Michael N, Accavitti M A, Masteller E, Thompson C B
Gwen Knapp Center for Lupus and Immunology Research, The University of Chicago, Chicago, IL 60637, USA.
Proc Natl Acad Sci U S A. 1998 Feb 3;95(3):1166-71. doi: 10.1073/pnas.95.3.1166.
In most vertebrates, a primary antibody repertoire is created through the recombination of a diverse set of Ig variable (V), diversity (D), and joining (J) gene segments. In contrast, an avian immune repertoire is generated by gene conversion of rearranged Ig genes during B cell development within the bursa of Fabricius, a lymphoid organ unique to birds. To investigate the properties of antigen-specific Igs created through the process of gene conversion, we have developed a system for the production of avian-derived mAbs. This system was used to produce multiple antibodies after a single immunization with a conserved peptide from the human cystic fibrosis transmembrane conductance regulator gene. Each antibody isolated was found to have arisen independently through a distinct series of gene conversion events. These primary antibodies displayed evidence of diversity in all of the complementarity determining regions of both heavy and light chains, and both the heavy and the light chains contributed to antigen specificity. In the light chains, diversity could be attributed to gene conversion events. The measured affinity constants of two of the antibodies were between 10(8) and 10(9) M-1, and the antibodies were functional in quantitative ELISA as well as immunohistochemical studies of cystic fibrosis transmembrane conductance regulator expression. These data demonstrate that antigen-specific antibodies produced by Ig gene conversion display both high affinity and specificity. In addition, the methods developed here provide the description of a system for the production of mAbs derived from a nonmammalian species.
在大多数脊椎动物中，主要抗体库是通过多种免疫球蛋白可变区（V）、多样性区（D）和连接区（J）基因片段的重排产生的。相比之下，禽类免疫库是由法氏囊（鸟类特有的淋巴器官）内B细胞发育过程中重排的免疫球蛋白基因的基因转换产生的。为了研究通过基因转换过程产生的抗原特异性免疫球蛋白的特性，我们开发了一种生产禽类来源单克隆抗体的系统。在用来自人囊性纤维化跨膜传导调节因子基因的保守肽进行单次免疫后，该系统用于产生多种抗体。发现分离出的每种抗体都是通过一系列不同的基因转换事件独立产生的。这些一级抗体在重链和轻链的所有互补决定区都显示出多样性证据，并且重链和轻链都对抗原特异性有贡献。在轻链中，多样性可归因于基因转换事件。其中两种抗体测得的亲和常数在10⁸至10⁹ M⁻¹之间，并且这些抗体在定量ELISA以及囊性纤维化跨膜传导调节因子表达的免疫组织化学研究中具有功能。这些数据表明，由免疫球蛋白基因转换产生的抗原特异性抗体具有高亲和力和特异性。此外，这里开发的方法提供了一种生产源自非哺乳动物物种的单克隆抗体系统的描述。
