GENETICS AND REGULATION OF THE IG VH REGION

对抗体产生机制的理解 对各种各样的抗原和潜在病原体的多样性 长期以来，这一直是免疫学家的主要目标。现在已经知道，每一个 从理论上讲，大约100个VH基因能够与几个 D和JH基因产生H链多样性。这种组合多样性 通过连接多样性，体细胞突变，插入 连接处的额外核苷酸(N个片段)和可能的基因 转换。 不同的多样性产生机制对 人们对免疫反应知之甚少，储备的程度也是如此。 多样性潜力。为了解决这些问题，一个独特的模式系统 将在其中使用一组VH基因，这组基因通常只使非常 对总免疫球蛋白分子阵列的微小贡献将被迫 产生整个VH对生物体免疫防御的贡献， 从而揭示了这些基因产生多样性的全部潜力。 兔的淋巴组织允许(通过同种异型抑制) 只表达几个VH基因将被处理以产生Mu和Gamma VH C DNA文库形成H链m RNA。一个生殖系DNA文库也将 用同一只兔子的非淋巴组织构建的。已选择 克隆的cDNA将被测序，以便相互比较和与它们的 评估祖细胞生殖系基因的相对贡献和可能 体细胞突变、基因转换、D和JH的相互关系 与VH的关联，或其他多样性产生机制。 种系基因的贡献及其多样性产生机制 对潜伏的同种异型的表达也将进行调查。潜伏期 同种异型似乎是遗传上意想不到的VH区域 在一些兔子身上自发地处于低水平。潜在的同种异型也可以是 在迄今测试的所有兔体内均可通过注射 抗同种异型抗体。据推测，潜在的同种异型可能 在先前存在的同种异型/独特型调控网络中发挥作用。 来自潜伏期免疫球蛋白的VH区将首先在蛋白质处进行测序 水平。这些信息将被用于构建寡核苷酸探针 用于鉴定相应的cDNAs和生殖系基因。

An understanding of the mechanisms involved in the generation of antibody diversity to the tremendous variety of antigens and potential pathogens has long been a major goal of immunologists. It is now known that each of the l00 or so VH genes are theoretically able to associate with each of several D and JH genes to generate H-chain diversity. This combinatorial diversity is augmented by junctional diversity, somatic mutation, the insertion of additional nucleotides at junctions (N segments) and possibly gene conversion. The relative contribution of the various diversity generating mechanisms to an immune response is poorly understood, as is the extent of the reserve diversity potential. To address these questions, a unique model system will be used in which a set of VH genes which ordinarily makes only a very minor contribution to the total array of Ig molecules will be forced to generate the entire VH contribution to the immune defense of the organism, thus revealing the full diversity-generating potential of these genes. Lymphoid tissue from a rabbit permitted (through allotype suppression) to express only a few VH genes will be processed to yield both Mu and Gamma VH cDNA libraries form H-chain mRNA. A germline DNA library will also be constructed using nonlymphoid tissues from the same rabbit. Selected cloned cDNAs will be sequenced for comparison to each other and to their progenitor germline genes to assess the relative contributions and possible interrelationships of somatic mutation, gene conversion, D and JH associations with VH, or other diversity-generating mechanisms to diversity. The contribution of germline genes and the diversity-generating mechanisms to the expressin of latent allotypes will also be investigated. Latent allotypes appear to be genetically unexpected VH regions which occur spontaneously at low levels in some rabbits. Latent allotypes can also be reliably induced in all rabbits thus far tested through the injection of anti-allotype antibody. It has been postulated that latent allotypes may play a role in a pre-existing allotype/idiotype regulatory network. The VH region from latent al IgG will be first sequenced at the protein level. This information will be used to construct oligonucleotide probes to be used to identify the corresponding cDNA and germline genes.