Thymine and guanine base specificity of human myeloma proteins with anti-DNA activity.

Abstract

To further our understanding of the molecular basis of DNAautoantibody interactions, we have characterized the specificities of three IgG human myeloma proteins that bind DNA. We measured their binding to synthetic single-and double-stranded homopolynucleotides, random and alternating copolymers, oligonucleotides, and nucleotides or nucleosides conjugated to nonnucleic acid carriers. All three antibodies bound single-stranded nucleic acids, including both polyribonucleotides and polydeoxyribonucleotides. They varied in relative affinities for polynucleotides of varying base composition. Polymers containing the purines guanine or hypoxanthine and/or the pyrimidine thymine were most reactive with all three proteins. A myeloma protein that reacted with poly(G), poly(I), or poly(dT) also bound to the corresponding nucleosides or nucleotides conjugated to bovine serum albumin. None of the antibodies reacted with base-paired double-helical polynucleotides (double-stranded RNA, RNA-DNA hybrid or double-stranded DNA). The results indicate that base specificity is prominent in their reactions and that the accessible epitopes in single-stranded polynucleotides become masked upon base pairing in double-stranded helices. These findings suggest a model in which positions N1 and 06 of guanine and hypoxanthine and N3 and 04 of thymine interact with amino acids of the antibody-combining site.

Enhanced antibody titers to an oxidized DNA base in inflammatory and neoplastic diseases

“…However, our results point to the 5hydroxytnethyl group of HMU as being the preferred epitope to the 5-tnethyl group of thytnine. We also established that HMdU atid dT tnust be coupled to BSA in order to inhibit serutn binding to the appropriate antigen-coated wells, whereas free HMdU and dT are not inhibitory (17), This is agaiti parallel to the results of Zouali atid Stollar (28), who showed that dT-BSA does inhibit this type of binding while free thymidine does not. So, it appears that ROS not only cause oxidation of bases in DNA but also cause DNA denaturation and hydrolysis of sotne bonds iti the sugar-phosphate backbone, which could lead to a release of DNA fragments.…”

“…The lytnphocytes of healthy individuals were shown to respond to sotne tnitogens with production of Ab which share idiotypic detertninants with those generated by lupus patients (27). Moreover, Zouali and StoUar (28) found that the thytnine moiety present in singlestranded DNA, poly dT or dT-BSA is recognized by 3 tnyelotna proteins, the specificities of which are sitnilar to the anti-DNA Ab occurring in the sera of lupus patients. Hence, our finding of Ab that recognize the thytnine residue present in thytniditie coupled to BSA parallels those of ZouaH and StoUar.…”

Origin and Diversification of Anti‐DNA Antibodies

“…Of particular interest is that some of the "normal" monoclonal autoantibodies have binding properties similar to those derived from SLE patients. The antigen binding properties of certain human myeloma proteins also resemble those of polyclonal and monoclonal anti-DNA antibodies of autoimmune sera (Fermand et al 1985, Naparstek et al 1985, Zouali & Stollar 1986, and may even express human lupus anti-DNA-related idiotopes , Shoenfeld et al 1986. Thus, it appears that autoantibodies present in lupus sera share features with immunoglobulins produced by neoplastic B cells and by monoclonal antibodies "captured" from normal subjects by the hybridoma technique.…”

Effects of intravenous immunoglobulin on alpha synuclein aggregation and neurotoxicity

“…# BP078; concentration =1 mg/ml). (HMP are spontaneously arising monoclonal antibodies found in sera of patients with lymphoproliferative disorders such as multiple myeloma and Waldenstrom's macroglobulinemia [41]; their antigenic specificity is generally unknown. Using our previously published ELISA [34], we did not detect anti-α-synuclein antibodies in HMP [data not shown].)…”