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Enhanced innate immune responses in a brood parasitic cowbird species: degranulation and oxidative burst

Avian Diseases

By:
, , , ,
DOI: 10.1637/10317-080412-Reg.1

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Abstract

We examined the relative effectiveness of two innate immune responses in two species of New World blackbirds (Passeriformes, Icteridae) that differ in resistance to West Nile virus (WNV). We measured degranulation and oxidative burst, two fundamental components of phagocytosis, and we predicted that the functional effectiveness of these innate immune responses would correspond to the species' relative resistance to WNV. The brown-headed cowbird (Molothrus ater), an obligate brood parasite, had previously shown greater resistance to infection with WNV, lower viremia and faster recovery when infected, and lower subsequent antibody titers than the red-winged blackbird (Agelaius phoeniceus), a close relative that is not a brood parasite. We found that cowbird leukocytes were significantly more functionally efficient than those of the blackbird leukocytes and 50% more effective at killing the challenge bacteria. These results suggest that further examination of innate immunity in the cowbird may provide insight into adaptations that underlie its greater resistance to WNV. These results support an eco-immunological interpretation that species like the cowbird, which inhabit ecological niches with heightened exposure to parasites, experience evolutionary selection for more effective immune responses.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Enhanced innate immune responses in a brood parasitic cowbird species: degranulation and oxidative burst
Series title:
Avian Diseases
DOI:
10.1637/10317-080412-Reg.1
Volume
57
Issue:
2
Year Published:
2013
Language:
English
Publisher:
American Association of Avian Pathologists
Contributing office(s):
Patuxent Wildlife Research Center
Description:
5 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
285
Last page:
289