ABSTRACT
The generation and activity of serum neuralizing antibody in cynomolgus monkeys and SD rats undergoing long-term toxicity study with antitumor peptides HM-3 were investigated.The rats were administered intravenously with HM-3 at doses of 4.5 mg/kg,13.5 mg/kg,and 40.5 mg/kg for 6 months,and the cynomolgus monkeys were administrated intravenously with HM-3 at doses of 3 mg/kg,9 mg/kg and 27 mg/kg for 6 months,respectively.Anti-HM-3 antibodies and their neutralizing activities in serum samples taken every month after the administrations were determined by ELISA and cell migration assay,respectively.During the long-term administrations,anti-HM-3 antibodies were generated in some SD rats at high and moderate dose groups,and the antibody-neutralizing activities could be detected in a number of these samples (P ＜0.05).However,activity could be detected in very few monkeys (P ＜ 0.05),and the antibody titers were not correlated with the neutralizing activities.Therefore,we conclude that the antigenicity of HM-3 was low,but after long-term administration at high dose,low affinity neutralizing antibody could be generated in small number of samples.