Development of the gene therapy model for allergic diseases

BCL6-KO小鼠未表现出生发中心形成和严重的过敏性炎症，伴有嗜酸性粒细胞浸润。我们发现BCL6在T细胞中的靶基因之一是IL-5基因。本项目通过建立控制BCL6表达的模型动物，研究BCL6在记忆性B细胞发育中的功能作用，并试图建立过敏性疾病的基因治疗模型。我们发现(1)BCL6-KO小鼠产生控制水平的IgG1二级抗体，并在脾脏中产生可转移的IgG1记忆B细胞。在这些记忆B细胞中，V-hedvy基因的突变为零。我们已经建立了携带igg - bcl6的转基因小鼠，转基因小鼠的生发中心形成和记忆反应增强。因此，Bcl6对生发中心的体细胞超突变和记忆B细胞的产生至关重要。(2)建立了携带lck-BCL6基因的转基因小鼠。当用抗cd3抗体刺激lck-BCL6小鼠脾T细胞时，IL-5的产生被特异性抑制。将lck-BCL6小鼠与BCL6-KO小鼠配对，BCL6-KO小鼠的过敏性炎症完全得到控制。建立了利用病毒载体进行基因转移的方法。我们希望在不久的将来开发出有效的基因治疗方法来治疗过敏性疾病。

BCL6-KO mice display no germinal center formation and severe allergic inflammation with eosinophilic infiltration. We found that one of the target gene of BCL6 in T cells is the IL-5 gene. In this project, we investigated the functional role of BCL6 in memory B cell development and tried to develop the gene therapy model for allergic diseases by establishing model animals in which expression of BCL6 is controlled. We show that (1) BCL6-KO mice produced control levels of secondary IgG1 antibodies, and generated transferable IgG1 memory B cells in the spleen. Mutation in the V-hedvy gene was nil in those memory B cells. We have established transgenic mice carrying the Ig-BCL6, and the germinal center formation and memory responses were augmented in transgenic mice. Therefore, Bcl6 is essential for somatic hypermutation and generation of memory B cells in germinal centers. (2) We have established transgenic mice carrying the lck-BCL6 gene. When splenic T cells from lck-BCL6 mice were stimulated with anti-CD3 antibody, IL-5 production was specifically suppressed. Those lck-BCL6 mice were mated with BCL6-KO mice and the allergic inflammation in BCL6-KO mice was completely controlled. We have established the gene transfer method using virus vectors. We wish to develop the efficient gene therapy method for allergic diseases near future.