RABBIT ALLOTYPES--STRUCTURE, ORGANIZATION AND REGULATED EXPRESSION OF IG GENES

本研究利用分子生物学技术对兔免疫系统基因进行了研究， 生物学和免疫学。 我们生产了抗RAG-2抗体， 发育中的兔胸腺和阑尾组织。 我们利用表面 标记物CD 43和IgM来区分两个阑尾细胞群， 表达RAG-1转录物的6至9周龄兔。 我们推测 在B细胞成熟的不同阶段， 可能与阑尾作为B细胞和淋巴细胞的部位的功能有关。 发展和多样化。 IgM相关B细胞受体 在兔B细胞上发现分子为异聚体结构， 非还原分子量约为75 kDa和135 kDa， 37和42 kDa亚基。 单克隆抗体的免疫学研究 抗体表明，这些蛋白质是兔的同源物， 鼠Ig-β（B29）和Ig-α（mb-1）。 我们研究了RAD 51， 因为我们假设RAD 51可以在兔阑尾中发挥作用， 发生在幼兔阑尾的基因转换事件， 它们的抗体库 RT-PCR扩增出了 兔RAD 51的编码序列，发现兔、人和 小鼠RAD 51高度相似。 我们开发了一种逆转录PCR 模拟试验，并测量了RAD 51转录本的相对丰度， 在不同组织中，在FACS分选的B和T细胞以及B细胞亚群中。 我们 在睾丸、胸腺和睾丸中发现了相对高水平的RAD 51信息， 阑尾可能与高有丝分裂和/或减数分裂活动相关。 在北方印迹上发现的三种不同大小的条带可以反映 不同的转录起始位点，选择性剪接或 不同的聚（A）加成位点。 在人和小鼠中， DQ 52基因在B细胞发育早期优先重排。 为了测试这种基于DH基因片段重排的偏好是否 在3'端存在邻近性，我们克隆了兔 DQ 52基因。 编码区序列与小鼠DQ 52相同，但 3 ′重组信号序列具有非典型九聚体。 DQ52 基因的使用频率非常低，如果有的话。 我们只找到一个VDJ 来自28天胎肝B细胞的具有8bp的序列，其匹配 种系DQ 52序列。 而不是重新排列DQ 52，另一个DH基因， 位于JH上游约32 kb处的Df是优选的靶标。 因此，与人和小鼠相反，兔优先表达DH 该基因在B细胞个体发育早期位于DH区的中间。 这可能与VH到DH的更频繁的初始重排相关 在兔B细胞中。

We studied genes of the rabbit immune system by techniques of molecular biology and immunology. We produced anti-RAG-2 antibodies and studied developing rabbit thymus and appendix tissues. We used the surface markers CD43 and IgM to distinguish two appendix cell populations from 6 to 9-week-old rabbits that expressed RAG-1 transcripts. We speculate that the appearance of CD43 during different stages of B-cell maturation may be related to the function of the appendix as a site of both B-cell development and diversification. IgM associated B cell receptor molecules were found on rabbit B cells as heteromeric structures with nonreduced molecular weights of approximately 75 kDa and 135 kDa composed of 37 and 42 kDa subunits. Immunological studies with monoclonal antibodies suggested that these proteins are the rabbit homologues of murine Ig-beta (B29) and Ig-alpha (mb-1). We investigated RAD51 in rabbit appendix because we postulated that RAD51 could play a role in the gene conversion events that occur in young rabbit appendix to diversify their antibody repertoire. We cloned and sequenced RT-PCR amplified rabbit RAD51 and found that the coding sequences of rabbit, human and mouse RAD51 are highly similar. We developed a reverse transcriptase PCR mimic assay and measured the relative abundance of RAD51 transcripts in different tissues, in FACS-sorted B and T cells and B-cell subsets. We found relatively high levels of RAD51 message in testis, thymus and appendix that may correlate with high mitotic and/or meiotic activities. Bands of three different sizes found on Northern blots could reflect distinct transcription initiation sites, alternative splicing or different poly (A) addition sites. In man and mouse, the 3'-most DH gene, DQ52, is preferentially rearranged early in B-cell development. To test whether this preference for rearranging a DH gene segment based on 3' end proximity exists in rabbit, we cloned and sequenced the rabbit DQ52 gene. The coding region sequence is identical to a mouse DQ52 but the 3' recombination signal sequence has an atypical nonamer. The DQ52 gene was utilized very infrequently, if at all. We found only one VDJ sequence from 28 day fetal liver B-cells with 8 bp that matched the germline DQ52 sequence. Instead of rearranging DQ52, another DH gene, Df, localized about 32 kb upstream of the JH was the preferred target. Thus, in contrast to man and mouse, rabbits preferentially express a DH gene located in the middle of the DH region early in B cell ontogeny. This may correlate with more frequent initial rearrangement of VH to DH in rabbit B cells.