Functional up-regulation of the β2 integrin MAC-1 (CD11b/CD18) by an endogenous lipid mediator in human neutrophils and HL-60 cells

B. Walzog, K. Klugewitz, D. Schuppan, R. Nuck, K. Ley, P. Gaehtgens

Research output: Contribution to journalArticlepeer-review

Abstract

The ß2 integrins (CD11/CD18) play a key role in the adhesion of human neutrophils to microvascular endothelium, their migration to sites of inflammation, and phagocytosis. In order to exert their functions, ß2 integrins require activation, i.e. a shift in ligand affinity. This functional up-regulation is probably due to a conformational change of the ß2 integrins, but the mechanisms of inside-out signaling which trigger this activation are still under investigation. In the present study, the effect of cellular lipids on the affinity state of ß2 integrins was investigated. Lipids were extracted from human neutrophils and HL-60 cells after stimulation with IL-8 and phorbol ester, respectively. The extracts were purified by anion exchange chromatography and/or HPLC fractionation. The lipid extracts induced the adhesion of neutrophils to fibrinogen and the binding of C3bi-coated zymosan-particles by purified Mac-1 (CD11b/CD18). The integral up-regulating activity was resistant to ester hydrolysis, eluted as one particular HPLC-fraction, and showed an UV and visible spectrum with an absorption maximum of 194 ± 2 nm. Taken together, these data support the concept that activated neutrophils and HL-60 cells generate an endogenous lipid mediator which up-regulates ligand binding activity of ß2 integrins.

Original languageEnglish (US)
Pages (from-to)A117
JournalFASEB Journal
Volume11
Issue number3
StatePublished - 1997
Externally publishedYes

ASJC Scopus subject areas

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics

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