Jang Y J, Lecerf J M, Stollar B D
Department of Biochemistry, Tufts University School of Medicine, Boston, MA 02111, USA.
Mol Immunol. 1996 Feb;33(2):197-210. doi: 10.1016/0161-5890(95)00094-1.
Antibodies H241 and 2C10 are lupus mouse IgG autoantibodies that bind native DNA. In previous experiments, oligonucleotide antigens affinity-labeled both H and L chains of H241 but only the H chain of antibody 2C10. Primary structures of the V regions of the 2C10 H and L chains and the H241 L chain, determined from cDNA, help to explain the previous affinity-labeling experiments. The 2C10 L chain CDRs had several Asp residues and a net negative charge of five, whereas the 2C10 H chain CDRs had four Arg residues and a net positive charge of five. The L chain CDRs of H241 had a net positive charge of one. [The H241 H chain cDNA sequence was published previously by Gangemi et al. (1993) J. Immun. 151, 4660-4671]. Plasmid vectors were used for bacterial expression of H and L chains of 2C10 alone and in combinations in single chain Fv (scFv) molecules. The H chain alone bound native DNA as well as or better than the H-plus-L chain scFv. The H chain alone also bound Z-DNA. Combination of the 2C10 H chain with the L chain of an anti-Z-DNA antibody maintained the selectivity for Z-DNA, whereas its combination with the 2C10 L chain (in the 2C10 Fab) yielded selective B-DNA binding. The results with 2C10 match other examples in which the H chain is sufficient for DNA binding but selectivity is modulated by the L chain. The H chain binding to autoantigen may reflect selective events in early stages of B cell development.
抗体H241和2C10是结合天然DNA的狼疮小鼠IgG自身抗体。在先前的实验中，寡核苷酸抗原对H241的重链和轻链都进行了亲和标记，但仅对抗体2C10的重链进行了亲和标记。从cDNA确定的2C10重链和轻链以及H241轻链V区的一级结构有助于解释先前的亲和标记实验。2C10轻链互补决定区（CDR）有几个天冬氨酸残基，净负电荷为5，而2C10重链CDR有4个精氨酸残基，净正电荷为5。H241的轻链CDR净正电荷为1。[H241重链cDNA序列先前已由Gangemi等人发表（1993年，《免疫学杂志》151卷，4660 - 4671页）]。质粒载体用于单独表达2C10的重链和轻链，并将它们组合成单链Fv（scFv）分子。单独的重链结合天然DNA的能力与重链加轻链的scFv相当或更好。单独的重链也能结合Z - DNA。2C10重链与抗Z - DNA抗体的轻链结合可保持对Z - DNA的选择性，而它与2C10轻链结合（在2C10 Fab中）则产生对B - DNA的选择性结合。2C10的结果与其他例子相符，即重链足以结合DNA，但选择性由轻链调节。重链与自身抗原的结合可能反映了B细胞发育早期的选择性事件。
