Monoclonal murine anti‐dna antibody interacts with living mononuclear cells

Abstract

A monoclonal mouse antibody, 4-B-5, that reacted with both single-stranded DNA (ssDNA) and double-stranded DNA showed direct reactivity and cell association with mouse thymocytes, as well as peripheral blood mononuclear cells. Absorption of 4-B-5 with peripheral blood mononuclear cells or with mouse thymocytes markedly reduced reactivity with both ssDNA and double-stranded DNA. However, treatment of mouse thymocytes or human T cells with DNase completely eliminated monoclonal anti-DNA reactivity with cells. The cellular reactivity was completely restored when monoclonal anti-DNA was incubated with DNase-treated cells in the presence of normal human serum. Normal human serum was found to contain 574 f 639 ng/ml of ssDNA. Coincubation or cell preincubation of mouse thymocytes with ssDNA produced a marked increase in 4-B-5 cell association. These findings indicate that mouse monoclonal anti-DNA can react with and can penetrate both mouse and human mononuclear cells, and that this reactivity may depend on the presence of cell membrane DNA on both types of target cells.Previous studies from our laboratory have indicated that some sera from patients with systemic lupus Address reprint requests to Ralph C. Williams, Jr., MD, University of New Mexico School of Medicine, Albuquerque, NM 87131.Submitted for publication May 15, 1986; accepted in revised form October 2. 1986. erythematosus (SLE) contain IgG antilymphocyte antibodies which associate with T cells during in vitro culture and appear to penetrate cell membranes, as well as the inner cytosol of such living cells (1). The exact mechanism of how such IgG antibody reacts with T cell membranes and appears to enter cells without initially killing them is still not clear. It seemed possible that antinuclear antibodies might somehow react directly or cross-react with epitopes present on T cell membranes, and that this sort of cross-specificity might be involved in the eventual IgG cell membrane association.Recent observations support the idea that monoclonal anti-DNA antibodies may show a considerable degree of polyspecificity. Lafer et al(2) showed that such monoclonal lupus antibodies produced reactions with both polynucleotides and phospholipids. Jacob and coworkers (3) have subsequently demonstrated that monoclonal murine anti-DNA antibody binds to cell surface proteins which are not destroyed by DNase treatment. Moreover, these investigators have recently shown that monoclonal murine anti-DNA autoantibody binds to identical proteins present on human glomeruli, platelets, erythrocytes, T and B cells, and even neuronal tissue (4). This striking crossreactivity might somehow be associated with IgG anti-DNA T cell association in patients with SLE. This report describes our results measuring living mouse thymocyte or human peripheral blood mononuclear cell (PBMC) association with a panel of murine monoclonal IgG anti-DNA antibodies of varying specificity.

Receptor-mediated cellular entry of nuclear localizing anti-DNA antibodies via myosin 1.

“…By inference, therefore, if it is not pathogenic it is not worth studying. Nevertheless, we and others have found the observation intriguing and worthy of investigation, reasoning that the phenomenon may have more general biologic significance, whether or not it is pathogenically relevant (5)(6)(7)(8)(9)(10).…”

Antibody penetration of viable human cells. I. Increased penetration of human lymphocytes by anti-RNP IgG

“…There was no statistical difTerence when anti-RNP IgG was compared wivh anU-dsDNA IgG (Table 2>. There are already some data to suggest that anti-dsDNA antibody can penetrate viable lymphocytes by binding to DNA on the cell surface (Okudaira et al, 1987).…”

“…1979c, 1982Alarcon-Segovia & Llorente, 1983), Antinuclearantibody penetration of living lymphocytes was also reported by the others. Okudaira et al (1987) have shown that, after stripping IgG from cell surface, mouse monoclonal anti-DNA antibodies could still be detected within cell extracts when mouse and normal human PBMC were incubated with monoclonal anti-DNA antibodies for a period of over 15 h. Under the micro.scope, approximately 10' !^i of T lymphocytes showed peroxidase-positive pcrinuciear staining or actual intranuclear globular staining. They assumed that anli-DNA antibodies might penetrate living cells.…”

“…1979bAlarcon-Segovia, Ruiz-Arguelles & Llorente. 1979c;Alarcon-Segovia, Llorente & Ruiz-Arguelles, 1982;AlarconSegovia & Llorente, 1983;Okudaira, Yoshizawa & Williams. 1987).…”

DNA–histone complexes as ligands amplify cell penetration and nuclear targeting of anti‐DNA antibodies via energy‐independent mechanisms

“…7,8 Polyreactivity has been associated with the presence of positively charged amino acids in the CDR2 and CDR3 regions of CPAbs, 7 favouring interactions with negatively charged cell membrane components such as heparin sulphate 9,10 and collagen type IV. 11 To date, most CPAbs described in the literature have been shown to enter cells through endocytic pathways requiring energy, 4,[12][13][14][15][16][17][18][19] but a few CPAbs have been reported to use energy-indeAbbreviations: a.u., arbitrary units; CPAbs, cell-penetrating antibodies; DHC, DNA-histone complexes; mAb, monoclonal antibody; SLE, systemic lupus erythematous; TNP-BSA, trinitrophenyl-bovine serum albumin…”