T cell dependent immune responses: B cell activation and differentiation Group1 Fo, Group2 GC1, Group3 GC2

Upon immunization with a T cell dependent antigen naive follicular B cells (Fo) are activated and a germinal center reaction is induced. Within the next 2 weeks large germinal centers develop where the process of affinity maturation takes place. To analyze the gene expression profile of resting and activated B cells, follicular B cells (Fo), B cells from early (GC1) and late germinal centers (GC2) were isolated and their gene expression profile compared. Gene expression profiles of Fo versus GC1 and GC2 B cells, respectively. Naïve Fo B cells were isolated from non-immunized BALB/c mice. Germinal center B cells sorted from spleen cell suspensions of BALB/-c mice immunized with the T cell dependent antigen 2-phenyl Oxazolone. GC1 B cells were isolated 7 days after primary immunization. GC2 cells were isolated 15 days after primary immunization. After total RNA extraction, reverse transcription, cDNA extraction, the biotinylated cRNA was transcribed, fragmented, and 15 µg cRNA hybridized in duplicates for each of the three groups to the GeneChip arrays. Group1: Fo, Group2: GC1, Group3: GC2. Lists of differentially regulated genes were created using High Performance Chip Data Analysis (HPCDA) with Bioretis database (http://www.bioretis-analysis.de). Worldwide data sharing is possible via Bioretis, please ask the authors.

当以T细胞依赖性抗原（T cell dependent antigen）免疫小鼠时，初始滤泡B细胞（Fo）会被激活并诱导生发中心（germinal center）反应。在随后的两周内，会形成大型生发中心，亲和力成熟过程即在其中发生。为分析静息态与活化态B细胞的基因表达谱，研究人员分离得到滤泡B细胞（Fo）、早期生发中心B细胞（GC1）与晚期生发中心B细胞（GC2），并分别比较Fo与GC1、Fo与GC2的基因表达谱。初始Fo B细胞分离自未免疫的BALB/c小鼠；生发中心B细胞则分离自经T细胞依赖性抗原2-苯基恶唑酮（2-phenyl Oxazolone）免疫的BALB/c小鼠脾细胞悬液。其中GC1 B细胞于初次免疫后7天分离获取，GC2细胞则于初次免疫后15天分离。完成总RNA提取、逆转录、cDNA提取后，研究人员转录得到生物素标记的cRNA并对其进行片段化；将3组样品（Group1：Fo、Group2：GC1、Group3：GC2）各15 μg的cRNA分别重复两次与基因芯片（GeneChip arrays）进行杂交。研究使用搭载Bioretis数据库（http://www.bioretis-analysis.de）的高性能芯片数据分析（High Performance Chip Data Analysis, HPCDA）工具，筛选得到差异表达基因列表。该研究数据可通过Bioretis平台实现全球共享，具体事宜可联系本文作者。