B. Ochensberger et al., HUMAN BLOOD BASOPHILS PRODUCE INTERLEUKIN-13 IN RESPONSE TO IGE-RECEPTOR-DEPENDENT AND IGE-RECEPTOR-INDEPENDENT ACTIVATION, Blood, 88(8), 1996, pp. 3028-3037
Interleukin-13 (IL-13) is a recently discovered immunoregulatory cytok
ine. The cellular sources of IL-13 and the regulation of its expressio
n are largely unknown. Here we show that human basophils produce IL-13
in response to IgE-receptor (IgER) crosslinking, IL-3, IL-3 plus C5a,
but not C5a alone. Human basophils express IL-13 in a restricted mann
er since, apart from IL-4, no other cytokines encoded on the cytokine
gene cluster (IL-3, IL-5, and granulocyte macrophage-colony-stimulatin
g factor [GM-CSF]), are induced. Highest levels of IL-13 are formed af
ter IgE-independent activation leading to a prolonged secretion of IL-
13. The response to IgER-crosslinking is more transient preferentially
inducing IL-4. IL-3 is a unique cytokine regulating IL-13 production
by human basophils: Among a large number of cytokines tested, only IL-
3 is capable of directly inducing IL-13 expression. Furthermore, altho
ugh some IL-13 is produced in response to C5a in the presence of IL-5,
GM-CSF, IGF-1 or IL-1 beta, IL-3 is by far the most effective. IL-13
production was blocked by actinomycin D and cycloheximide and conditio
ns leading to IL-13 release also lead to the induction of IL-13 mRNA.
This study supports an important immunoregulatory role of human blood
basophils, owing to their capacity to simultaneously express IL-13 and
IL-4 in a restricted manner. (C) 1996 by The American Society of Hema
tology.