sum of their parts.

See on www.nature.com

Narcolepsy an autoimmune disease – and how it is associated with swine flu

20 December, 2013

See on Scoop.itAquatic Viruses

As the H1N1 swine flu pandemic swept the world in 2009, China saw a spike in cases of narcolepsy — a mysterious disorder that involves sudden, uncontrollable sleepiness. Meanwhile, in Europe, around 1 in 15,000 children who were given Pandemrix — a now-defunct flu vaccine that contained fragments of the pandemic virus — also developed narcolepsy, a chronic disease.

Immunologist Elizabeth Mellins and narcolepsy researcher Emmanuel Mignot at Stanford University School of Medicine in California and their collaborators have now partly solved the mystery behind these events, while also confirming a longstanding hypothesis that narcolepsy is an autoimmune disease, in which the immune system attacks healthy cells..

Ed Rybicki‘s insight:

It has been an interesting set of observations that have led up to this: I have chronicled some of them here in Virology News, as I picked up on how both the H1N1 2009pdm vaccine and the native virus seemed to be associated with narcolepsy.

And now the mystery is partly solved: some genetically-predisposed individuals produce CD4+ T-cells that recognise enogenous hypocretin, that are triggered by swine flu – and perhaps also by other flu virus.

That is, of course, not the whole story – but at least we are part fo the way to understanding how this puzzling and rather disturbing correlation of particular influenza viruses and narcolepsy occurs.

See on www.nature.com