Trancriptional comparison of Zbtb32-deficient and -sufficient polyclonal resting memory B cells

Memory B cell responses are more rapid and of greater magnitude than are primary antibody responses. The mechanisms by which these secondary responses are eventually attenuated remain unknown. We demonstrate that the transcription factor ZBTB32 limits the rapidity and duration of antibody recall responses. ZBTB32 is highly expressed by mouse and human memory B cells, but not by their naive counterparts. Zbtb32-/- mice mount normal primary antibody responses to T-dependent antigens. However, Zbtb32-/- memory B cell-mediated recall responses occur more rapidly and persist longer than do control responses. Microarray analyses demonstrate that Zbtb32-/- secondary bone marrow plasma cells display elevated expression of genes that promote cell cycle progression and mitochondrial function relative to wild-type controls. BrdU labeling and adoptive transfer experiments confirm more rapid production and a cell-intrinsic survival advantage of Zbtb32-/- secondary plasma cells relative to wild-type counterparts. ZBTB32 is therefore a novel negative regulator of antibody recall responses. Wild type and Zbtb32-/- resting polyclonal splenic memory B cells were purified by fluorescence activated cell sorting, RNA was extracted, and used for Affymetrix microarray analysis. 5 biological replicates of wild type and Zbtb32-/- cells were included for each cell type.记忆B细胞应答相较于初次抗体应答，不仅启动更为迅速，应答强度也更高。此类继发应答最终被衰减的具体机制目前仍不明晰。本研究证实，转录因子ZBTB32（transcription factor ZBTB32）可抑制抗体回忆应答的速率与持续时长。ZBTB32在小鼠与人类的记忆B细胞中呈高表达，而在初始（naive）B细胞中无显著表达。Zbtb32-/-小鼠对T细胞依赖抗原可触发正常的初次抗体应答。然而，由Zbtb32-/-记忆B细胞介导的回忆应答，其启动速率更快且持续时长较对照组应答更长。基因芯片（microarray）分析结果显示，相较于野生型对照组，Zbtb32-/-继发骨髓浆细胞中，促进细胞周期进程与线粒体功能的基因表达水平显著升高。溴脱氧尿苷（BrdU）标记与过继转移实验证实，相较于野生型对应细胞，Zbtb32-/-继发浆细胞的生成速率更快，且具备细胞内在的生存优势。综上，ZBTB32是一类全新的抗体回忆应答负调控因子。本研究通过荧光激活细胞分选术（fluorescence activated cell sorting）纯化野生型与Zbtb32-/-静息多克隆脾脏记忆B细胞，提取RNA后用于Affymetrix基因芯片分析。每组细胞均设置5份生物学重复样本。