Abstract
Some studies have suggested that the Histamine H-2 receptor antagonist, Cimedtidine, may cause a pharmacological blockade of suppressor cells. In animal studies, we looked at the effect of Cimetidine against tumors. Various concentrations of Cimetidine were administered intramuscularly to C3H/He mice, each with a growing MH 134 tumor. As a result, the surviving mice in the group were injected with 100 mg of Cimetidine per kg every 4 days. They were significantly longer than the ones injected with only saline, and, in the 100 mg/kg Cimetidine group, they also showed a significant inhibition of tumor proliferation. We also studied the anti-tumor effect of OK-432; animals were injected i. p. every 2 days and 100 mg/kg of Cimetidine was administered i. m, every 4 days. The OK-432+Cimetidine group had significantly inhibited tumor proliferation in comparison with the other 3 remaining groups : 1) only saline 2) only Cimetidine 3) only OK-432. In addition, the anti-tumor effects of Cimetidine combined Mitomycin C were assessed by measuring the weights of tumor-bearing mice. Mitomycin C+the Cimetidine group significantly inhibited tumor proliferation in comparison to the group given only Mitomycin C. At present, inducing cytotoxic cell generation is the main recourse in immunotherapy, but hereafter, the use of Cimetidine may become popular, as it is a new immunomodulator which inhibits suppressor cells.
