Ma Long, Wang Xiaomei, Bi Xiaoying, Yang Jiezuan, Shi Bin, He Xiaoyan, Ma Rui, Ma Qingqing, Yao Xinsheng
Department of Immunology, Research Center for Medicine & Biology, Innovation & Practice Base for Graduate Students Education, Zunyi Medical University, Zunyi, Guizhou, China.
The First Hospital of Hunan University of Chinese Medicine, Changsha, Hunan, China.
PLoS One. 2017 Jan 23;12(1):e0170479. doi: 10.1371/journal.pone.0170479. eCollection 2017.
Immunization with recombinant HBV vaccine induces specific immune responses in human causing B lymphocytes to produce protective HBsAb, and to form memory B lymphocytes, thereby facilitating HBV immunity in the body. However, B lymphocytes heterogeneity and characteristics are not fully elucidated. In this study, we conducted high-throughput sequencing of BCR heavy chain CDR3 repertoires in 3 healthy volunteers before and after the third immunization with recombinant HBV vaccine. We used Roche 454 Genome Sequencer FLX system to perform a comparative analysis of IgM and IgG H chain CDR3 repertoires. First, we found that the diversity of IgG H chain CDR3 repertoires was 1/6 of IgM on average. Moreover, after the third immunization with HBV vaccine, the diversity of IgG H chain CDR3 repertoires was 1/26 of IgM on average. Second, we detected relatively high levels of HBsAbs in all the healthy volunteers after immunization with HBV vaccine. The volunteers shared a small number of CDR3 sequences before and after immunization, and among each other. However, we did not find completely identical BCR H chain CDR3 amino acid sequences in these volunteers. Lastly, after immunization with recombinant HBV vaccine, the volunteers showed high frequency of IgG H chain CDR3 amino acid sequences mostly resulting from rearrangements of IGHV, IGHD and IGHJ, suggesting that the mechanism of high frequency CDR3 generation might be associated with the maturation of IgG affinity (somatic hypermutation) during the recombinant HBV vaccine-induced B lymphocyte responses. This study identified the characteristics and changes of BCR CDR3 repertoires before and after immunization with HBV vaccine, and evaluated the performance of the sequencing technology for this application. Our findings provide a basis for further research in B lymphocyte generated HBsAb heterogeneity and monitoring the maintenance of memory B lymphocytes.
重组乙肝疫苗免疫可在人体内诱导特异性免疫反应，使B淋巴细胞产生保护性乙肝表面抗体（HBsAb），并形成记忆B淋巴细胞，从而促进机体的乙肝免疫力。然而，B淋巴细胞的异质性和特性尚未完全阐明。在本研究中，我们对3名健康志愿者在重组乙肝疫苗第三次免疫前后的BCR重链CDR3库进行了高通量测序。我们使用罗氏454基因组测序仪FLX系统对IgM和IgG重链CDR3库进行了比较分析。首先，我们发现IgG重链CDR3库的多样性平均为IgM的1/6。此外，在乙肝疫苗第三次免疫后，IgG重链CDR3库的多样性平均为IgM的1/26。其次，我们在所有接种乙肝疫苗的健康志愿者中检测到相对较高水平的HBsAb。这些志愿者在免疫前后以及彼此之间共享少量的CDR3序列。然而，我们在这些志愿者中未发现完全相同的BCR重链CDR3氨基酸序列。最后，在接种重组乙肝疫苗后，志愿者显示出IgG重链CDR3氨基酸序列的高频出现，这些序列大多来自IGHV、IGHD和IGHJ的重排，表明高频CDR3产生的机制可能与重组乙肝疫苗诱导的B淋巴细胞反应过程中IgG亲和力的成熟（体细胞超突变）有关。本研究确定了乙肝疫苗免疫前后BCR CDR3库的特征和变化，并评估了该测序技术在此应用中的性能。我们的研究结果为进一步研究B淋巴细胞产生的HBsAb异质性以及监测记忆B淋巴细胞的维持提供了依据。
