TRANSGENIC ANIMAL MODELS USING YACS

Genpharm计划的目标是开发引入 将酵母人工染色体(YAC)导入小鼠的生殖系，并 将该技术应用于转基因小鼠的制备 一个广泛的，完全的人类免疫球蛋白曲目。这些老鼠会允许 以类似于以下方法分离人的单抗 啮齿动物的单抗。 在第一阶段，开发了将YAC引入小鼠的方法， 和携带编码最低能力人类的小YAC的小鼠 免疫球蛋白转基因表达人重链IgM 血清中的抗体。在第二阶段，第一阶段产生的动物 将对转基因功能和表达进行充分的表征。 额外的恒定区和可变区将在YAC中克隆并添加 到第一阶段YAC，以允许类别转换、体细胞突变和 Ig生产。这些第二阶段的转基因将被引入小鼠体内 使用在第一阶段开发的方法学，转基因小鼠也将 产生携带未重排的人类kappa基因的大片段 并培育成二期重链小鼠。这些老鼠将被培育成 缺乏功能性免疫球蛋白基因的小鼠产生小鼠演示 广泛的高亲和力，完全是人类抗体的曲目。

The goal of GenPharm's program is to develop methods for the introduction of yeast artificial chromosomes (YACs) into the germline of mice, and to apply the technology toward the generation of transgenic mice expressing a broad, fully human immunoglobulin repertoire. These mice would permit the isolation of human monoclonal antibodies in an analogous manner to rodent monoclonal antibodies. In Phase I, methods for the introduction of YACs into mice were developed, and mice carrying a small YAC encoding a minimally competent human immunoglobulin transgene were shown to express human heavy chain IgM antibodies in the serum. In Phase II, the animals generated in Phase I will be fully characterized for transgene function and expression. Additional constant and variable regions will be cloned in YACs and added to the Phase I YAC to permit class switching, somatic mutation, and IgGproduction. These Phase II transgenes will be introduced into mice using methodology developed in Phase I. Transgenic mice will also be generated carrying large fragments of the unrearranged human kappa gene and bred to the Phase II heavy chain mice. These mice will be bred with mice lacking functional immunoglobulin genes to produce mice demonstrating a broad repertoire of high affinity, fully human antibodies.