A ribonucleic acid‐specific antibody produced during autoimmune disease: evidence for nucleotide sequence specificity

A hybridoma secreting RNA‐binding autoantibody has been produced by fusion of spleen cells from autoimmune NZB/NZW F₁ mice with drug‐resistant IgG_2b,‐producing myeloma cells from BALB/c mice. Studies on the specificity of the purified monoclonal autoantibody revealed: (a) absolute specificity for ribopolynucleotides as compared with deoxyribopolynucleotides; (b) specificity for single‐stranded RNA as compared with double‐stranded RNA; (c) high affinity for the random copolymer poly(G, C); and (d) preference for the random heteropolymer poly(G, C, U). These studies were complemented by stoichiometric measurements of the antibody‐RNA complex and computer analysis of the abundance of various di‐, tri‐and tetranucleotide sequences in native RNA. Taken together, these data suggest that the anti‐genie determinant recognized by the monoclonal autoantibody is largely composed of a trinucleotide sequence of single‐stranded RNA containing G, C and U residues.