GENETICS AND REGULATION OF THE IG VH REGION

了解抗体产生的机制 抗原和潜在病原体的多样性 长期以来一直是免疫学家的主要目标。 现在我们知道， 100个左右的VH基因理论上能够与几种免疫缺陷病毒中的每一种相关。 D和JH基因以产生H链多样性。 这种组合多样性 通过连接多样性，体细胞突变， 连接处（N节）的额外核苷酸和可能的基因 转换. 各种多样性产生机制的相对贡献 对免疫反应的了解很少，对储备的程度也是如此。 多样性潜力。 为了解决这些问题，一个独特的模型系统 将使用一组VH基因，其通常仅产生非常多的 对IG分子总排列的微小贡献将被迫 产生对生物体的免疫防御的全部VH贡献， 从而揭示了这些基因产生多样性的全部潜力。 允许（通过同种异型抑制）来自兔子的类扁桃体组织， 仅表达少数VH基因的人将被加工以产生Mu和γ VH cDNA文库形成H链mRNA。 生殖系DNA文库也将被 使用来自同一只兔子的非淋巴组织构建。 选择 克隆的cDNA将被测序，用于相互比较以及与它们的 祖先生殖系基因，以评估相对贡献和可能的 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。 生殖系基因的贡献和多样性产生机制 对潜在同种异型表达的影响也将进行研究。 潜 同种异型似乎是遗传上意想不到的VH区， 在一些兔子体内自发性低水平。 潜在的同种异型也可以是 迄今为止，通过注射 抗同种异型抗体 据推测，潜在的同种异型可能 在预先存在的同种异型/独特型调控网络中发挥作用。 来自潜伏性a1 IgG的VH区将首先在蛋白质位置处测序。 水平 这些信息将用于构建寡核苷酸探针 用于鉴定相应的cDNA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.