Natori T, Ohhashi T, Inomata T, Fujimoto Y, Ishida Y, Kasahara M, Aizawa M
J Immunogenet. 1983 Dec;10(6):439-52. doi: 10.1111/j.1744-313x.1983.tb01031.x.
The RT1-B/D region-associated antigens which were serologically defined in the previous study (Ohhashi et al., 1981), were partially purified from membranes of a rat B cell leukaemia, KNL-14. Sequential immunoprecipitation test, with the partially purified 125I-B/Dak preparation using four different rat alloantisera, including a monoclonal antibody, disclosed three distinctive populations of beta units of the class II molecules. Highly purified beta units of three discriminable class II molecules were shown to have different structural properties in terms of molecular weights and of electrophoretic profiles on the isoelectric focusing. The beta units shifted to a position of higher molecular weight on SDS-PAGE under reducing condition, thus suggesting to carry intradisulfide bonds. Furthermore, the highly purified beta units cross-reacted with murine anti-Ia sera. The rebinding test revealed that at least two discriminable species of beta units cross-react with anti-I-Ak monoclonal antibody, whereas beta units purified by binding with the 1E4 monoclonal antibody cross-reacted with anti-I-Ab and/or anti-I-Ad antiserum. On the basis of structural and antigenic properties, we have postulated that the rat class II region can be divided into at least three subregions, each containing a locus which encodes a distinctive beta unit of the class II molecule.
在先前研究（Ohhashi等人，1981年）中通过血清学定义的RT1-B/D区域相关抗原，从大鼠B细胞白血病KNL-14的膜中进行了部分纯化。使用包括单克隆抗体在内的四种不同大鼠同种异体抗血清，对部分纯化的125I-B/Dak制剂进行连续免疫沉淀试验，揭示了II类分子β亚基的三个不同群体。三种可区分的II类分子的高度纯化β亚基在分子量和等电聚焦电泳图谱方面显示出不同的结构特性。在还原条件下，β亚基在SDS-PAGE上迁移到较高分子量的位置，因此表明携带链内二硫键。此外，高度纯化的β亚基与小鼠抗Ia血清发生交叉反应。再结合试验表明，至少两种可区分的β亚基物种与抗I-Ak单克隆抗体发生交叉反应，而通过与1E4单克隆抗体结合纯化的β亚基与抗I-Ab和/或抗I-Ad抗血清发生交叉反应。基于结构和抗原特性，我们推测大鼠II类区域可至少分为三个亚区域，每个亚区域包含一个编码II类分子独特β亚基的基因座。
