Activation of guinea pig eosinophil respiratory burst by leukotriene B₄: role of protein kinase C

Summary— Leukotriene B 4 (LTB 4 ) and the protein kinase C activator, 4‐β‐phorbol dibutyrate (PDBu), both induced a pronounced and concentration‐dependent stimulation of hydrogen peroxide (H 2 O 2 ) generation by purified guinea pig peritoneal eosinophils in the concentration range 1 nM − 1 μM. The LTB 4 response was inhibited competitively by the specific LTB 4 receptor antagonist, U‐75302, with a K B of 25 nM, while the concentration‐response curves for both stimuli were shifted rightwards (3.8‐fold and 2.8‐fold for LTB 4 and PDBu, respectively) by the competitive protein kinase C inhibitor, 1‐ O ‐hexadecyl‐2‐ O ‐methylglycerol at a concentration of 300 μM. LTB 4 appears, therefore, to induce respiratory burst in eosinophils via a receptor‐mediated mechanism involving protein kinase C.