Activation of human eosinophils by IL-13. Induction of CD69 surface antigen, its relationship to messenger RNA expression, and promotion of cellular viability.
To study the effect of IL-13 on CD69 expression and cell viability in human eosinophils, purified human peripheral blood eosinophils from healthy donors were incubated with increasing concentrations of IL-13. The expression of CD69 was analyzed by flow cytometry (FACS). Surface expression of CD69, which was absent on untreated eosinophils, was induced by IL-13 at concentrations ranging from 1 ng/ml to 1 microgram/ml in a concentration-dependent manner. In contrast, neutrophils expressed CD69 neither spontaneously nor following incubation with IL-13. Semiquantitative reverse transcription-PCR for CD69 mRNA showed constitutive CD69 mRNA expression in purified human eosinophils. Incubation of eosinophils with IL-13 further increased CD69-specific mRNA. Analysis of intracellularly stored CD69 in eosinophils permeabilized with saponin revealed intracellular binding of anti-CD69 Abs in all isolated eosinophils. After stimulation with 100 ng/ml IL-13 for 24 h, the concentration of intracellular CD69 decreased by 41 +/- 9%. Furthermore, IL-13 at a concentration of 100 ng/ml enhanced eosinophil viability, as assessed by propidium iodide staining after 4 days in culture from 8.6 +/- 5.5% in control medium to 50.7 +/- 6.8% following stimulation with IL-13 treatment. The effect of Il-13 on eosinophil viability as well as that on CD69 expression were both neutralized by anti-IL-13 Abs. In conclusion, our results demonstrate that IL-13 specifically activates human eosinophils, as determined by the expression of CD69 cell surface protein and mRNA expression. Furthermore, IL-13 significantly prolongs eosinophil survival in vitro. The data suggest that IL-13 may play a role in the activation of eosinophils.
Luttmann
W
W
Department of Pneumology, Medical University Clinics, Freiburg, Germany.
Knoechel
B
B
Foerster
M
M
Matthys
H
H
Virchow
J C
JC
Kroegel
C
C
D015703:Antigens, CD / Q000096:biosynthesis* / Q000235:genetics; D000945:Antigens, Differentiation, T-Lymphocyte / Q000096:biosynthesis* / Q000235:genetics; D001483:Base Sequence; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004804:Eosinophils / Q000187:drug effects*; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D018793:Interleukin-13 / Q000494:pharmacology*; D037181:Lectins, C-Type; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D012503:Saponins / Q000494:pharmacology; D000099192:CD69 Antigens
D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D018793:Interleukin-13; D037181:Lectins, C-Type; D012333:RNA, Messenger; D012503:Saponins; D000099192:CD69 Antigens