Figure 3.

Nitrite production is increased in stimulated macrophages (Mφ) from tartrate-resistant acid phosphatase (TRAP)-deficient mice. Mφ obtained from peritoneum (a) and bone marrow (b) were stimulated with lipopolysaccharide (LPS) (1 µg/ml), with or without interferon-γ (IFN-γ) (100 U/ml) or tumour necrosis factor-α (TNF-α) (500 U/ml). Nitrite was determined in cell supernatants by the Griess reaction, as described in the Materials and Methods. The nitric oxide synthase inhibitor, N-monomethyl-l-arginine (l-NMMA) (300 µm), was added to ensure that the nitrite measured was derived from nitric oxide synthase. The data are representative of at least four experiments and expressed as mean ± SEM values. *P < 0·05.