Preliminary Study On The Immunotoxic Effects Of BCG-CpG-DNA

Objective To study the immunotoxic effects of BCG-CpG-DNA and provide the pre-clinical safety evaluation basis for BCG-CpG-DNA.Methods Abnormal toxicity test, Acute toxicity test and 28day toxicity test were used to observe the normal toxicity of BCG-CpG-DNA; Organ coefficients, Lymphotocyte proliferation, cytokines production, analysis of T cells subsets, cytotoxicity assay of NK, levels of anti-double-stranded DNA autoantibody in Peripheral blood were done to evaluate immunotoxic effects of BCG-CpG-DNA.Results (1) Abnormal toxicity test: During the test, the mice of each group had no abnormal appearance and behavior, all of the mice were surviving and put on weight; Major organs had no significant pathological changes.(2) Acute toxicity test: During the test, the mice of each group had no abnormal appearance and behavior, all of the mice were surviving and put on weight; Major organs had no significant pathological changes; the weight of spleens between control group and test groups showed no significant difference(P>0.05).(3) 28day toxicity test:①During the test, the mice of each group had no abnormal appearance and behavior, all of the mice were surviving and put on weight; the weight between control group and test groups showed no significant difference(P>0.05);②Haematological: BCG-CpG-DNA had significant effects on WBC count, absolute lymphocyte, absolute neutrophil ,The changes between control group and test groups had significant difference (P<0.05).③Blood biochemical indexes: Blood biochemical indexes had no obvious changes. The changes between control group and test groups had no significant difference (P>0.05).④Cadaveric and Organ coefficients: Major organs had no significant pathological changes; mice of test groups showed splenomegaly, the weight of spleens between control group and test groups showed significant difference(P<0.05).⑤Local stimulus-response:The injection sides had no obvious pathological changes. (4) Immune function: mice of test groups enhanced proliferation of T cells and B cells , decreased the subsets of CD3+ T cell of middle and high dose group vs control group , higher activity of the cytotoxity of NK, and the ratio of Th1 and Th2 type of cytokine is increased, all results had significant difference between control group and different test groups (P<0.05), and after 3 weeks after final vaccination, almost very change value reversed to nomal status .Conclusions BCG-CpG-DNA had no elicit toxicity damage in Abnormal toxicity test, Acute toxicity test and 28day toxicity test; BCG-CpG-DNA showed no immunotoxic effects in selected dose up to 0.7mg, 1.75mg and 3.5mg , it was safe in the mice.