METHODS: In this study, formalin-inactivated EV-A71 and EV-D68 were used as antigens, while PS-G, a polysaccharide from Ganoderma lucidum, was used as an adjuvant. Natural polysaccharides have the characteristics of intrinsic immunomodulation, biocompatibility, low toxicity, and safety. Mice were immunized intranasally with PBS, EV-A71, EV-D68, or EV-A71 + EV-D68, with or without PS-G as an adjuvant.
RESULTS: The EV-A71 + EV-D68 bivalent vaccine generated considerable EV-A71- and EV-D68-specific IgG and IgA titres in the sera, nasal washes, saliva, bronchoalveolar lavage fluid, and feces. These antibodies neutralized EV-D68 and EV-A71 infectivity. They also cross-neutralized infections by different EV-D68 and EV-A71 sub-genotypes. Furthermore, compared with the PBS group, EV-A71 + EV-D68 + PS-G-vaccinated mice exhibited an increased number of EV-D68- and EV-A71-specific IgA- and IgG-producing cells. In addition, T-cell proliferative responses, and IFN-γ and IL-17 secretion in the spleen were substantially induced when PS-G was used as an adjuvant with EV-A71 + EV-D68. Finally, in vivo challenge experiments demonstrated that the immune sera induced by EV-A71 + EV-D68 + PS-G conferred protection in neonate mice against lethal EV-A71 and EV-D68 challenges as indicated by the increased survival rate and decreased clinical score and viral RNA tissue expression. Taken together, all EV-A71/EV-D68 + PS-G-immunized mice developed potent specific humoral, mucosal, and cellular immune responses to EV-D68 and EV-A71 and were protected against them.
CONCLUSIONS: These findings demonstrated that PS-G can be used as a potential adjuvant for EV-A71 and EV-D68 bivalent mucosal vaccines. Our results provide useful information for the further preclinical and clinical development of a mucosal bivalent enterovirus vaccine against both EV-A71 and EV-D68 infections.
方法:在本研究中,福尔马林灭活的EV-A71和EV-D68用作抗原,而PS-G,一种来自灵芝的多糖,用作佐剂。天然多糖具有内在免疫调节的特点,生物相容性,低毒性,和安全。用PBS对小鼠进行鼻内免疫,EV-A71、EV-D68或EV-A71+EV-D68,有或没有PS-G作为佐剂。
结果:EV-A71+EV-D68二价疫苗在血清中产生了相当大的EV-A71和EV-D68特异性IgG和IgA滴度,洗鼻剂,唾液,支气管肺泡灌洗液,还有粪便.这些抗体中和EV-D68和EV-A71感染性。它们还通过不同的EV-D68和EV-A71亚基因型交叉中和感染。此外,与PBS组相比,EV-A71+EV-D68+PS-G接种的小鼠表现出增加数量的EV-D68-和EV-A71特异性IgA-和IgG-产生细胞。此外,T细胞增殖反应,当PS-G用作EV-A71+EV-D68的佐剂时,脾脏中的IFN-γ和IL-17分泌基本上被诱导。最后,体内激发实验表明,由EV-A71+EV-D68+PS-G诱导的免疫血清赋予新生小鼠针对致死性EV-A71和EV-D68激发的保护作用,如通过增加的存活率和降低的临床评分和病毒RNA组织表达所指示。一起来看,所有EV-A71/EV-D68+PS-G免疫小鼠均产生了强效的特异性体液,粘膜,和对EV-D68和EV-A71的细胞免疫反应,并受到保护。
结论:这些发现表明,PS-G可用作EV-A71和EV-D68二价粘膜疫苗的潜在佐剂。我们的结果为针对EV-A71和EV-D68感染的粘膜二价肠道病毒疫苗的进一步临床前和临床开发提供了有用的信息。