Cytoskeletal binding of monoclonal anti‐dna antibodies derived from tonsillar lymphoid cells of a normal subject

Abstract

The ability of monoclonal IgM anti‐DNA auto‐antibodies derived from normal human lymphoid cells to bind to cellular constituents of human epithelial cells (HEp‐2) was examined by immunofluorescence. Hybridoma supernatants from 10 different clones were studied. Four of them gave a strong fibrillar cytoplasmic staining that resembled cytoskeletal staining, 1 showed strong nuclear staining only, 3 showed weak nucleolar staining only, and 2 showed no staining. The hybridoma supernatants that reacted with HEp‐2 cytoskeleton were either polyspecific for various nucleic acid antigens, such as single‐stranded DNA, DNA, poly(dA:dT), poly(dG)·poly(dC), RNA, and cardiolipin, or were restricted to cardiolipin. Cytoskeletal staining identical to the hybridoma supernatant staining was also seen with mouse monoclonal anti‐vimentin antibody B11.5.1. Inhibition of the cytoskeletal staining was accomplished in 3 of the 4 hybridoma supernatants by preabsorption of these hybridoma supernatants with cardiolipin and/or single‐stranded DNA, or by preincubation of the HEp‐2 cells with the mouse monoclonal anti‐vimentin antibody.

Expression in systemic lupus erythematosus of an idiotype common to DNA-binding and nonbinding monoclonal antibodies produced by normal human lymphoid cells.

“…The generation of anti-DNA antibody responses was demonstrated in cultures of peripheral blood lymphocytes (1,2), normal tonsillar lymphocytes (1), in a human:human hybridoma system derived from lymphoid cells of normal individuals (3)(4)(5) and in nonautoimmune strains of mice (6,7). These normal-derived anti-DNA antibodies are qualitatively identical to those produced in SLE in that they exhibit an identical spectrum of antigen binding characteristics in which not only nucleic acid antigens are included but also human IgG, cardiolipin, and vimentin (1,(8)(9)(10).…”