CpG ODN联合HBsAg免疫BALB/c小鼠和HBV转基因C57BL/6J小鼠

目的:探讨人工合成硫代修饰的含CpG基序的寡脱氧核苷酸(ODN)作为佐剂对HBsAg诱导BALB/c和HBV转基因小鼠产生免疫应答的影响. 方法: 用人工合成CpG ODN与血源HBsAg联合免疫BALB/c和HBV转基因C57BL/6J小鼠,采用ELISA方法观察小鼠血清HBsAg及抗-HBs水平,用ELISPOT方法判断CpG ODN对HBsAg免疫小鼠脾T淋巴细胞分泌细胞因子的影响. 结果: CpG ODN联合HBsAg免疫BALB/c小鼠较HBsAg单独注射组同期抗-HBs滴度明显提高,尤其在首次免疫后6、8、12 wk,2组比较差异显著(P<0.05),联合免疫较CpG ODN单独免疫自首次免疫后4 ～16 wk差异显著(P<0.05).与HBsAg,CpG ODN 单独免疫比较,联合免疫能使HBsAg特异性分泌IFN- γ T细胞分别增加3或9倍;CpG ODN,HBsAg联合免疫可诱导转基因小鼠产生抗-HBs,随时间延长,抗体滴度逐渐升高,并能使更多小鼠产生抗体,而单用HBsAg组、CpG ODN组均不能诱导抗-HBs的产生,免疫后各组血清HBsAg浓度较免疫前明显下降(P <0.05),但组间无明显差别(P>0.05),与HBsAg,CpG ODN 单独免疫比较,联合免疫能使HBsAg特异性分泌IFN- γ T细胞分别增加3或11倍. 结论: CpG ODN作为佐剂可增强HBsAg诱导BALB/c小鼠产生体液及细胞免疫应答,CpG ODN ,HBsAg联合免疫可打破HBV转基因小鼠对HBsAg免疫耐受,可望成为慢性乙型肝炎的有效预防和治疗性疫苗.

CpG oligodeoxyribonucleotide with hepatitis B surface antigen (HBsAg) for vaccination in BALB/c and HBV-transgenic mice

AIM: To study the effects of CpG oligodeoxyribonucleotide (ODN) as adjuvant on the immune responses in BALB/c and HBV-transgenic mice with hepatitis B surface antigen (HBsAg). METHODS: BALB/c and HBV transgenic mice were immunized by multiple-site intramuscular injection with HBsAg and phosphorothioate oligodeoxynucleotides containing two CpG motifs. The HBsAg and anti-HBs in serum from immunized mice were detected by ELISA and the number of IFN-secreting T cells was examined by ELISPOT. RESULTS: In BALB/c mice, the mice immunized with CpG ODN plus HBsAg showed higher specific humoral immune responses to HBsAg than those immunized with HBsAg alone. Compared with the immunization with HBsAg or CpG ODN alone, the immunization with HBsAg plus CpG ODN activated respectively 3 or 9 times more HBs-specific IFN-secreting T cells. In HBV transgenic mice, anti-HBs in serum were detected in the mice immunized with HBsAg and CpG ODN while no anti-HBs in serum in the mice immunized with HBsAg or CpG ODN alone. There was no significant difference in the level of HBsAg in serum between the three groups after vaccination (P>0.05) but the level declined in all three groups compared with those prevaccination (P<0.05). Compared with the immunization with HBsAg or CpG ODN alone, the immunization with HBsAg plus CpG ODN activated, respectively, 3 or 11 times more HBs-specific IFN-secreting T cells. CONCLUSION: CpG ODN can act as adjuvant to enhance the humoral and cell immune responses in BALB/c mice immunized with HBsAg. CpG ODN oligodeoxyribonucleotide combined with HBsAg can break the tolerance to this antigen in HBV transgenic mice and may become a potential prophylactic and therapeutic approach.