Rath S, Durdik J, Gerstein R M, Selsing E, Nisonoff A
Department of Biology, Brandeis University, Waltham, MA 02254-9110.
J Immunol. 1989 Sep 15;143(6):2074-80.
Analysis of C57BL/6 mice (IgM allotype, Igh-6b or mu b) that carry an Ig H chain transgene of a different allotype (mu a) shows that IgM molecules of mixed allotype (mu a mu b) are present among serum antibodies. The finding was extended to hybridomas prepared from nonimmune transgenic mice, many of which also failed to exhibit allelic exclusion. The proportions of mu a and mu b secreted by individual hybridomas varied markedly, and the product of an individual hybridoma was found to be heterogeneous with respect to the allotype content of individual molecules. The ratio of mu a:mu b chains secreted by individual hybridomas was found to correlate with the number of transgene copies remaining in each hybridoma, and several hybridomas that secrete only mu b-positive molecules had apparently lost all but one copy of the transgene. An idiotype characteristic of the transgene was found to be present only in association with the transgenic (mu a) allotype, and indirect evidence strongly suggests that the idiotype was present only on mu a polypeptide chains. Thus, there is no evidence in this system for the induction of idiotypically cross-reactive endogenous molecules.
对携带不同同种异型（μa）的Ig H链转基因的C57BL/6小鼠（IgM同种异型，Igh-6b或μb）进行分析，结果显示血清抗体中存在混合同种异型（μaμb）的IgM分子。这一发现扩展到了从非免疫转基因小鼠制备的杂交瘤，其中许多也未能表现出等位基因排斥。各个杂交瘤分泌的μa和μb比例差异显著，并且发现单个杂交瘤的产物在单个分子的同种异型含量方面是异质的。发现各个杂交瘤分泌的μa:μb链比例与每个杂交瘤中剩余的转基因拷贝数相关，并且一些仅分泌μb阳性分子的杂交瘤显然除了一个转基因拷贝外其余都已丢失。发现转基因特有的独特型仅与转基因（μa）同种异型相关，并且间接证据强烈表明该独特型仅存在于μa多肽链上。因此，在这个系统中没有证据表明存在独特型交叉反应性内源性分子的诱导。
