Priming the macrophage respiratory burst with IL-4: Enhancement with TNF-α but inhibition by IFN-γ

Abstract

Pre-exposure to bacterial lipopolysaccharide (LPS) or certain cytokines is known to enhance the ability of murine macrophages to generate a respiratory burst in response to subsequent stimulation, a phenomenon referred to as 'priming'. We report here that the cytokine interleukin-4 (IL-4) can prime murine macrophages. Pretreatment of murine bone marrow-derived macrophages (BMM) with 10 U/ml murine IL-4 for 48 hr was found to enhance the respiratory burst following subsequent stimulation with phorbol myristate acetate (PMA) (10-6 M) or zymosan (1 mg/ml). Human tumour necrosis factor-alpha (TNF-α) (10-9 M) can also prime BMM for an enhanced respiratory burst and the combination of TNF-α and IL..