TY - JOUR
T1 - Cytokine-induced protein tyrosine phosphorylation is essential for cytokine priming of human eosinophils
AU - Van Bruggen, Tjomme Der
AU - Kanters, Deon
AU - Tool, Anton T.J.
AU - Raaijmakers, Jan A.M.
AU - Lammers, Jan Willem J.
AU - Verhoeven, Arthur J.
AU - Koenderman, Leo
PY - 1998/1/1
Y1 - 1998/1/1
N2 - Background: Human eosinophils are strongly modulated by the eosinophilotrophic cytokines IL-5, IL-3, and granulocyte-macrophage colony- stimulating factor (GM-CSF). A clear intracellular effect of these cytokines is the induction of tyrosine phosphorylation of multiple cellular substrates. However, the relevance of tyrosine phosphorylation for eosinophil functioning has not been established. Objective: In this study we have investigated dose- response and time curves of IL-5-, IL-3-, and GM-CSF-induced tyrosine phosphorylation in eosinophils. Moreover, we have evaluated the importance of IL-5-induced tyrosine phosphorylation for priming of human eosinophils. Methods: Cytokine-induced tyrosine phosphorylation was monitored on western blot with an antiphosphotyrosine antibody (4G10). To probe the relevance of tyrosine phosphorylation for priming, eosinophils were primed with IL-5 in the presence of the tyrosine kinase inhibitor herbimycin A. Platelet activating factor (PAF) was used as a control priming agent. Subsequently, the eosinophils were incubated with serum-treated zymosan (STZ) to activate the respiratory burst. Binding of STZ was determined by FACS analysis. Results: IL-5-, IL-3-, and GM-CSF-induced tyrosine phosphorylation was found at concentrations that primed eosinophil effector mechanism (median effective dose values: ≃ 5.10-11 mol/L, ≃5.10-10 mol/L, and ≃5. 10-12 mol/L for IL-5, IL-3, and GM-CSF, respectively). Cytokine-induced tyrosine phosphorylation was transient with an optimum value at 15 minutes. IL-5 priming of STZ-induced activation of the respiratory burst was blocked by herbimycin A, whereas PAF still primed this response. In fact, herbimycin A inhibited IL-5 priming of STZ binding to human eosinophils. On the other hand, PAF priming of STZ binding was not affected by herbimycin A. Both IL- 5-induced and PAF-induced tyrosine phosphorylation were inhibited by herbimycin A. Conclusion: These data demonstrate for the first time that IL- 5 priming of opsonized particle-induced responses is mediated by tyrosine kinase activity in human eosinophils.
AB - Background: Human eosinophils are strongly modulated by the eosinophilotrophic cytokines IL-5, IL-3, and granulocyte-macrophage colony- stimulating factor (GM-CSF). A clear intracellular effect of these cytokines is the induction of tyrosine phosphorylation of multiple cellular substrates. However, the relevance of tyrosine phosphorylation for eosinophil functioning has not been established. Objective: In this study we have investigated dose- response and time curves of IL-5-, IL-3-, and GM-CSF-induced tyrosine phosphorylation in eosinophils. Moreover, we have evaluated the importance of IL-5-induced tyrosine phosphorylation for priming of human eosinophils. Methods: Cytokine-induced tyrosine phosphorylation was monitored on western blot with an antiphosphotyrosine antibody (4G10). To probe the relevance of tyrosine phosphorylation for priming, eosinophils were primed with IL-5 in the presence of the tyrosine kinase inhibitor herbimycin A. Platelet activating factor (PAF) was used as a control priming agent. Subsequently, the eosinophils were incubated with serum-treated zymosan (STZ) to activate the respiratory burst. Binding of STZ was determined by FACS analysis. Results: IL-5-, IL-3-, and GM-CSF-induced tyrosine phosphorylation was found at concentrations that primed eosinophil effector mechanism (median effective dose values: ≃ 5.10-11 mol/L, ≃5.10-10 mol/L, and ≃5. 10-12 mol/L for IL-5, IL-3, and GM-CSF, respectively). Cytokine-induced tyrosine phosphorylation was transient with an optimum value at 15 minutes. IL-5 priming of STZ-induced activation of the respiratory burst was blocked by herbimycin A, whereas PAF still primed this response. In fact, herbimycin A inhibited IL-5 priming of STZ binding to human eosinophils. On the other hand, PAF priming of STZ binding was not affected by herbimycin A. Both IL- 5-induced and PAF-induced tyrosine phosphorylation were inhibited by herbimycin A. Conclusion: These data demonstrate for the first time that IL- 5 priming of opsonized particle-induced responses is mediated by tyrosine kinase activity in human eosinophils.
KW - Binding
KW - Eosinophils
KW - Herbimycin A
KW - IL-5
KW - Platelet activating factor
KW - Priming
KW - Respiratory burst
KW - Serum-treated zymosan
KW - Signal transduction
KW - Tyrosine phosphorylation
UR - http://www.scopus.com/inward/record.url?scp=0031913862&partnerID=8YFLogxK
U2 - 10.1016/S0091-6749(98)70200-3
DO - 10.1016/S0091-6749(98)70200-3
M3 - Article
C2 - 9449508
AN - SCOPUS:0031913862
SN - 0091-6749
VL - 101
SP - 103
EP - 109
JO - Journal of Allergy and Clinical Immunology
JF - Journal of Allergy and Clinical Immunology
IS - 1
ER -