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SUMMARY:The evolution of Natural Killer cell receptors: alternative strate
 gies to recognise self and create immune variation - Dr John Hammond\, IAH
 \, Compton
DTSTART:20130206T123000Z
DTEND:20130206T133000Z
UID:TALK41791@talks.cam.ac.uk
CONTACT:Sue Griffin
DESCRIPTION:A comparison of mammalian genomes reveals that the biggest dif
 ferences are between the genes involved in the immune response and reprodu
 ction. Natural killer (NK) cells have fundamental roles in both these biol
 ogical processes and are functionally controlled by variable receptors tha
 t recognise MHC class I molecules. This diverse NK cell receptor and MHC c
 lass I ligand system is therefore subject to multiple and strong selection
  pressures. As a consequence these gene families evolve rapidly and orthol
 ogous genes are often impossible to identify even in closely related speci
 es.\n\nDuring mammalian radiation\, different groups have diversified alte
 rnative NK cell receptor gene families that recognise MHC class I. This is
  a remarkable example of convergent evolution that includes three gene fam
 ilies from two structurally unrelated superfamilies (KIR\, NKG2 and Ly49).
  Higher primates have expanded their KIR genes\; some lower primates have 
 expanded NKG2\, whereas rodents and equids have expanded Ly49. Pinnipeds (
 seals) are unusual\, compared to other mammals and their terrestrial relat
 ives\, in retaining multiple functional NK cell receptors as single copy g
 enes despite possessing a diverse MHC class I repertoire. In contrast\, ca
 ttle have created this variation by expanding all three gene families\; th
 e only species known to have significantly expanded more than one. These a
 lternative genetic strategies illustrate the evolutionary complexity of th
 ese systems\, and present a natural reservoir of immunogenetic diversity t
 o improve disease resistance in livestock species.
LOCATION:Lecture Theatre\, Department of Pathology\, Tennis Court Road
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