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MHC-I Affects Infection Intensity but Not Infection Status with a Frequent Avian Malaria Parasite in Blue Tits

  • Helena Westerdahl
  • Martin Stjernman
  • Lars Råberg
  • Mimi Lannefors
  • Jan-Åke Nilsson
Publishing year: 2013
Language: English
Publication/Series: PLoS ONE
Volume: 8
Issue: 8
Document type: Journal article
Publisher: Public Library of Science

Abstract english

Host resistance against parasites depends on three aspects: the ability to prevent, control and clear infections. In vertebrates the immune system consists of innate and adaptive immunity. Innate immunity is particularly important for preventing infection and eradicating established infections at an early stage while adaptive immunity is slow, but powerful, and essential for controlling infection intensities and eventually clearing infections. Major Histocompatibility Complex (MHC) molecules are central in adaptive immunity, and studies on parasite resistance and MHC in wild animals have found effects on both infection intensity (parasite load) and infection status (infected or not). It seems MHC can affect both the ability to control infection intensities and the ability to clear infections. However, these two aspects have rarely been considered simultaneously, and their relative importance in natural populations is therefore unclear. Here we investigate if MHC class I genotype affects infection intensity and infection status with a frequent avian malaria infection Haemoproteus majoris in a natural population of blue tits Cyanistes caeruleus. We found a significant negative association between a single MHC allele and infection intensity but no association with infection status. Blue tits that carry a specific MHC allele seem able to suppress H. majoris infection intensity, while we have no evidence that this allele also has an effect on clearance of the H. majoris infection, a result that is in contrast with some previous studies of MHC and avian malaria. A likely explanation could be that the clearance rate of avian malaria parasites differs between avian malaria lineages and/or between avian hosts.


  • Biological Sciences


  • Malaria in birds
  • Avian MHC genes
  • CAnMove
  • Molecular Ecology and Evolution Lab
  • ISSN: 1932-6203
Helena Westerdahl
E-mail: helena [dot] westerdahl [at] biol [dot] lu [dot] se

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+46 46 222 36 69



Research group

Molecular Ecology and Evolution Lab


Doctoral students and postdocs

Research fellows


Luz Garcia-Longoria

PhD students, main supervisor

Samantha Mellinger

PhD students, assistant supervisor

Gustaf Ekelund Ugge

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