Comments on: Influenza virus attachment to cells http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/ About viruses and viral disease Sat, 11 Feb 2012 17:38:00 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Dnhamil http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-30849 Dnhamil Thu, 26 Jan 2012 05:33:00 +0000 http://www.virology.ws/?p=1308#comment-30849 Are the receptors on the host cell always present and it just so happens that viral proteins can bind to them in a complimentary fashion? Viruses are parasitic so why do host cells have receptors for them to attach to? Are the receptors on the host cell always present and it just so happens that viral proteins can bind to them in a complimentary fashion? Viruses are parasitic so why do host cells have receptors for them to attach to?

]]> By: Eka N Nawangsih http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-30417 Eka N Nawangsih Tue, 27 Dec 2011 04:11:00 +0000 http://www.virology.ws/?p=1308#comment-30417 Prof, i like your illustration about attachment of the virion to cells. it help me to understand how influenza viruses bound to proteins Prof, i like your illustration about attachment of the virion to cells. it help me to understand how influenza viruses bound to proteins

]]> By: khairunnisa http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-29738 khairunnisa Fri, 04 Nov 2011 05:04:00 +0000 http://www.virology.ws/?p=1308#comment-29738 Hello Prof. actually I love your blog very much. It helps me in understands better about the fascinating world of virology. I'm still an undergraduate student from Malaysia. Thanks prof. keep it up! ^^, Hello Prof. actually I love your blog very much. It helps me in understands better about the fascinating world of virology. I’m still an undergraduate student from Malaysia. Thanks prof. keep it up! ^^,

]]> By: profvrr http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-29194 profvrr Fri, 30 Sep 2011 11:19:00 +0000 http://www.virology.ws/?p=1308#comment-29194 The sialic acids bound by influenza viruses are attached to proteins. The identity of the protein does not seem to matter for influenza virus entry. Hence sialic acid is the receptor. The sialic acids bound by influenza viruses are attached to proteins. The identity of the protein does not seem to matter for influenza virus entry. Hence sialic acid is the receptor.

]]> By: Milind http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-29192 Milind Fri, 30 Sep 2011 11:11:00 +0000 http://www.virology.ws/?p=1308#comment-29192 there are reports that sialic acid is just a docking site not the receptor .why is it that we could not find  influenza virus receptor till date? there are reports that sialic acid is just a docking site not the receptor .why is it that we could not find  influenza virus receptor till date?

]]> By: Ghildiyal_sneha http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-28778 Ghildiyal_sneha Sat, 24 Sep 2011 02:01:00 +0000 http://www.virology.ws/?p=1308#comment-28778 is sialic acid inhibitor of influenza virus   is sialic acid inhibitor of influenza virus
 

]]> By: profvrr http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-22938 profvrr Thu, 12 Aug 2010 22:23:29 +0000 http://www.virology.ws/?p=1308#comment-22938 Possibly, although the presence of NA protein should remove sialic<br>acids from host proteins. Possibly, although the presence of NA protein should remove sialic
acids from host proteins.

]]> By: David http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-22921 David Sun, 08 Aug 2010 15:01:43 +0000 http://www.virology.ws/?p=1308#comment-22921 Is it possible the newly formed HA bind to host proteins having sialic acid in Trans-Golgi network? Is it possible the newly formed HA bind to host proteins having sialic acid in Trans-Golgi network?

]]> By: profvrr http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-22900 profvrr Wed, 04 Aug 2010 22:06:10 +0000 http://www.virology.ws/?p=1308#comment-22900 Thanks for picking that up - you are correct, the colors of the<br>spheres should be swapped. I have fixed the image. Thanks for picking that up – you are correct, the colors of the
spheres should be swapped. I have fixed the image.

]]> By: Ha-tag http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-22899 Ha-tag Wed, 04 Aug 2010 21:43:29 +0000 http://www.virology.ws/?p=1308#comment-22899 The spheres in the picture should have opposite colors, the last sphere, the sialic acid should be orange, corresponding the color of the chair in the structures on the right.<br><br>is that right? The spheres in the picture should have opposite colors, the last sphere, the sialic acid should be orange, corresponding the color of the chair in the structures on the right.

is that right?

