Fig. 6.
Role of the NADPH oxidase and superoxide in T-cell production of TNF-α. T cells (2 × 105) were cultured on anti-CD3 plates in the presence or absence of the indicated agents. Superoxide was measured using the 1-hydroxy-4-methoxy-2,2,6,6-tetramethylpiperidine spin-probe with electron spin resonance in the absence and presence of the ANG I-converting enzyme inhibitor (A; n = 5). In other studies, T cells from wild-type and p47phox−/− mice were cultured on anti-CD3 plates for 48 h, and the release of TNF-α into the media determined by ELISA (B; n = 6–8). Studies to determine the role of hydrogen peroxide vs. superoxide production by the NADPH oxidase were also performed by treating T cells with either polyethylene glycol-linked catalase (PEG-catalase, 100 U/ml) to scavenge hydrogen peroxide or PEG-superoxide dismutase (PEG-SOD). PEG alone was used as a control (C; n = 8).