Abstract
Human granulocyte-macrophage colony-stimulating factor (GM-CSF) both stimulates hematopoietic precursor cells to grow as well as enhances the function of mature effector cells, such as neutrophils, eosinophils and macrophages. All of the biological actions of GM-CSF appear to be mediated via binding to a single class of high-affinity receptors present on all responsive cells. Affinity cross-linking experiments demonstrate that the same 98 kDa cross-linked species seen on other GM-CSF-responsive cells is also detected on a choriocarcinoma cell line, JAR. However, JAR cells express significantly increased numbers (10,000 sites/cell) of low-affinity (Kd approximately 1.5 nM) GM receptors. The GM-CSF receptor is a glycoprotein which binds to wheat germ agglutinin-sepharose. It is dramatically downregulated on neutrophils by phorbol esters and formyl-methionyl-leucine-phenylalanine (fMLP), but not by phosphatidylinositol-dependent phospholipase C. GM-CSF primes neutrophils for enhanced response to secondary stimuli, such as ionophore and chemotactic factors. Specifically, GM-CSF enhances 3H-arachidonic acid release, synthesis of leukotriene B4 and platelet activity factor in response to fMLP and the calcium ionophores.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.