摘要目的 评价环二核苷酸(cyclic guanosine monophosphate-adenosine monophosphate, cGAMP)在诺如病毒(GⅡ.4) 病毒样颗粒(virus like particles,VLPs)疫苗研发中作为佐剂的免疫增强效应.方法 将cGAMP和铝盐佐剂(氢氧化铝)分别与不同剂量诺如病毒(GⅡ.4)VLPs抗原配伍,经肌肉注射免疫BALB/c小鼠,通过测定免疫血清中抗VLPs特异性IgG抗体及其亚型,检测阳性血清中模拟中和抗体水平,比较两种佐剂对VLPs抗原免疫效果的促进作用.结果 以cGAMP为佐剂,VLPs可诱导较高的血清特异性IgG抗体应答;用相同剂量VLPs抗原免疫,配伍cGAMP佐剂诱导的IgG抗体应答水平明显高于铝佐剂,cGAMP配伍低剂量VLPs加强免疫后诱导的IgG抗体水平与铝佐剂配伍高剂量VLPs相当,模拟中和抗体水平与血清IgG水平相对应.结论 cGAMP可显著增强针对诺如病毒(GⅡ.4)VLPs的特异性体液免疫应答,其佐剂活性高于传统铝佐剂,是一种有望应用于疫苗研发的新型佐剂.

abstractsObjective To evaluate the immunopotentiating effect of cyclic guanosine monophos-phate-adenosine monophosphate (cGAMP) as an adjuvant on norovirus (GⅡ. 4) virus like particles (VLPs) in the development of norovirus vaccine. Methods BALB/c mice were intramuscularly immunized with norovirus (GⅡ.4) VLPs composed of capsid protein VP1 in combination with cGAMP or Al(OH)3. Norovirus VLPs-specific antibodies in serum were detected by ELISA. A synthetic histo-blood group antigen (HBGA)-VLPs blocking assay was used to analyze neutralizing antibodies against norovirus VLPs in serum samples. Results Immunization with norovirus VLPs in the presence of cGAMP induced a strong humoral immune response in BALB/c mice. Levels of specific IgG antibodies in serum induced by using cGAMP as the adjuvant were significantly higher than those induced by using Al(OH)3adjuvant when immunization of BALB/c mice with the same dosage of VLPs. The antibody level induced by 1 μg of VLPs in combination with cGAMP was equivalent to that elicited by 10 μg of VLPs combined with Al(OH)3adjuvant. Results of the synthetic HBGA-VLPs blocking assay showed that the blocking rate in cGAMP+VLPs immunization group were significantly higher than that in Al(OH)3+VLPs immunization group when using the same dosage of VLPs. No significant difference in blocking rate was observed between cGAMP+VLPs(1 μg) and Al(OH)3+VLPs (10 μg) immunization groups. Conclusion cGAMP significantly enhanced the specific humoral immune response induced by norovirus (GⅡ.4) VLPs in mice as compared with Al(OH)3adjuvant. It might be used as a novel adjuvant to replace the traditional aluminum adjuvant in the development of norovir-us vaccine.