Figure 8.
Hp(2–20)–induced oxygen radical production and its inhibition by histamine. Superoxide anion production in elutriated monocytes was investigated by isoluminol-amplified CL (a). Cells were treated with histamine (50 μM) or the histamine H2-receptor antagonist ranitidine (50 μM). Data show mean values ± SEM of four separate experiments. (b) Data are NK cell cytotoxicity against K562 target cells. The cells were prepared as described in the legend to Figure 5 and treated with Hp(2–20) (50 μM; filled circles), Hp(2–20) + histamine (50 μM; filled boxes), or Hp(2–20) + histamine + ranitidine (50 μM; filled boxes). Results are expressed as percentage of control, where 100% is the cell lysis percentage of control lymphocytes without monocytes added, and are the mean ± SEM of four separate experiments.