Cytoskeletal binding of monoclonal anti-DNA antibodies derived from tonsillar lymphoid cells of a normal subject.

The ability of monoclonal IgM anti-DNA autoantibodies 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.