Abstract
We report that four systemic lupus erythematosus (SLE) patient sera containing anti-dsDNA antibodies, three affinity-purified anti-dsDNA IgG, and a human anti-dsDNA MoAb (33.H11) immunoprecipitate 18S ribosomal RNA from DNase-treated 32P-labelled MOLT4 cell extract. This 18S RNA precipitation was inhibited completely by preincubating 33.H11 with calf thymus dsDNA or the recombinant human ribosomal protein S1, which was reported to cross-react with anti-dsDNA antibodies (J Immunol 1996; 156:1668-75). Whole IgG from three SLE sera with anti-dsDNA antibodies, 33.H11, and three affinity-purified anti-dsDNA IgG inhibited in vitro translation of globin mRNA (percent inhibition was 36-50%). This translation inhibition by anti-dsDNA antibodies was enhanced (67-79%) when the reticulocyte lysate was treated with DNase. Suppression of protein synthesis could be a pathogenic mechanism of anti-dsDNA antibodies, since it has also been shown that anti-dsDNA penetrates living cells (J Immunol 1995; 154:4857-64) in culture.