CpG寡脱氧核苷酸作为人用疫苗佐剂的初步研究

CpG-ODN is a potential candidate adjuvant for human vaccines

目的 研究活化人免疫细胞的CpG寡脱氧核苷酸 (CpG ODN)在动物模型中的疫苗佐剂活性。方法 通过体外试验确定研究人CpG ODN的动物模型 ,评价人CpG ODN在动物模型中对HBsAg的疫苗佐剂活性。结果 CpG2 0 0 6等含有 5′GTCGTT 3′基元的人CpG ODN能够活化小鼠脾细胞分泌IgM和IFN γ ,而CpGT7等含有 5′GTCGTC 3′基元的人CpG ODN对小鼠活性很弱 ,具有较强人特异性 ,但两类序列均能够较好活化恒河猴B细胞。以上结果提示小鼠和恒河猴可能用作研究人CpG ODN的动物模型。在BALB/c小鼠中含有 5′GTCGTT 3′基元的序列能够显著提高抗 HBs总抗体、IgG1和IgG2a亚型抗体水平 ,而含有 5′GTCGTC 3′基元的序列作用稍弱 ,但两者均能够显著逆转Al(OH) 3 对Th1类免疫应答的抑制作用 ,使IgG2a/IgG1从 0 .0 14提高到 1左右。然而在恒河猴体内的疫苗佐剂活性较弱 ,CpGT7能够使特异性抗体滴度提高 2倍 ,而CpG2 0 0 6没有作用。结论 动物模型结果表明CpG

Objective To evaluate the adjuvanticity of CpG ODN for human vaccines in animal models. Methods To find suitable animal models, the human CpG ODN were examined for their in vitro immunostimulatory activities for murine and Rhesus monkey immune cells. Then by using recombinant HBsAg as a model antigen, the adjuvanticity of human CpG ODN was evaluated in the animal models. Results Rhesus monkey B cells responded well to all the human CpG ODN, similarly as that of human B cells. In contrast, only the human CpG ODN with the CpG motif 5′GTCGTT 3′(CpG2006 etc)could induce murine splenocytes to secret IgM and IFN γ, while those with the CpG motif 5′GTCGTC 3′ (CpGT7 etc) had less or no effects. The results suggested that Rhesus monkeys and mice could be used as animal models to evaluate the in vivo activities of different human CpG ODN. Immunized with HBsAg combined with various human CpG ODN, the mice elicited a stronger Th1 humoral immunity. Consistent with the in vitro findings, CpG ODN with the CpG motif 5′GTCGTT 3′ were more potent than those with the CpG motif 5′GTCGTC 3′. But of note, all the sequences had the same ability for modulation of Th1/ Th2 immune response, with the ratio of IgG2a/IgG1 around 1. However, human CpG ODN had less adjuvanticity for HBsAg in Rhesus monkeys;only CpGT7 increased the antibody titers by 2 times, while CpG2006 had no effect. Conclusion The preliminary results derived from animal models showed that CpG ODN was a potential candidate Th1 adjuvant for human vaccines.