Analysis of autoantibody production and regulation system using monoclonal anti-DNA antibodies

利用体细胞杂交技术，我们建立了14株产生抗DNA抗体的杂交瘤细胞。根据我们所有的数据，与DNA反应的抗体基本上可以分为两类。一种是与单链DNA反应的抗体，这种抗体对DNA碱基具有有限的特异性。另一类抗体具有血清多态特性，可与多种多核苷酸反应，包括单链DNA、双链DNA和合成RNA。我们选择了三种针对多聚(DG)的抗单链DNA单抗，并试图通过半抗原抑制试验进一步阐明核酸抗原决定簇的精确特异性。结果表明，抗单链DNA单抗识别的是核酸的一级碱基序列，而不是核酸的三级结构，多聚(DG)特异性杂交瘤抗体对核酸的碱基和糖基部分具有特异性，磷酸…DNA的更多部分可能对单链DNA表位的形成贡献很小。我们的数据还表明，单链DNA的最大抗原大小对应于四核苷酸或五核苷酸。我们观察到多特异性抗DNA抗体(抗ss/dsDNA)可与心磷脂发生交叉反应，其化学结构类似于多核苷酸骨架。梅毒生物假阳性血清学试验(BFP-STS)是公认的SLE患者的特征，而心磷脂是STS的主要抗原。因此，推测SLE血清中的BFP反应是由于具有与单链DNA、双链DNA和心磷脂反应的抗体所致。然而，没有检测到能够与DNA和VDRL抗原结合的杂交瘤。所有这些发现综合起来，提出了抗DNA抗体可以与心磷脂结合，因为核酸骨架有相似的结构，但不同于BFP反应。较少

Using the somatic cell hybridization technique, we have established 14 hybridomas which produces antibodies to DNA. On the basis of all our data, antibdies reacting with DNA can be basically classified into two groups. One includes antibodies which react exclusively with ssDNA and which have a restricted specificity to DNA base. The other includes antibodies which are serologically polymorphic in that they can react with a variety of polynucleotides including ssDNA, dsDNA and synthetic RNA.We selected three anti-ssDNA monoclonal antibodies specific for poly(dG) and attempted to further elucidate the precise specificity of antigenic determinants of nucleic acids using a hapten inhibition assay. We obtained the results that the anti-ssDNA monoclonal antibody recognized the primary base sequences rather than the tertiary structure of nucleic acids, that the poly(dG) specific hybridoma antibodies had specificity restricted to the base and sugar part of nucleic acids and that the phosphate … More part of DNA may contribute little to the epitope formation of ssDNA. Our data also suggest the mnimal antigenic size of ssDNA corresponds to the tetra- or pentanucleotide.We observed that polyspecific anti-DNA antibodies (anti-ss/dsDNA) could cross-react with cardiolipn, the chemical structure of which is similar to that of polynucleotide backbone. A biological false positive serological test for syphilis (BFP-STS) is a well recognized characteristic of patients with SLE and cardiolipin is a major antigen in the STS. Therefore, it iwas assumed that the BFP reactors in SLE sera were due to the antibodies which had the ability to react with ssDNA, dsDNA and cardiolipin. However, hybridoma capable of binding to both DNA and the VDRL antigen were not detectable.All these findings taken together lead the proposal that anti-DNA antibodies which react with common antigenic determinants on the phosphate-sugar backbone of nucleic acid can bind to the cardiolipn, as there is a structural similarity in the nucleic acid backbone, but differ from the BFP reactors. Less