Characterization of Siglec-8 Expression on Lavage Cells after Segmental Lung Allergen Challenge

Mats W. Johansson*, Elizabeth A. Kelly, Christopher L. Nguyen, Nizar N. Jarjour, Bruce Scott Bochner

*Corresponding author for this work

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Background: Siglec-8 is present at a high level on human blood eosinophils and low level on blood basophils. Engagement of Siglec-8 on blood eosinophils causes its internalization and results in death. Siglec-8 is a potential therapeutic target in eosinophilic asthma. Objectives: The aim of this study was to determine Siglec-8 levels on eosinophils and basophils recruited during lung inflammation. Method: We analyzed surface Siglec-8 by flow cytometry on cells obtained by bronchoalveolar lavage (BAL) 48 h after segmental lung allergen challenge of human subjects with mild allergic asthma and used confocal microscopy to compare Siglec-8 distribution on BAL and blood eosinophils. Results: Like their blood counterparts, BAL eosinophils had high unimodal surface Siglec-8, while BAL basophils had lower but detectable surface Siglec-8. BAL macrophages, monocytes, neutrophils, and plasmacytoid dendritic cells did not express surface Siglec-8. Microscopy of freshly isolated blood eosinophils demonstrated homogeneous Siglec-8 distribution over the cell surface. Upon incubation with IL-5, Siglec-8 on the surface of eosinophils became localized in patches both at the nucleopod tip and at the opposite cell pole. BAL eosinophils also had a patchy Siglec-8 distribution. Conclusions: We conclude that 48 h after segmental allergen challenge, overall levels of Siglec-8 expression on airway eosinophils resemble those on blood eosinophils, but with a patchier distribution, a pattern consistent with activation. Thus, therapeutic targeting of Siglec-8 has the potential to impact blood as well as lung eosinophils, which may be associated with an improved outcome in eosinophilic lung diseases.

Original languageEnglish (US)
Pages (from-to)16-28
Number of pages13
JournalInternational archives of allergy and immunology
Volume177
Issue number1
DOIs
StatePublished - Aug 1 2018

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Sialic Acid Binding Immunoglobulin-like Lectins
Therapeutic Irrigation
Allergens
Eosinophils
Lung
Bronchoalveolar Lavage
Basophils
Asthma

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

Cite this

Johansson, Mats W. ; Kelly, Elizabeth A. ; Nguyen, Christopher L. ; Jarjour, Nizar N. ; Bochner, Bruce Scott. / Characterization of Siglec-8 Expression on Lavage Cells after Segmental Lung Allergen Challenge. In: International archives of allergy and immunology. 2018 ; Vol. 177, No. 1. pp. 16-28.
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title = "Characterization of Siglec-8 Expression on Lavage Cells after Segmental Lung Allergen Challenge",
abstract = "Background: Siglec-8 is present at a high level on human blood eosinophils and low level on blood basophils. Engagement of Siglec-8 on blood eosinophils causes its internalization and results in death. Siglec-8 is a potential therapeutic target in eosinophilic asthma. Objectives: The aim of this study was to determine Siglec-8 levels on eosinophils and basophils recruited during lung inflammation. Method: We analyzed surface Siglec-8 by flow cytometry on cells obtained by bronchoalveolar lavage (BAL) 48 h after segmental lung allergen challenge of human subjects with mild allergic asthma and used confocal microscopy to compare Siglec-8 distribution on BAL and blood eosinophils. Results: Like their blood counterparts, BAL eosinophils had high unimodal surface Siglec-8, while BAL basophils had lower but detectable surface Siglec-8. BAL macrophages, monocytes, neutrophils, and plasmacytoid dendritic cells did not express surface Siglec-8. Microscopy of freshly isolated blood eosinophils demonstrated homogeneous Siglec-8 distribution over the cell surface. Upon incubation with IL-5, Siglec-8 on the surface of eosinophils became localized in patches both at the nucleopod tip and at the opposite cell pole. BAL eosinophils also had a patchy Siglec-8 distribution. Conclusions: We conclude that 48 h after segmental allergen challenge, overall levels of Siglec-8 expression on airway eosinophils resemble those on blood eosinophils, but with a patchier distribution, a pattern consistent with activation. Thus, therapeutic targeting of Siglec-8 has the potential to impact blood as well as lung eosinophils, which may be associated with an improved outcome in eosinophilic lung diseases.",
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Characterization of Siglec-8 Expression on Lavage Cells after Segmental Lung Allergen Challenge. / Johansson, Mats W.; Kelly, Elizabeth A.; Nguyen, Christopher L.; Jarjour, Nizar N.; Bochner, Bruce Scott.

