OBJECTIVETo study the acute toxicity of C25P polypeptide, a CCR5 antagonist, in mice and its carcinogenic effect in vitro.

METHODSThe acute toxicity of C25P polypeptide in mice was assessed by determining the maximum tolerated dose (MTD). The mice were given C25P at the dose of 3.64 g/kg by tail vein injection, and the control mice received saline (40 ml/kg) injection. The mice were continuously observed for 14 days after the administration and sacrificed on day 14 for routine blood test, examination of the blood biochemistry and pathological examination. The carcinogenicity of C25P polypeptide in vitro was evaluated in cultured cell lines by chromosome aberration test, cell transformation test and non-anchorage dependent growth test.

RESULTSNo mice died following administration of the drug, but 3 mice showed mild adverse reactions. The rats in both groups showed an increase in the body weight at a comparable rate. GPT increased and ALP decreased significantly in C25P polypeptide group (P<0.05). Most of the organs of the rats treated with in C25P polypeptide remained normal, but 3 mice showed pathologies in the lung, spleen and liver. Chromosome aberration test, cell transformation test and non-anchorage-dependent growth test all yielded negative results for C25P polypeptide.

CONCLUSIONC25P polypeptide is a low-toxicity drug that produces no apparent acute toxicity in mice or obvious carcinogenicity in vitro.