Antibody-nucleic acid complexes. Oligo(dG)n and -(dT)n specificities associated with anti-DNA antibodies from autoimmune MRL mice.
The specificity of anti-DNA antibodies in the sera of unimmunized autoimmune MRL mice was initially assessed via an enzyme-linked immunosorbent assay (ELISA). Antibody binding profiles to a panel of immobilized antigens (AMP-, GMP-, CMP-, UMP-, and TMP-BSA, ss- and dsDNA) demonstrated high levels of immunoglobulins reacting with GMP and ssDNA and intermediate levels with AMP, TMP, and dsDNA. