iayork

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  • July 29, 2010
  • 06:12 AM
  • 3 views

Genetic ironies: Retrovirus version

by iayork in Mystery Rays from Outer Space

I’ve mentioned the APOBEC family before (for example, here and here). They’re a group of mammalian genes that (among other things) protect against retrovirus infection. DIfferent strains of mice have different resistance to retrovirus infection. Some strains are highly resistant, others quite susceptible. At least some of this difference in susceptibility comes down to different [...]... Read more »

  • July 26, 2010
  • 06:11 AM
  • 3 views

Quasispecies thoughts

by iayork in Mystery Rays from Outer Space

Quasispecies theory predicts that slower replicators will be favored if they give rise to progeny that are on average more fit; these populations occupy short, flat regions of the fitness landscape … Flat quasispecies accept mutation without a corresponding effect on fitness … A flat quasispecies with an expansive mutant repertoire can explore vast regions of [...]... Read more »

  • July 12, 2010
  • 06:14 AM
  • 2 views

Short takes: Deep sequencing and HIV drug resistance

by iayork in Mystery Rays from Outer Space

Short comments about what I’ve been reading (besides several hundred influenza articles): Hedskog, C., Mild, M., Jernberg, J., Sherwood, E., Bratt, G., Leitner, T., Lundeberg, J., Andersson, B., & Albert, J. (2010). Dynamics of HIV-1 Quasispecies during Antiviral Treatment Dissected Using Ultra-Deep Pyrosequencing PLoS ONE, 5 (7) DOI: 10.1371/journal.pone.0011345 The whole deep sequencing thing is [...]... Read more »

Hedskog, C., Mild, M., Jernberg, J., Sherwood, E., Bratt, G., Leitner, T., Lundeberg, J., Andersson, B., & Albert, J. (2010) Dynamics of HIV-1 Quasispecies during Antiviral Treatment Dissected Using Ultra-Deep Pyrosequencing. PLoS ONE, 5(7). DOI: 10.1371/journal.pone.0011345  

  • June 22, 2010
  • 06:14 AM
  • 4 views

Dual-specificity T cells and autoimmunity

by iayork in Mystery Rays from Outer Space







TcR interacting with artificial membrane1



Why does autoimmune disease (sometimes) follow viral infection?2
It’s a pretty well-known phenomenon, but a definite answer isn’t yet known — and of course there may not be a single answer, there may be multiple causes. We know that many autoimmune diseases seem to be triggered by some sort of infection [...]... Read more »

  • June 17, 2010
  • 07:29 AM
  • 2 views

Dendritic cells that don’t prime

by iayork in Mystery Rays from Outer Space







Dendritic cells in the skin (Langerhans cells) form a dense network of “sentinels” that act as first line of defense of the immune system.1



There’s a lot of interest in using dendritic cells as vaccines these days.  A paper in PLoS One2 offers a cautionary note.
Dendritic cells (DC) are the main cell type that drive T [...]... Read more »

  • May 20, 2010
  • 07:38 AM
  • 5 views

Cross-protection and flu vaccines

by iayork in Mystery Rays from Outer Space

We know that we need to make new vaccines against influenza each year, because new flu strains arise and spread each year and the previous year’s vaccines don’t give protection against the new strains.  Of course, there’s intense research toward developing cross-protective vaccines.  Ideally, flu vaccines would work like measles vaccines — get a shot [...]... Read more »

  • May 5, 2010
  • 09:27 AM
  • 4 views

Pandemics and publishing (and blogs?)

by iayork in Mystery Rays from Outer Space


A majority of the epidemiological articles on SARS were submitted after the epidemic had ended, although the corresponding studies had relevance to public health authorities during the epidemic.  … although the academic response to the SARS epidemic was rapid, most articles on the epidemiology of SARS were published after the epidemic was over even though [...]... Read more »

  • May 4, 2010
  • 06:46 AM
  • 3 views

Does immune evasion allow rapid HIV progression?

by iayork in Mystery Rays from Outer Space

I was getting a little concerned and distressed by the lack of evidence for any function of viral MHC class I immune evasion. It’s kind of a relief to see articles demonstrating function coming out.
MHC class I is the target for cytotoxic T lymphocytes (CTL), which are generally believed to be pretty important in [...]... Read more »

Stevenson, P., May, J., Smith, X., Marques, S., Adler, H., Koszinowski, U., Simas, J., & Efstathiou, S. (2002) K3-mediated evasion of CD8 T cells aids amplification of a latent γ-herpesvirus. Nature Immunology. DOI: 10.1038/ni818  

Hansen, S., Powers, C., Richards, R., Ventura, A., Ford, J., Siess, D., Axthelm, M., Nelson, J., Jarvis, M., Picker, L.... (2010) Evasion of CD8 T Cells Is Critical for Superinfection by Cytomegalovirus. Science, 328(5974), 102-106. DOI: 10.1126/science.1185350  

  • April 29, 2010
  • 06:14 AM
  • 4 views

Influenza variations, part II

by iayork in Mystery Rays from Outer Space

About 15 minutes after I wrote my last article on influenza variation, I was reading the Journal of Virology  and ran across another paper1 on the same thing, that at least partly addresses some of the missing points in the earlier ones.
To brutally truncate my earlier comments: influenza should generate a huge number of mutants [...]... Read more »

Hoelzer, K., Murcia, P., Baillie, G., Wood, J., Metzger, S., Osterrieder, N., Dubovi, E., Holmes, E., & Parrish, C. (2010) Intrahost Evolutionary Dynamics of Canine Influenza Virus in Naive and Partially Immune Dogs. Journal of Virology, 84(10), 5329-5335. DOI: 10.1128/JVI.02469-09  

Novella, I., Presloid, J., Zhou, T., Smith-Tsurkan, S., Ebendick-Corpus, B., Dutta, R., Lust, K., & Wilke, C. (2010) Genomic Evolution of Vesicular Stomatitis Virus Strains with Differences in Adaptability. Journal of Virology, 84(10), 4960-4968. DOI: 10.1128/JVI.00710-09  

  • April 27, 2010
  • 06:14 AM
  • 8 views

Influenza variations

by iayork in Mystery Rays from Outer Space



Indeed, the amount of HIV diversity within a single infected individual can exceed the variability generated over the course of a global influenza epidemic, the latter of which results in the need for a new vaccine each year. 1

That was said as part of a discussion on HIV vaccines, but let’s think about it from [...]... Read more »

  • April 22, 2010
  • 11:08 AM
  • 6 views

Modeling disease and epidemics

by iayork in Mystery Rays from Outer Space







Fig. 5.  Boundary of the Hopf bifurcation of the endemic steady state … 1




I don’t pretend to be a mathematician or to understand the more complex disease models that are out there, but I do think modeling is an essential way of understanding how to effectively deal with diseases.  A recent paper1 looks at epidemic [...]... Read more »

  • April 20, 2010
  • 09:44 AM
  • 5 views

Rotavirus vaccine and herd immunity

by iayork in Mystery Rays from Outer Space

Rotaviruses are one of the most common causes of gastroenteritis in children.  A new rotavirus vaccine was introduced a few years ago; what impact has it had on disease?

This study confirms on a national scale that the 2008 rotavirus season among children aged <5 years was dramatically reduced compared to pre-RV5 seasons.  …  [...]... Read more »

  • April 15, 2010
  • 06:15 AM
  • 4 views

Living in the future: Mouse TcR clones

by iayork in Mystery Rays from Outer Space







T cell receptor (top) interacting with MHC



It would be nice if I could claim that advances in biology are driven by pure intellectual processes, by hermits on mountaintops achieving new theories through mediation and  deep, pure thoughts. Of course, that’s not the case.  I think its fair to say that many, if not most, of [...]... Read more »

  • April 10, 2010
  • 10:23 AM
  • 4 views

Immune databases and hypotheses

by iayork in Mystery Rays from Outer Space

The folks associated with the IEDB (Immune Epitope Database) have published a very nice and useful guide to all the serious contenders in the immune database field.  1 If you have a particular need, this is an excellent starting point for choosing the appropriate starting point.  (It’s an open access article, too.)
They’ve obviously looked [...]... Read more »

