Effects of reactive nitrogen scavengers on NK-cell-mediated killing of K562 cells

Abstract

This study explored the effects of reactive nitrogen metabolites (RNMS) on natural-killer- (NK-) cell-mediated killing of K562 cells and the influence of RNM scavengers, such as tiopronin (TIP), glutamylcysteinylglycine (GSH), and histamine dihydrochloride (DHT), on reversing the suppressing effect of RNM. We administered exogenous and endogenous RNM in the NK + K562 culture system and then added RNM scavengers. The concentrations of RNM, TNF-β and IFN-γ, and NK-cell cytotoxicity (NCC) and the percentage of living NK cells were then examined. We found that both exogenous and endogenous RNM caused the KIR to decrease (P < 0.01); however, RNM scavengers such as TIP and GSH rescued this phenomenon dose dependently. In conclusion, our data suggests that RNM scavengers such as TIP and GSH enhance the antineoplasmic activity of NK cells.

Figure 1

The effect of different dosages of RNM scavengers on the activity of NK cells. With an increase of the dosage, the groups treated with TIP and GSH decreased the production of RNM and increased the levels of TNF-γ, IFN-β and NCC significantly (P < 0.05). However, each group of DHT could not eliminate RNM (P > 0.05).

Figure 2

The effect of different combinations of RNM scavengers on the activity of NK cells. Different combinations of RNM scavengers did not enhance the antineoplasmic activity of NK cells.