Ayadi H, Mihaesco E, Congy N, Roy J P, Gendron M C, Laperriere J, Prelli F, Frangione B, Brouet J C
Institut National de la Santé et de la Recherche Médicale Unité 108, Hôpital Saint-Louis, Paris, France.
J Immunol. 1992 May 1;148(9):2812-6.
The amino acid sequence corresponding to the V region H chain gene used by three monoclonal IgM directed to the myelin-associated glycoprotein (MAG) is presented. They all belonged to the VHIII variability subgroup, but each may well represent a new member of this family inasmuch as their homology with previously sequenced VHIII genes was less than 80%. Strikingly, there was no greater homology between the H chain V regions of the anti-MAG IgM. Partial amino acid sequence data indicated that these V regions were joined to as yet unidentified DH segments; however, two H chains used very similar DH, possibly indicating that this sequence was involved in the fine specificity of the IgM for MAG. All H chains included a JHIV region. These data, together with results obtained from the sequence of the three kappa L chains of the same IgM molecules (Mihaesco, E., H. Ayadi, N. Congy, M. C. Gendron, J. P. Roy, H. Heyermann, B. Frangione, and J. C. Brouet. 1989. J. Biol. Chem. 264:21481), indicate that the repertoire of VL and VH gene segments used by anti-MAG IgM is quite diverse, in contrast to previous structural data obtained for other human monoclonal IgM autoantibodies. Possibly, these differences reflect distinct pathogenesis.
本文展示了三种针对髓鞘相关糖蛋白（MAG）的单克隆IgM所使用的与重链可变区（V区）基因相对应的氨基酸序列。它们均属于VHIII可变亚组，但由于它们与先前测序的VHIII基因的同源性低于80%，因此每个序列很可能代表该家族的一个新成员。引人注目的是，抗MAG IgM的重链V区之间的同源性并不更高。部分氨基酸序列数据表明，这些V区与尚未确定的重链多样性（DH）基因片段相连；然而，两条重链使用了非常相似的DH，这可能表明该序列与IgM对MAG的精细特异性有关。所有重链均包含一个JHIV区。这些数据，连同从相同IgM分子的三条κ轻链序列中获得的结果（Mihaesco, E., H. Ayadi, N. Congy, M. C. Gendron, J. P. Roy, H. Heyermann, B. Frangione, and J. C. Brouet. 1989. J. Biol. Chem. 264:21481），表明抗MAG IgM所使用的VL和VH基因片段库相当多样，这与先前针对其他人类单克隆IgM自身抗体获得的结构数据形成对比。这些差异可能反映了不同的发病机制。
