Naïve B cells vs germina center B cells

Activation-induced cytidine deaminase (AID) is essential for the generation of antibody memory but also targets oncogenes among others. We investigated the transcriptional regulation of the AID gene, Aicda, in the class switch–inducible CH12F3-2 cells, and found that the Aicda regulation involves derepression by several layers of positive regulatory elements in addition to the 5’ promoter region. The 5’ upstream region contains functional motifs for the response to signaling by cytokines, CD40-ligand, or stimuli that activate NF-κB. The first intron contains functional binding elements for the ubiquitous silencers c-Myb and E2f and for B cell–specific activator Pax5 and E-box-binding proteins. To confirm involvement of these transcription factors in Acida regulation, we examined their expression profile of these factors in naïve and germinal center B cells. Naïve B cells were defined as B220+PNA-Fas- and germinal center B cells were defined as B220+PNA+Fas+ cells. These cells were purified from immunized mouse lymph nodes or mouse Peyer's patches by using FACS Aria. Samples are as follows: pLN GC, pLN naïve, PP GC, PP naïve, (each 1 sample, prepared from pooled 3-5 mice)