An asymmetric antibody repertoire is shaped between plasmablasts and plasma cells after secondary immunization with (4-hydroxy-3-nitrophenyl)acetyl chicken γ-globulin.
An asymmetric antibody repertoire is shaped between plasmablasts and plasma cells after secondary immunization with (4-hydroxy-3-nitrophenyl)acetyl chicken γ-globulin.
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用(4-羟基-3-硝基苯基)乙酰基鸡γ-球蛋白二次免疫后，在浆母细胞和浆细胞之间形成不对称抗体库。
DOI：
10.1093/intimm/dxv040
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发表时间：
2015
期刊：
影响因子：
4.4
通讯作者：
Azuma T
中科院分区：
文献类型：
--
作者：
Tashiro Y;Murakami A;Goizuka R;Shimizu T;Kishimoto H;Azuma T
抗体亲和力成熟的结构基础研究是通过测量分泌抗体的亲和力来进行的，结构信息通常从记忆B细胞的BCR的核苷酸序列中获得。我们认为，重要的是要确定免疫后同一时间点浆细胞分泌的抗体是否真的与记忆B细胞上的BCR一致。我们用生物素-抗CD138和链霉亲和素-NP-别藻蓝蛋白亲和基质技术分离了分泌抗(4-羟基-3-硝基苯基)乙酰基(NP)半抗原抗体的浆细胞，自体浆细胞分泌的抗NP抗体优先与之结合。我们发现，在初级反应中，浆母细胞占据了抗体分泌细胞室的90%，它们分泌的抗体的VH区由V186.2+Tyr95+序列编码，这通过第33位重链的体细胞超突变(SHM)提高了中等亲和力水平。二次免疫后，抗体亲和力进一步提高，这是由于出现了大量分泌V186.2+Gly95+抗体的浆细胞和分泌V186.2+Tyr95+抗体的浆母细胞，这些细胞通过多个SHM获得高亲和力。然而，我们没有检测到任何分泌V186.2+Gly95+抗体的成浆细胞，这表明成浆细胞和浆细胞具有不同的抗体库，即它们各自的抗体库是不对称的。在这些发现的基础上，我们讨论了记忆B细胞的BCR亲和力与浆母细胞和浆细胞的关系及其与个体发育的关系。
Studies on the structural basis of antibody affinity maturation have been carried out by measuring the affinity of secreted antibodies, and information on structures has often been obtained from nucleotide sequences of BCRs of memory B cells. We considered it important to establish whether the repertoire of secreted antibodies from plasma cells is really in accord with that of BCRs on memory B cells at the same time points post-immunization. We isolated plasma cells secreting antibodies specific to (4-hydroxy-3-nitrophenyl)acetyl (NP) hapten by affinity matrix technology using biotin–anti-CD138 and streptavidin–NP–allophycocyanin, to which anti-NP antibodies secreted by autologous plasma cells bound preferentially. We found that plasmablasts occupied >90% of the antibody-secreting cell compartment in the primary response and that they secreted antibodies whose VHregions were encoded by V186.2+Tyr95+sequences, which provided an increase in the medium level of affinity by somatic hypermutation (SHM) of heavy chains at position 33. After secondary immunization, a further increase in antibody affinity was observed, which was explained by the appearance of a number of plasma cells secreting V186.2+Gly95+antibodies that acquired high affinity by multiple SHMs as well as plasmablasts secreting V186.2+Tyr95+antibodies. However, we did not detect any plasmablasts secreting V186.2+Gly95+antibodies, showing that plasmablasts and plasma cells have a different antibody repertoire, i.e. their respective repertoires are asymmetric. On the basis of these findings, we discussed the relationship between the BCR affinity of memory B cells and plasmablasts as well as plasma cells as pertaining to their ontogeny.