Insulin-like growth factors enhance phagocytosis by human neutrophils in vitro.
Polymorphonuclear neutrophils (PMNs) were isolated from human blood, and PMN phagocytosis was assessed by measuring the chemiluminescence (CL) response in the presence of ZAP (opsonized zymosin particles containing luminol). The administration of 6.5 nM of insulin-like growth factor I (IGF-I), des(1-3)-IGF-I, IGF-II or insulin to PMNs for 20 min resulted in significant increases of the CL response for all test preparations. Des(1-3)-IGF-I, a truncated IGF-I with low affinity binding to IGF binding proteins (IGFBPs), was the most potent CL stimulator. The CL production evoked by 6.5 nM of des(1-3)-IGF-I was inhibited significantly by both 0.25 and 1.0 nM of EGTA (Ca2+ chelator), or 10 microM nifedipine (Ca2+ channel inhibitor), pertussis toxin (0.05 and 1.0 micrograms/ml) or cholera toxin (5 micrograms/ml). These results suggest that IGF-I and its homologues are potent stimulators of phagocytosis and that this action is modulated by IGFBP, and may require extracellular Ca2+ and/or IGF-I receptor G-protein coupling.
Jin
G F
GF
Department of Microbiology, University of Texas Medical Branch, Galveston 77555-1019.
Guo
Y S
YS
Ball
C
C
Houston
C W
CW
D000328:Adult; D000595:Amino Acid Sequence; D002772:Cholera Toxin / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007334:Insulin-Like Growth Factor I / Q000502:physiology; D008163:Luminescent Measurements; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000276:immunology*; D009543:Nifedipine / Q000494:pharmacology; D010446:Peptide Fragments / Q000502:physiology; D037342:Pertussis Toxin; D010587:Phagocytosis / Q000502:physiology*; D013002:Somatomedins / Q000276:immunology*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D010446:Peptide Fragments; D013002:Somatomedins; D010566:Virulence Factors, Bordetella; C058957:insulin-like growth factor 1, des-(1-3)-; D004533:Egtazic Acid; D007334:Insulin-Like Growth Factor I; D002772:Cholera Toxin; D037342:Pertussis Toxin; D009543:Nifedipine