Allergen-specific cytokine polarization protects shetland ponies against culicoides obsoletus-induced insect bite hypersensitivity
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Date
Authors
Meulenbroeks, Chantal
Van der Lugt, Jaco J.
Van der Meide, N.M.A.
Willemse, Ton
Rutten, Victor P.M.G.
Zaiss, Dietmar M.W.
Journal Title
Journal ISSN
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Publisher
Public Library of Science
Abstract
The immunological mechanisms explaining development of an allergy in some individuals
and not in others remain incompletely understood. Insect bite hypersensitivity (IBH) is a
common, seasonal, IgE-mediated, pruritic skin disorder that affects considerable proportions
of horses of different breeds, which is caused by bites of the insect Culicoides obsoletus
(C. obsoletus).We investigated the allergen-specific immune status of individual horses
that had either been diagnosed to be healthy or to suffer of IBH. Following intradermal allergen
injection, skin biopsies were taken of IBH-affected and healthy ponies and cytokine expression
was determined by RT-PCR. In addition, allergen-specific antibody titers were
measured and cytokine expression of in vitro stimulated, allergen-specific CD4 T-cells was
determined. 24 hrs after allergen injection, a significant increase in mRNA expression of the
type-2 cytokine IL-4 was observed in the skin of IBH-affected Shetland ponies. In the skin of
healthy ponies, however, an increase in IFNγ mRNA expression was found. Analysis of allergen-
specific antibody titers revealed that all animals produced allergen-specific antibodies,
and allergen-specific stimulation of CD4 T-cells revealed a significant higher
percentage of IFNγ-expressing CD4 T-cells in healthy ponies compared to IBH-affected ponies.
These data indicate that horses not affected by IBH, in contrast to the so far established
dogma, are not immunologically ignorant but have a Th1-skewed allergen-specific
immune response that appears to protect against IBH-associated symptoms. To our knowledge
this is the first demonstration of a natural situation, in which an allergen-specific immune
skewing is protective in an allergic disorder.
Description
S1 Table. Primers and probes as well as the PCR conditions used for qRT-PCR .
S2 Table. Histological scores from healthy and IBH-affected ponies at different time points after allergen injection. Paraffin-embedded biopsies were cut into sections and stained with either haematoxylin-eosin (HE). Sections were graded according to a semi-quantitative grading system (0 = absent, 1 = minimal, 2 = mild, 3 = moderate, 4 = severe) as previously described 12; average and range between brackets.
S2 Table. Histological scores from healthy and IBH-affected ponies at different time points after allergen injection. Paraffin-embedded biopsies were cut into sections and stained with either haematoxylin-eosin (HE). Sections were graded according to a semi-quantitative grading system (0 = absent, 1 = minimal, 2 = mild, 3 = moderate, 4 = severe) as previously described 12; average and range between brackets.
Keywords
Allergy, Insect bite, Culicoides obsoletus, Horses, Insect bite hypersensitivity (IBH)
Sustainable Development Goals
Citation
Meulenbroeks C, van der Lugt JJ, van der Meide NMA, Willemse T, Rutten VPMG, Zaiss DMW (2015) Allergen-Specific Cytokine Polarization Protects Shetland Ponies against Culicoides obsoletus-Induced Insect Bite Hypersensitivity. PLoS ONE 10(4): e0122090. DOI: 10.1371/journal.pone.0122090.