Ka. Yamaoka et Jp. Kolb, LEUKOTRIENE-B(4) INDUCES INTERLEUKIN-5 GENERATION FROM HUMAN T-LYMPHOCYTES, European Journal of Immunology, 23(10), 1993, pp. 2392-2398
Leukotriene B4 (LTB4) has been shown to affect several interleukin (IL
)-linked functions of human lymphocytes. In this study, we investigate
d whether LTB4 regulates IL-5 generation from human T cells and subseq
uently modulates eosinophil functions. Preincubation of T cells with v
ery low concentrations (10(-12) to 10(-8) m) of LTB4 induced concentra
tion-dependent IL-5 production, the event occurring after the first 24
h of cultivation. However, direct action of LTB4 to IL-5 generation i
s strictly dependent on a preincubation with appropriate concentration
of LTB4. In contrast, the stereoisomer of LTB4, 5S, 12S-dihydroxy-6,8
,10,14-eicosatetraenoic acid showed no enhancement of IL-5 production.
IL-5 released from LTB4-primed T cells elicited sustained viability o
f mature eosinophils and reduced the content of eosinophil cationic pr
otein in their crystalloid matrix by degranulation. These data suggest
that LTB4 induces bioactive IL-5 production from T cells and that the
released IL-5 modulates eosinophil functions which might play a cruci
al role in eosinophil-linked allergic inflammatory process.