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SUMMARY:Antigenic variation among dengue viruses - Leah Katzelnick
DTSTART:20140725T160000Z
DTEND:20140725T163000Z
UID:TALK53557@talks.cam.ac.uk
CONTACT:30967
DESCRIPTION:Dengue virus (DENV) infects an estimated 390 million people ea
 ch year\, and of the 96 million individuals who develop an acute systemic 
 illness\, approximately 500\,000 experience potentially life-threatening c
 omplications\, including hemorrhage and shock.  The four genetic DENV type
 s have long been thought to exist as four serotypes\, and the antigenic di
 fferences between the serotypes are believed to have a key role in clinica
 l severity\, epidemic magnitude\, viral evolution\, and the design of effe
 ctive vaccines. However\, investigations that rely on the classification o
 f DENV as serotypes do not fully explain clinical and epidemiological phen
 omena.  Despite this\, antigenic properties are still thought to play a cr
 itical role in the biology of DENV infections.  One hypothesis is that ant
 igenic differences are critical\, but that categorization by serotype is t
 oo coarse a measure.  For example\, differences in epidemic magnitude migh
 t reflect antigenic differences between the particular infecting viruses t
 hat populations experience during sequential epidemics\, but not the serot
 ype of those viruses.  Antigenic variation within and among the DENV types
  may explain why previously successful lineages of a given DENV type becom
 e extinct and are replaced\, why genetically similar viruses can cause bot
 h severe and mild epidemics\, and why a vaccine could protect against one 
 DENV type in one country but not protect against that type in another. We 
 have used antigenic cartography to test the antigenic relationships among 
 panels of diverse DENV isolates to revisit the notion that DENV exists as 
 discrete serotypes. Our antigenic analyses using one-month\, five-month\, 
 and published data from non-human primate and human antisera show that whi
 le DENV isolates are usually located closer to other viruses of the same t
 ype\, some viruses\, both modern and historical\, have greater antigenic r
 esemblance to viruses of a different type than to some viruses of the same
  type.  This finding is a shift in our understanding of the antigenic prop
 erties of DENV.
LOCATION:Tea Room\, Department of Zoology
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