B cell activating factor (BAFF) induces the transcription of recombination-activating genes in transitional stage 1 B cells

Abstract

A high level of receptor editing appeared to favor the loss of tolerance on an autoimmune background. However, the factors inducing imbalance of the receptor editing gene is still not clear. First, we used myelin oligodendrocyte glycoprotein (MOG) to induce experimental allergic encephalitis (EAE) in C57BL/6 mice. We found that recombination-activating genes (RAG) are expressed in periphery transitional stage 1 B (T1B) cells from EAE mice. In addition, RAG1 and RAG2 expression was up-regulated in T1B cells from the EAE model. At the same time, we also detected a level of the RAG gene in MS patients. The results were in accordance with those in the EAE mice model. Furthermore, we found that RAG1 and RAG2 increase was associated with BAFF. In vitro culture assay shows that BAFF upregulated RAG1 and RAG2 mRNA expression in T1B cells from wild type mice. Block of BAFF with TACI-IgG reduced RAG1 and RAG2 expression in T1B cells from EAE mice. The study suggests that BAFF up-regulated the RAG expression to induce receptor editing in autoimmune diseases.