In: International archives of allergy and immunology, Vol. 177, No. 1, 01.08.2018, p. 16-28.

Research output: Contribution to journalArticle

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T1 - Characterization of Siglec-8 Expression on Lavage Cells after Segmental Lung Allergen Challenge

AU - Johansson, Mats W.

AU - Kelly, Elizabeth A.

AU - Nguyen, Christopher L.

AU - Jarjour, Nizar N.

AU - Bochner, Bruce Scott

PY - 2018/8/1

Y1 - 2018/8/1

N2 - Background: Siglec-8 is present at a high level on human blood eosinophils and low level on blood basophils. Engagement of Siglec-8 on blood eosinophils causes its internalization and results in death. Siglec-8 is a potential therapeutic target in eosinophilic asthma. Objectives: The aim of this study was to determine Siglec-8 levels on eosinophils and basophils recruited during lung inflammation. Method: We analyzed surface Siglec-8 by flow cytometry on cells obtained by bronchoalveolar lavage (BAL) 48 h after segmental lung allergen challenge of human subjects with mild allergic asthma and used confocal microscopy to compare Siglec-8 distribution on BAL and blood eosinophils. Results: Like their blood counterparts, BAL eosinophils had high unimodal surface Siglec-8, while BAL basophils had lower but detectable surface Siglec-8. BAL macrophages, monocytes, neutrophils, and plasmacytoid dendritic cells did not express surface Siglec-8. Microscopy of freshly isolated blood eosinophils demonstrated homogeneous Siglec-8 distribution over the cell surface. Upon incubation with IL-5, Siglec-8 on the surface of eosinophils became localized in patches both at the nucleopod tip and at the opposite cell pole. BAL eosinophils also had a patchy Siglec-8 distribution. Conclusions: We conclude that 48 h after segmental allergen challenge, overall levels of Siglec-8 expression on airway eosinophils resemble those on blood eosinophils, but with a patchier distribution, a pattern consistent with activation. Thus, therapeutic targeting of Siglec-8 has the potential to impact blood as well as lung eosinophils, which may be associated with an improved outcome in eosinophilic lung diseases.

AB - Background: Siglec-8 is present at a high level on human blood eosinophils and low level on blood basophils. Engagement of Siglec-8 on blood eosinophils causes its internalization and results in death. Siglec-8 is a potential therapeutic target in eosinophilic asthma. Objectives: The aim of this study was to determine Siglec-8 levels on eosinophils and basophils recruited during lung inflammation. Method: We analyzed surface Siglec-8 by flow cytometry on cells obtained by bronchoalveolar lavage (BAL) 48 h after segmental lung allergen challenge of human subjects with mild allergic asthma and used confocal microscopy to compare Siglec-8 distribution on BAL and blood eosinophils. Results: Like their blood counterparts, BAL eosinophils had high unimodal surface Siglec-8, while BAL basophils had lower but detectable surface Siglec-8. BAL macrophages, monocytes, neutrophils, and plasmacytoid dendritic cells did not express surface Siglec-8. Microscopy of freshly isolated blood eosinophils demonstrated homogeneous Siglec-8 distribution over the cell surface. Upon incubation with IL-5, Siglec-8 on the surface of eosinophils became localized in patches both at the nucleopod tip and at the opposite cell pole. BAL eosinophils also had a patchy Siglec-8 distribution. Conclusions: We conclude that 48 h after segmental allergen challenge, overall levels of Siglec-8 expression on airway eosinophils resemble those on blood eosinophils, but with a patchier distribution, a pattern consistent with activation. Thus, therapeutic targeting of Siglec-8 has the potential to impact blood as well as lung eosinophils, which may be associated with an improved outcome in eosinophilic lung diseases.

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