2018 Fiscal Year Final Research Report

Investigation of the initial immune-responsiveness and memory immunity to the hepatitis B vaccine

Research Project

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Project/Area Number	15K08746
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Epidemiology and preventive medicine
Research Institution	Iwate Medical University
Principal Investigator	Miyasaka Akio 岩手医科大学, 医学部, 准教授 (80382597)
Research Collaborator	Takikawa Yasuhiro Wang Tang Yoshida Yuichi
Project Period (FY)	2015-04-01 – 2019-03-31
Keywords	HBワクチン / TCR β レパトア / BCR IgG H chain レパトア
Outline of Final Research Achievements	To clarify an immune response for the hepatitis B (HB) vaccine, we conducted high-throughput sequencing of the T cell receptor (TCR) beta chain and B cell receptor (BCR) IgG heavy (H) chain complementary determining region 3 (CDR3) repertoires in 5 volunteers before and after the immunizations with the HB vaccine. The all 5 participants acquired HBs antibody. The TCR beta chain CDR3 repertoire diversity significantly increased, while the BCR IgG H chain CDR3 repertoire diversity significantly decreased after the second vaccination. These diversity changes might be associated with a better response to the HB vaccine. It is possible that the TCR beta chain and BCR IgG H chain CDR3 repertoires may have changed within the same numbers of unique reads. Our data failed to identify the specific dominant clones that responded to the HB vaccine. As for our investigation of the memory immunity, the HB-vaccinated subjects had very low numbers of memory B cells in their peripheral blood.
Free Research Field	肝臓
Academic Significance and Societal Importance of the Research Achievements	HBワクチンに対する初期免疫応答について解析を行ない、HBs抗体獲得者において2回接種後のTCRβ chainレパトア、BCR IgG H chainレパトアの変化はHBs抗体獲得のサロゲートマーカーとなる可能性が示唆された。今後、さらに解析をすすめることにより不応例への対策やワクチン回数を減らすための方策などに役立つと考えられた。また、HBワクチン接種歴ある者ではmemory B細胞は末梢血中に僅かに存在している可能性があった。HBワクチンのユニバーサルワクチネーションが施行されるようになりHBs抗体獲得後の免疫記憶の有効性を明らかにすることは追加接種を減らすなどの有用性があると考えられた。