Monochloramine inhibits phorbol ester-inducible neutrophil respiratory burst activation and T cell interleukin-2 receptor expression by inhibiting inducible protein kinase C activity

Monochloramine derivatives are long lived physiological oxidants produced by neutrophils during the respiratory burst. The effects of chemically prepared monochloramine (NH₂Cl) on protein kinase C (PKC) and PKC-mediated cellular responses were studied in elicited rat peritoneal neutrophils and human Jurkat T cells. Neutrophils pretreated with NH₂Cl (30- 50 μM) showed a marked decrease in the respiratory burst activity induced by phorbol 12-myristate 13-acetate (PMA), winch is a potent PKC activator. These cells, however, were viable and showed a complete respiratory burst upon arachidonic acid stimulation, which induces the respiratory burst by a PKC- independent mechanism. The NH₂Cl-treated neutrophils showed a decrease in both PKC activity and PMA-induced phosphorylation of a 47-kDa protein, which corresponds to the cytosolic factor of NADPH oxidase, p47(phox). Jurkat T cells pretreated with NH₂Cl (20-70 μg) showed a decrease in the expression of the interleukin-2 receptor α chain following PMA stimulation. This was also accompanied by a decrease in both PKC activity and nuclear transcription factor-κB activation, also without loss of cell viability. These results show that NH₂Cl inhibits PKC-mediated cellular responses through inhibition of the inducible PKC activity.