IL-13 released by and localized in human basophils.
We and others have shown that human basophils can synthesize and release IL-4. However, IL-13, a cytokine that closely resembles IL-4, has not hitherto been described as a basophil product. The production of IL-13 by basophils was demonstrated by immunocytochemistry. Approximately 70% of basophils stimulated with anti-FcepsilonRIalpha (antibody to the alpha subunit of IgE receptor type I) stained for IL-13. Under similar experimental conditions, mononuclear cells failed to stain for IL-13. The cytokine was localized to basophilic granules by electron microscopic examination of immunogold staining. The secretion of IL-13 into the culture supernatant was assayed by ELISA. Kinetic studies showed detectable IL-13 release at 3 h, which steadily increased up to 24 h. This is significantly different from the kinetics of basophil histamine and IL-4 release. IL-13 production was also observed upon stimulation with anti-IgE, anti-FcepsilonRIalpha, IL-3, and A23187 in a dose-dependent manner. PBMC, neutrophils, and eosinophils isolated from the same donors did not release IL-13 after anti-IgE stimulation. The anti-IgE-induced basophil IL-13 synthesis could be enhanced by IL-3 preincubation (with and without IL-3 preincubation, anti-IgE-induced IL-13 production was 227 +/- 99 and 42 +/- 13 pg/10(6) basophils, respectively). PBMC produced a significant amount of IL-1 3 upon stimulation with PHA, but a low level of IL-13 in response to A23187 and/or PMA. Eosinophils and neutrophils did not produce IL-13 when cultured with A23187, IL-5, and anti-FcepsilonRIalpha. This is the first demonstration of IL-1 3 production by basophils. Our data suggest that basophils, in addition to secreting mediators, can represent an important source of proallergic cytokines.
Li
H
H
Department of Internal Medicine, Division of Allergy and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA.
Sim
T C
TC
Alam
R
R
D001491:Basophils / Q000378:metabolism*; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D004804:Eosinophils / Q000378:metabolism; D006801:Humans; D006967:Hypersensitivity; D007150:Immunohistochemistry; D018793:Interleukin-13 / Q000378:metabolism*; D007377:Interleukin-3 / Q000494:pharmacology; D015847:Interleukin-4 / Q000096:biosynthesis; D009504:Neutrophils / Q000378:metabolism; D017455:Receptors, IgE / Q000378:metabolism
D018793:Interleukin-13; D007377:Interleukin-3; D017455:Receptors, IgE; D015847:Interleukin-4