These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Cross-linking of CD18 primes human neutrophils for activation of the respiratory burst in response to specific stimuli: implications for adhesion-dependent physiological responses in neutrophils.
    Author: Liles WC, Ledbetter JA, Waltersdorph AW, Klebanoff SJ.
    Journal: J Leukoc Biol; 1995 Dec; 58(6):690-7. PubMed ID: 7499967.
    Abstract:
    Adhesion is known to prime neutrophils for physiological activation in response to cytokines and other stimuli. We have employed the technique of receptor cross-linking to study the potential role of CD18, the common beta-subunit of the beta 2-integrin family of adhesion molecules, in the regulation of the respiratory burst, as measured by luminol-enhanced chemiluminescence and iodination, in human neutrophils. CD18 cross-linking primed neutrophils to activate the respiratory burst after stimulation with tumor necrosis factor alpha (TNF-alpha) (100 units/mL), formylmethionyl-leucyl-phenylalanine (fMLP) (1 microM), and granulocyte-macrophage colony-stimulating factor (GM-CSF) (1 micrograms/mL), but not granulocyte colony-stimulating factor (G-CSF) (1 micrograms/mL), interferon-gamma (IFN-gamma) (100 U/mL), or phorbol myristate acetate (100 nM). The maximal rate of chemiluminescence induced by fMLP, TNF-alpha, and GM-CSF was enhanced 8-, 6-, and 1.5-fold, respectively, following CD18 cross-linking. Priming of the respiratory burst by direct engagement of CD18 was confirmed in neutrophil-mediated iodination experiments, where iodination induced by TNF-alpha, fMLP, and GM-CSF was increased 15-, 20-, and 7-fold, respectively, by CD18 cross-linking. Immunoblot experiments demonstrated that TNF-alpha-induced tyrosine phosphorylation was both accelerated and more intense in neutrophils after cross-linking of CD18. Major tyrosine phosphoprotein products include proteins with approximate molecular masses of 40, 70, and 110 kDa. Genistein (50 microM), a selective tyrosine kinase inhibitor, reduced the TNF-alpha-stimulated respiratory burst by > 80% whether or not CD18 was cross-linked. These results affirm the importance of CD18 in adhesion-dependent priming of neutrophil functions and demonstrate that CD18 engagement per se is sufficient to prime neutrophils for cytokine-induced signal transduction mediated by tyrosine phosphorylation.
    [Abstract] [Full Text] [Related] [New Search]