基因枪法和肌内注射法免疫HCV NS3/4A诱导小鼠免疫应答的比较

目的比较肌内注射法和基因枪法对免疫效果的影响。方法将携带HCV NS3/4A基因的质粒pcDNA3.1-NS3/4A,分别肌内注射和基因枪免疫BALB/c小鼠。基因枪免疫采用2μg/只和10μg/只两种剂量,肌内注射免疫的剂量为100μg/只,共免疫3次。分别于第3次免疫后10 d和20 d,收集小鼠血清、分离脾细胞;ELISA法检测小鼠血清中特异性抗体水平;ELIspot检测小鼠IFN-γI、L-2和IL-4;非放射性细胞毒性试验检测其对肿瘤细胞的杀伤作用,从而比较肌内注射和基因枪法激发小鼠产生体液免疫和细胞免疫应答的影响。结果免疫后第10 d检测结果表明,2μg/只和10μg/只基因枪法免疫产生的抗体效价分别为1∶500和1∶1 000,100μg/只肌内注射免疫产生的抗体效价为1∶1 000。第20 d再次检测,基因枪法产生的抗体效价仍为1∶500和1∶1 000,肌内注射降低为1∶500。2μg/只和10μg/只基因枪免疫产生的IFN-γ和IL-2均高于100μg/只肌内注射免疫。但这两种免疫方法均未激发IL-4的水平。在不同的效靶比情况下,10μg/只和2μg/只基因枪免疫激发的CTL细胞杀伤活性均高于100μg/只肌内注射免疫。结论基因枪法免疫小鼠诱导的体液免疫和细胞免疫应答均显著高于肌内注射免疫。

Comparative studies on immune responses of BALB/c mice immuned with HCV NS3/4A by routes of gene gun bombardment and intramuscular injection

Objective A DNA vaccine expressing HCV NS3/4A was evaluated for inducing immunity in mice. The plas-mid was administered via intramuscular injection （ IM ） and gene gun bombardment （ GB ）. Methods Immunizing the BALB/C mice separately with 2 μg and 10 μg pcDNA3.1-NS3/4A by GB comparing to100 μg by IM for three times at 2 weeks intervals. Collecting the sera of mice and separating the splenocytes separately at 10 d and 20 d after immunization. The antibodies in the sera were assayed with ELISA. IFN-γ,, IL-2, IL-4 was detected by ELlspot and CTL assays were per-formed with the non-radioactive cytotoxicity assay kit. Results The result from ELISA at 10 d after immunization showed that the specific antibody titers with 2 μg and 10 μg by GB were 1 ： 500 and 1 ： 1 000 compared to 1 ： 1 000 by IM. Sur-prisingly the specific antibody titers by GB were still 1 ： 500 and 1 ： 1 0013 detected at 20 d, but it decreased to 1 ： 500 by IM. The result from ELIspot showed that IFN-γ and IL-2 by GB were higher than that by IM （ P〈0.05 }. IL-4 was not detec- ted remarkedly during all groups. The special cytotoxic effects of immunization with 10 μg and 2μg by GB were stronger than 100 μg by IM. Conclusion Overall, our results suggest that the celuller and humoral immune response against HCV NS3/4A vaccinated by GB were higher than that by IM.