Ligation of Siglec-8: A selective mechanism for induction of human eosinophil apoptosis

Esra Nutku, Hideyuki Aizawa, Sherry A. Hudson, Bruce S. Bochner

Research output: Contribution to journalArticlepeer-review


Sialic acid binding immunoglobulin-like lectin 8 (Siglec-8), which exists in 2 isoforms including one possessing cytoplasmic tyrosine motifs, is expressed only on human eosinophils, basophils, and mast cells. Until now, its function was unknown. Here we define a novel function of Siglec-8 on eosinophils. Siglec-8 crosslinking with antibodies rapidly generated caspase-3-like activity and reduced eosinophil viability through induction of apoptosis. The pancaspase inhibitor benzyloxycarbonyl (Cbz)-Val-Ala-Asp-(Ome)-fluoromethyl ketone (zVAD-FMK) completely blocked this response, implicating caspases in Siglec-8 cross-linking-induced apoptosis. Eosinophil survival-promoting cytokines such as interleukin 5 (IL-5) and granulocyte-macrophage colonystimulating factor (GM-CSF) failed to block apoptosis and instead enhanced the sensitivity of eosinophils to undergo apoptosis in response to Siglec-8 antibody. Siglec-8 activation may provide a useful therapeutic approach to reduce numbers of eosinophils (and perhaps basophils and mast cells) in disease states where these cells are important.

Original languageEnglish (US)
Pages (from-to)5014-5020
Number of pages7
Issue number12
StatePublished - Jun 15 2003

ASJC Scopus subject areas

  • Biochemistry
  • Immunology
  • Hematology
  • Cell Biology

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