Oxygen uptake associated with Sendai-virus-stimulated chemiluminescence in rat thymocytes contains a significant non-mitochondrial component

Abstract

Sendai virus (150 haemagglutinating units/10(6) cells) stimulates rat thymocytes incubated in medium containing 5 mM-glucose at 37 degrees C to produce luminol-dependent chemiluminescence and a simultaneous increase in O2 consumption of 40%. Stimulation of thymocytes with Sendai virus is accompanied by reduction of exogenous acetylated ferricytochrome c, which is inhibited by superoxide dismutase, and the quantitative conversion of ferricyanide to ferrocyanide, which is not. Replacement of air in the gas space with N2 inhibits the chemiluminescent response by 97% but does not prevent the virus-stimulated reduction of ferricyanide. The non-permeant ferricyanide anion (2 mM) also inhibits the chemiluminescent response to Sendai virus, its accompanying 'extra' O2 uptake and the reduction of acetylated ferricytochrome c without affecting the basal respiration of the cells. Thymocytes in which the basal O2 consumption has been stimulated maximally with dinitrophenol (10 microM) or inhibited completely with antimycin A (0.1 microM) respond to Sendai virus with an additional increment of ferricyanide-inhibitable O2 consumption. The chemiluminescent response to virus is not inhibited by concentrations of antimycin A that block the basal respiration completely. We suggest that a portion of the increased O2 uptake induced by Sendai virus is involved in the non-mitochondrial reduction of O2 to O2- at the cell surface where the non-permeant ferricyanide anion inhibits O2-. formation by acting as an alternative high-affinity electron acceptor to O2.

The NOX Family of ROS-Generating NADPH Oxidases: Physiology and Pathophysiology

“…Thymocytes and peripheral T cells generate ROS through an NADPH oxidase-like system (241,420,480,667,705,959). One study using a mixed culture of primary lymph node cells concluded that NOX2 is not a relevant source of ROS generation by T cells (907).…”

Regulation of reactive oxygen species (ROS) production by C18 fatty acids in Jurkat and Raji cells

“…Generation of moderate amounts of ROS (reactive oxygen species) by several non-phagocytic leucocytes, including B-lymphocyte cell lines [1][2][3][4], human tonsillar B-lymphocytes [5], thymocytes [6,7], human NK (natural killer) cells [8,9], human peripheral T-lymphocytes [10] and T-lymphocyte cell lines [11], has been described.…”

The radiosensitivity of rat thymocytes

“…Thymocytes were obtained from male rats of a Wistar strain (100-200 g body wt.) (Kolbuch-Braddon et al, 1984) and suspended in phosphate-buffered saline, pH 7.4 (Cohen et al, 1980), containing 5 mM-glucose. Preliminary experiments showed that Ca2+ detectably but not significantly increased 02 uptake; 0.5 mM-Ca2+ was therefore normally present in the buffered saline (cf.…”

“…The discovery of an antimycin-and cyanide-insensitive NADPH oxidase in the plasma membrane of various white cell types (Goldstein et al, 1977;Babior et al, 1981;Fantone & Ward, 1982) including rat thymocytes (Kolbuch-Braddon et al, 1984), suggested that the presence of this enzyme system, fortuitously or otherwise, in nuclear preparations might have accounted for the 02 uptake observed earlier. Consistent with this view, the present paper shows that a plasma-membrane-associated NADPH oxidase in rat thymocytes is inhibited by ionizing radiation at levels of exposure which are lethal for small lymphocytes.…”