Schatz MM, Peters B, Akkad N, Ullrich N, Martinez AN, Carroll O, Bulik S, Rammensee HG, van Endert P, Holzhütter HG.... (2008) Characterizing the N-terminal processing motif of MHC class I ligands. Journal of immunology (Baltimore, Md. : 1950), 180(5), 3210-7. PMID: 18292545  

  • April 9, 2010
  • 10:19 AM
  • 4 views

Immune evasion versus superinfection

by iayork in Mystery Rays from Outer Space







Human cytomegalovirus-infected cell



A number of viruses, especially herpesviruses, block the MHC class I antigen presentation system. It’s been widely assumed that this is for the obvious reason and that it allows the virus to avoid T cell recognition and elimination. But there’s been an awkward lack of experimental support for that assumption, to [...]... Read more »

Hansen, S., Powers, C., Richards, R., Ventura, A., Ford, J., Siess, D., Axthelm, M., Nelson, J., Jarvis, M., Picker, L.... (2010) Evasion of CD8 T Cells Is Critical for Superinfection by Cytomegalovirus. Science, 328(5974), 102-106. DOI: 10.1126/science.1185350  

  • April 1, 2010
  • 05:30 PM
  • 5 views

Short snorts: Norovirus mutation and evolution

by iayork in Mystery Rays from Outer Space







Norovirus (from J Virol. 82:2079-2088 (2008))



P.G. Wodehouse described his “Blandings Castle” short stories as “the short snorts between the solid orgies”. I usually go for at least one of the solid orgies per week,1 but it’s spring break and I’m hanging out with my kids for the next while.2  So this week and likely next, [...]... Read more »

  • March 26, 2010
  • 06:13 AM
  • 7 views

Wrapping up

by iayork in Mystery Rays from Outer Space

How does a viral genome get into a viral capsid?
There are several strategies, but often the viral capsid is built first, leaving a pore open at one corner; and then the viral genome is fed into that pore, getting neatly wrapped up around scaffolding proteins like a spool of thread.
Herpesviruses follow that strategy, and here’s [...]... Read more »

  • March 24, 2010
  • 06:15 AM
  • 5 views

DAMPs and PAMPs: The enemy within

by iayork in Mystery Rays from Outer Space

The immune system is, by its nature, destructive. Its function is to eliminate problems. Because it’s so destructive, there are many layers on control that constantly check and limit the response. Equally, there are controls that try to ensure that the response doesn’t start until it’s needed.
How does the immune response know when [...]... Read more »

Zhang, Q., Raoof, M., Chen, Y., Sumi, Y., Sursal, T., Junger, W., Brohi, K., Itagaki, K., & Hauser, C. (2010) Circulating mitochondrial DAMPs cause inflammatory responses to injury. Nature, 464(7285), 104-107. DOI: 10.1038/nature08780  

  • March 19, 2010
  • 06:14 AM
  • 6 views

Measles week, Part V: What about the vaccine?

by iayork in Mystery Rays from Outer Space







Measles infection in a brain cell nucleus



Having gone through Parts I, II, III, and IV of Measles week, let’s finish up by asking what this means for measles vaccine.
We know that measles death rates dropped spectacularly well before the vaccine was introduced in 1963 (the first version; a more effective version was released later). [...]... Read more »

MUSCAT, M., BANG, H., WOHLFAHRT, J., GLISMANN, S., & MOLBAK, K. (2009) Measles in Europe: an epidemiological assessment. The Lancet, 373(9661), 383-389. DOI: 10.1016/S0140-6736(08)61849-8  

Filia, A., Brenna, A., Panà, A., Maggio Cavallaro, G., Massari, M., & Ciofi degli Atti, M. (2007) Health burden and economic impact of measles-related hospitalizations in Italy in 2002–2003. BMC Public Health, 7(1), 169. DOI: 10.1186/1471-2458-7-169  

  • March 18, 2010
  • 06:14 AM
  • 5 views

Measles week, part IV: Some of the answers

by iayork in Mystery Rays from Outer Space







Various workers affected by measles punish a god of measles, while a doctor and drugstore keeper try to protect the god from them. (1862



Well, here we are already at Part IV of Measles Week.  Doesn’t time fly? Remember how young we all were, back at Part I, when I raised the question I’m trying [...]... Read more »

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