The marginal zone (MZ) is largely composed of a unique subpopulation of B cells, the so-called MZ-B cells. At a molecular level, memory B cells are characterized by the presence of somatically mutated IGV genes. The earliest studies in the rat have documented the presence of hapten-specific MZ-B cells after immunization in the MZ. This work later received experimental support demonstrating that the IGHV-Cµ transcripts expressed by phenotypically defined splenic MZ-B cells (defined as CD90negIgMhighIgDlow B cells) can carry somatic hypermutation. However, only a minor fraction (< 10%-20%) of these MZ-B cells is mutated and is considered to represent memory B cells. Memory B cells can either be class-switched (IgG, IgA, IgE), or non-class-switched (IgM) B cells. B cells in the MZ are a heterogeneous population of cells and both naïve MZ-B cells; class switched and unswitched memory MZ-B cells are present at this unique site in the spleen. Naïve MZ-B cells carry unmutated Ig genes, produce low-affinity IgM molecules and constitute a first line of defense against invading pathogens. Memory MZ-B cells express high-affinity Ig molecules, directed to (microbial) antigens that have been encountered. In this review, we report on the memory compartment of splenic MZ-B cells in the rat to provide insights into the origin and function of these memory MZ-B cells.

中文翻译：

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记忆边缘区B细胞的异质性。

边缘区（MZ）主要由B细胞的独特亚群组成，即所谓的MZ-B细胞。在分子水平上，记忆B细胞的特征是存在体细胞突变的IGV基因。在大鼠中的最早研究已证明在MZ中免疫后存在半抗原特异性MZ-B细胞。这项工作后来得到实验支持，表明表型定义的脾MZ-B细胞（定义为CD90negIgMhighIgDlow B细胞）表达的IGHV-Cµ转录本可以携带体细胞超突变。但是，这些MZ-B细胞中只有一小部分（<10％-20％）被突变，被认为代表记忆B细胞。记忆B细胞可以是类别转换（IgG，IgA，IgE）或非类别转换（IgM）B细胞。MZ中的B细胞是异质性细胞群体，都是纯MZ-B细胞。脾的这个独特部位存在MZ-B类交换和未交换存储器。幼稚的MZ-B细胞携带未突变的Ig基因，产生低亲和力的IgM分子，并构成了抵御入侵病原体的第一道防线。记忆MZ-B细胞表达针对已遇到的（微生物）抗原的高亲和力Ig分子。在这篇综述中，我们报告了大鼠脾脏MZ-B细胞的记忆区室，以提供对这些记忆MZ-B细胞的起源和功能的见解。直接针对已经遇到的（微生物）抗原。在这篇综述中，我们报告了大鼠脾脏MZ-B细胞的记忆区室，以提供对这些记忆MZ-B细胞的起源和功能的见解。直接针对已经遇到的（微生物）抗原。在这篇综述中，我们报告了大鼠脾脏MZ-B细胞的记忆区室，以提供对这些记忆MZ-B细胞的起源和功能的见解。