]]> By: Headless HA: Universal influenza vaccine? http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-22090 Headless HA: Universal influenza vaccine? Thu, 27 May 2010 20:13:02 +0000 http://www.virology.ws/?p=1308#comment-22090 [...] virus infection are directed against the globular head of the HA, the protein essential for attachment to and entry into cells. Unfortunately, the HA head undergoes significant antigenic variation. The HA stalk is more [...] [...] virus infection are directed against the globular head of the HA, the protein essential for attachment to and entry into cells. Unfortunately, the HA head undergoes significant antigenic variation. The HA stalk is more [...]

]]> By: profvrr http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-21540 profvrr Tue, 15 Dec 2009 02:57:34 +0000 http://www.virology.ws/?p=1308#comment-21540 The NA protein is inserted into the plasma membrane before the virion<br>buds from the surface. Its presence may lead to removal of sialic<br>acids, which would prevent re-binding of the newly synthesized<br>particle. In theory at least; there are no data that directly answer<br>your question. The results in the paper you cite are consistent with<br>the idea that NA has some inhibitory effect during infection as would<br>be expected. Clearly there are significant differences between<br>infection and budding that are not fully understood. The NA protein is inserted into the plasma membrane before the virion
buds from the surface. Its presence may lead to removal of sialic
acids, which would prevent re-binding of the newly synthesized
particle. In theory at least; there are no data that directly answer
your question. The results in the paper you cite are consistent with
the idea that NA has some inhibitory effect during infection as would
be expected. Clearly there are significant differences between
infection and budding that are not fully understood.

]]> By: JJackson http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-21539 JJackson Tue, 15 Dec 2009 02:46:25 +0000 http://www.virology.ws/?p=1308#comment-21539 Thanks but that then begs the question why when a new virion is budded does it not immediately bind and restart the fusion process before the NAs cut it free. On both occasions you have a virion adjacent to cell what is the difference why is there a net benefit to having NA cleaving sialic resisdues? There obviously is one or neuraminidase inhibitors would not work. I saw this <a href="http://www.ncbi.nlm.nih.gov/pubmed/19879239" rel="nofollow">http://www.ncbi.nlm.nih.gov/pubmed/19879239</a> and assumed it was due to nuraminidase having an inhibitory effect on cell infection although that effect was significantly outweighed by the benefits when budding Thanks but that then begs the question why when a new virion is budded does it not immediately bind and restart the fusion process before the NAs cut it free. On both occasions you have a virion adjacent to cell what is the difference why is there a net benefit to having NA cleaving sialic resisdues? There obviously is one or neuraminidase inhibitors would not work. I saw this http://www.ncbi.nlm.nih.gov/pubmed/19879239 and assumed it was due to nuraminidase having an inhibitory effect on cell infection although that effect was significantly outweighed by the benefits when budding

]]> By: profvrr http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-21538 profvrr Tue, 15 Dec 2009 02:12:51 +0000 http://www.virology.ws/?p=1308#comment-21538 Always an interesting question. The idea is that during entry, the HA<br>binds and the particle enters before the slower-acting NA can remove<br>the sialic acid. This idea has some support from the HA assay;<br>initially virions bind red blood cells but after approximately 30<br>minutes the NA cleaves off sialic acid and reverses the HA. See<br><a href="http://www.virology.ws/2009/05/27/influenza-hemagglutination-inhibition-assay/" rel="nofollow">http://www.virology.ws/2009/05/27/influenza-hem...</a>. Always an interesting question. The idea is that during entry, the HA
binds and the particle enters before the slower-acting NA can remove
the sialic acid. This idea has some support from the HA assay;
initially virions bind red blood cells but after approximately 30
minutes the NA cleaves off sialic acid and reverses the HA. See
http://www.virology.ws/2009/05/27/influenza-hem….

