McKeever P E, Kim K J, Nero G B, Laskov R, Merwin R M, Logan W J, Asofsky R
J Immunol. 1979 Apr;122(4):1261-5.
Spontaneous lymphomas of BALB/c mice, both in vivo tumors and cell lines established in long term tissue cultures, were investigated for their ability to synthesize IgM by using radiolabeled amino acid precursors. Immunoglobulins manufactured by lymphomas K46 and L10A had the m.w. of monomeric IgM and IgM half molecule. Both of these molecules could be immunoprecipitated with class-specific anti-IgM but not anti-IgA or anti-IgG. When precipitated with polyvalent anti-Ig L10A synthesized monomeric immunoglobulins that migrated as two peaks in contrast to their single counterpart precipitated with anti-IgM. The second peak migrated in the region expected for IgD. Monomer and half molecules were composed of similar ratios of mu-chains to light chains linked by disulfide bonds. The mu2L2 monomer of these B cell lines migrated slightly slower in SDS PAGE than a mu2L2 secreted by a myeloma. Thus, these lymphomas synthesize immunoglobulins with the chemical and antigenic characteristics typical of monomeric membrane-attached IgM and IgM half molecules, plus a molecule resembling IgD on L10A only. Lymphoma assembly of monomeric IgM may follow the same initial biosynthetic sequence as myeloma assembly.
利用放射性标记的氨基酸前体，研究了BALB/c小鼠的自发性淋巴瘤（包括体内肿瘤和长期组织培养建立的细胞系）合成IgM的能力。淋巴瘤K46和L10A产生的免疫球蛋白具有单体IgM和IgM半分子的分子量。这两种分子都能用类特异性抗IgM进行免疫沉淀，但不能用抗IgA或抗IgG沉淀。用多价抗Ig沉淀时，L10A合成的单体免疫球蛋白迁移为两个峰，与其用抗IgM沉淀的单一对应物形成对比。第二个峰在预期的IgD区域迁移。单体和半分子由通过二硫键连接的μ链与轻链的相似比例组成。这些B细胞系的μ2L2单体在SDS-PAGE中迁移速度比骨髓瘤分泌的μ2L2略慢。因此，这些淋巴瘤合成的免疫球蛋白具有单体膜结合IgM和IgM半分子典型的化学和抗原特性，此外，仅在L10A上有一个类似IgD的分子。单体IgM的淋巴瘤组装可能遵循与骨髓瘤组装相同的初始生物合成序列。
