质粒剂量和免疫次数对基因枪免疫DNA疫苗免疫反应的影响

目的研究质粒剂量和免疫次数对基因枪免疫DNA疫苗免疫反应的影响。方法构建携带HIV-1 Env gp145基因的DNA疫苗质粒p1.0-Env,分别采用肌肉注射和基因枪方法免疫BALB/c小鼠。其中,基因枪免疫采用不同剂量或不同次数。ELISA法检测小鼠体内Env特异性抗体水平。结果基因枪免疫小鼠诱导的抗体水平显著高于肌肉注射免疫。在0.1～2.25μg剂量范围内,基因枪免疫小鼠体内的Env特异性抗体水平随疫苗剂量的增加不断提高。加大免疫剂量至5μg和10μg,不能提高体液免疫反应水平。基因枪免疫1次和2次所诱导的特异性抗体水平很弱,免疫3次可诱导高水平的抗体应答。结论基因枪免疫能有效提高DNA疫苗所诱导的抗体应答,小鼠的最适免疫剂量约为2.25μg,2.25μg免疫3次可诱导较强的体液免疫反应。

Effect of Plasmid Dosage and Immunization Occasions on Immune Response Induced by Gene-gun Delivered DNA Vaccine

Objective To investigate the effect of plasmid dosage and immunization occasions on the immune response induced by gene-gun delivered DNA vaccine.Methods DNA vaccine plasmid p1.0-Env carrying the Env gp145 gene of HIV-1 was constructed.BALB/c mice were inoculated with the constructed plasmid at various dosages by gene-gun for various times,using those inoculated by i.m.injection as control.The specific antibody level against Env of immunized mice was determined by ELISA.Results The antibody level induced with the DNA vaccine delivered by gene-gun was significantly higher than that by i.m.injection.At a dosage range of 0.1～2.25 μg,the specific antibody level against Env induced by gene-gun increased with the increasing dosage of DNA vaccine.However,no further enhancement of humoral immune response was observed after the dosage of DNA vaccine increased to 5 or 10 μg.The delivery of DNA vaccine by gene-gun for 1 and 2 times induced only low specific antibody responses,while that for 3 times induced high antibody response.Conclusion Delivery by gene-gun enhanced the antibody response induced with DNA vaccine.The optimal dosage of DNA vaccine for mice was about 2.25 μg.The immunization with 2.25 μg of DNA vaccine by gene-gun for 3 times induced high humoral immune response.