乙肝疫苗高免疫原性相关microRNA的研究

The duration of protection provided by hepatitis B vaccine remains unclear. It has been reported that the titre of anti-HBs induced by the vaccine determines the duration of protection. In many cases, when scientists studied the association of host factors with the response to the vaccine, they tended to focus on response or non-response, rather than the difference between those who maintain a high titre of anti-HBs for a long time and those whose anti-HBs became negative soon. MicroRNA has been reported to be involved in the immune response of hepatitis B vaccine and influence the titre of anti-HBs induced by the vaccine. Longan county, Guangxi was one of the first research areas to evaluate the effectiveness of hepatitis B vaccine in our country. It has the details of immunization. The proposed study will select subjects from Longan to establish a case-control study. All of the cases and controls responded with protective levels of anti-HBs when immunized 28 years ago. Cases will be those whose anti-HBs titres remained above 100 mIU/ml for 28 years after immunization. Controls will be those with anti-HBs titres below 10 mIU/ml but who remain negative for HBsAg. A microRNA microarray chip study will be performed to search for microRNAs that are strongly related to the response to the hepatitis B vaccine. The results will not only reveal the factors influencing the duration of high titre of anti-HBs, which may be helpful in improving current vaccines and their immune-protection and lead to life-long protection, but also will be helpful in resolving low and non-responses.

乙肝疫苗免疫保护期长短尚无定论。免疫产生抗体滴度高低影响免疫保护期长短。长期以来人们在探讨宿主因素与乙肝疫苗免疫应答关系时，主要集中在探索应答与不应答的原因，忽视常规免疫都产生保护性抗体的人群中，为何有些能长时间维持高抗体滴度、有些抗体很快阴转。据报道，microRNA参与乙肝疫苗免疫应答且影响疫苗诱导产生抗体滴度。广西隆安县是我国最早开展乙肝疫苗免疫效果观察的现场，有完整的免疫史记录。本项目将按病例对照研究原理，在隆安选择1987年出生、常规免疫都产生保护性抗体且目前抗体滴度仍≧100 mIU/ml者为病例，滴度﹤10mIU/ml但HBsAg仍为阴性者为对照，用microRNA芯片筛查方法，探索乙肝疫苗高免疫原性相关microRNA，研究结果不仅能阐明正常免疫应答人群高抗体滴度维持时间长、短原因，为提高现有疫苗免疫保护效果以达到终身免疫提供科学依据，而且有助于解决低免疫应答或不应答问题。

本研究旨在阐明乙肝疫苗免疫后高抗体组和低抗体组在microRNAs的差异，探索乙肝疫苗免疫原性相关microRNAs，阐明正常免疫应答人群高抗体滴度维持时间长、短的原因，从而为改善现有疫苗、提高其免疫保护效果以达到终身免疫提供科学依据。本研究按1:1匹配病例对照研究的原理，在广西隆安县选择65对病例和对照样本，选择1987-1993年出生、常规免疫都产生保护性抗体且目前抗体滴度仍≧100mIU/ml者为病例，滴度﹤10mIU/ml但HBsAg仍为阴性者为对照。初筛阶段通过高通量测序发现7条miRNAs在病例组和对照组血清中表达量差异显著，其中四条miRNAs通过qRT-PCR得到验证（hsa-miR-378a-3p、hsa-miR-378a-3p、hsa-miR-423-3p和 hsa-miR-7704）。4条miRNAs通过三个数据库共预测到1449个交集靶基因。GO和KEGG富集分析显示，miRNAs的靶基因主要与突触可塑性的调节、蛋白丝氨酸/苏氨酸激酶活性、化学突触传递的调节等相关，且主要富集于PI3K-Akt信号通路、Ras信号通路及MAPK信号通路，提示差异表达的miRNA可能通过多靶标、多途径影响乙肝疫苗免疫后产生保护性抗体并长时间维持高抗体滴度，其核心靶标和信号通路可能是PI3K-Akt信号通路和MAPK信号通路。