]]> By: profvrr http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-19302 profvrr Mon, 14 Dec 2009 18:57:34 +0000 http://www.virology.ws/?p=1308#comment-19302 The NA protein is inserted into the plasma membrane before the virion<br>buds from the surface. Its presence may lead to removal of sialic<br>acids, which would prevent re-binding of the newly synthesized<br>particle. In theory at least; there are no data that directly answer<br>your question. The results in the paper you cite are consistent with<br>the idea that NA has some inhibitory effect during infection as would<br>be expected. Clearly there are significant differences between<br>infection and budding that are not fully understood. The NA protein is inserted into the plasma membrane before the virion
buds from the surface. Its presence may lead to removal of sialic
acids, which would prevent re-binding of the newly synthesized
particle. In theory at least; there are no data that directly answer
your question. The results in the paper you cite are consistent with
the idea that NA has some inhibitory effect during infection as would
be expected. Clearly there are significant differences between
infection and budding that are not fully understood.

]]> By: JJackson http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-19296 JJackson Mon, 14 Dec 2009 18:46:25 +0000 http://www.virology.ws/?p=1308#comment-19296 Thanks but that then begs the question why when a new virion is budded does it not immediately bind and restart the fusion process before the NAs cut it free. On both occasions you have a virion adjacent to cell what is the difference why is there a net benefit to having NA cleaving sialic resisdues? There obviously is one or neuraminidase inhibitors would not work. I saw this <a href="http://www.ncbi.nlm.nih.gov/pubmed/19879239" rel="nofollow">http://www.ncbi.nlm.nih.gov/pubmed/19879239</a> and assumed it was due to nuraminidase having an inhibitory effect on cell infection although that effect was significantly outweighed by the benefits when budding Thanks but that then begs the question why when a new virion is budded does it not immediately bind and restart the fusion process before the NAs cut it free. On both occasions you have a virion adjacent to cell what is the difference why is there a net benefit to having NA cleaving sialic resisdues? There obviously is one or neuraminidase inhibitors would not work. I saw this http://www.ncbi.nlm.nih.gov/pubmed/19879239 and assumed it was due to nuraminidase having an inhibitory effect on cell infection although that effect was significantly outweighed by the benefits when budding

]]> By: profvrr http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-19293 profvrr Mon, 14 Dec 2009 18:12:51 +0000 http://www.virology.ws/?p=1308#comment-19293 Always an interesting question. The idea is that during entry, the HA<br>binds and the particle enters before the slower-acting NA can remove<br>the sialic acid. This idea has some support from the HA assay;<br>initially virions bind red blood cells but after approximately 30<br>minutes the NA cleaves off sialic acid and reverses the HA. See<br><a href="http://www.virology.ws/2009/05/27/influenza-hemagglutination-inhibition-assay/" rel="nofollow">http://www.virology.ws/2009/05/27/influenza-hem...</a>. Always an interesting question. The idea is that during entry, the HA
binds and the particle enters before the slower-acting NA can remove
the sialic acid. This idea has some support from the HA assay;
initially virions bind red blood cells but after approximately 30
minutes the NA cleaves off sialic acid and reverses the HA. See
http://www.virology.ws/2009/05/27/influenza-hem….

]]> By: JJackson http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-19274 JJackson Sun, 13 Dec 2009 16:20:21 +0000 http://www.virology.ws/?p=1308#comment-19274 If I understand correctly the Neuraminidase prunes sialic acid residues from glycoproteins. This is useful in allowing a clean get away after budding and also to stop binding of virions to each other. How does the virus prevent its NAs from removing the residues it needs to bind onto the glycocaylx before fusion? Wouldn’t its NAs be freeing it as fast as it could bind? If I understand correctly the Neuraminidase prunes sialic acid residues from glycoproteins. This is useful in allowing a clean get away after budding and also to stop binding of virions to each other. How does the virus prevent its NAs from removing the residues it needs to bind onto the glycocaylx before fusion? Wouldn’t its NAs be freeing it as fast as it could bind?

]]> By: Influenza HA cleavage is required for infectivity http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-1565 Influenza HA cleavage is required for infectivity Tue, 23 Jun 2009 01:35:22 +0000 http://www.virology.ws/?p=1308#comment-1565 [...] influenza virus hemagglutinin (HA) is the viral protein that attaches to cell receptors. The HA also plays an important role in the release of the viral RNA into the cell, by causing [...] [...] influenza virus hemagglutinin (HA) is the viral protein that attaches to cell receptors. The HA also plays an important role in the release of the viral RNA into the cell, by causing [...]

]]> By: Souptopia http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-1340 Souptopia Mon, 01 Jun 2009 20:02:39 +0000 http://www.virology.ws/?p=1308#comment-1340 <strong>Influenza virus attachment to cells...</strong> Influenza virus attachment to cells... Influenza virus attachment to cells…

Influenza virus attachment to cells…

]]> By: Release of influenza viral RNAs into cells http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-955 Release of influenza viral RNAs into cells Wed, 06 May 2009 22:18:37 +0000 http://www.virology.ws/?p=1308#comment-955 [...] “Influenza virus attachment to cells” we left the intact virion on the cell surface. The next step is that the viral genetic information [...] [...] “Influenza virus attachment to cells” we left the intact virion on the cell surface. The next step is that the viral genetic information [...]

]]> By: duck http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-929 duck Wed, 06 May 2009 00:19:33 +0000 http://www.virology.ws/?p=1308#comment-929 Thanks very much for the reply, and for the whole blog - this is fascinating! Thanks very much for the reply, and for the whole blog – this is fascinating!

]]> By: profvrr http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-895 profvrr Tue, 05 May 2009 00:56:16 +0000 http://www.virology.ws/?p=1308#comment-895 Yes, some were developed years ago, but did not inhibit all HAs and<br>were never brought to market. However, sialic acid analogs have been<br>developed which inhibit the viral NA - these are the well known<br>antivirals oseltamivir and zanamivir. Sialic acid is the ligand for<br>the viral NA enzyme. I have an upcoming post on this topic. Yes, some were developed years ago, but did not inhibit all HAs and
were never brought to market. However, sialic acid analogs have been
developed which inhibit the viral NA – these are the well known
antivirals oseltamivir and zanamivir. Sialic acid is the ligand for
the viral NA enzyme. I have an upcoming post on this topic.

]]> By: Corey Philipp http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-894 Corey Philipp Tue, 05 May 2009 00:45:42 +0000 http://www.virology.ws/?p=1308#comment-894 Has there been any success to developing compounds that can out compete the HA ligand? Something that would bind stronger to sialic acid. I could see this as an attractive target for intervention. Has there been any success to developing compounds that can out compete the HA ligand? Something that would bind stronger to sialic acid. I could see this as an attractive target for intervention.

]]> By: profvrr http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-885 profvrr Mon, 04 May 2009 20:31:22 +0000 http://www.virology.ws/?p=1308#comment-885 Sialic acids are in every cell and have many functions. A few<br>examples: Sialic acid-rich oligosaccharides on the glycoconjugates<br>found on surface membranes help keep water at the surface of cells.<br>Since water is a polar molecule with partial positive charges on both<br>hydrogen atoms, it is attracted to cell surfaces and membranes. This<br>also contributes to cellular fluid uptake. Sialic acid in the form of<br>polysialic acid is an unusual posttranslational modification that<br>occurs on the neural cell adhesion molecules, NCAM. In the synapse,<br>the strong negative charge of the polysialic acid prevents NCAM<br>cross-linking of cells. Sialic acids are in every cell and have many functions. A few
examples: Sialic acid-rich oligosaccharides on the glycoconjugates
found on surface membranes help keep water at the surface of cells.
Since water is a polar molecule with partial positive charges on both
hydrogen atoms, it is attracted to cell surfaces and membranes. This
also contributes to cellular fluid uptake. Sialic acid in the form of
polysialic acid is an unusual posttranslational modification that
occurs on the neural cell adhesion molecules, NCAM. In the synapse,
the strong negative charge of the polysialic acid prevents NCAM
cross-linking of cells.

]]> By: duck http://www.virology.ws/2009/05/04/influenza-virus-attachment-to-cells/comment-page-1/#comment-883 duck Mon, 04 May 2009 20:27:42 +0000 http://www.virology.ws/?p=1308#comment-883 So what is the function of sialic acid (apart from allowing virus infection) - is it useful to us, or just an accident? Why is it there? So what is the function of sialic acid (apart from allowing virus infection) – is it useful to us, or just an accident? Why is it there?

]]>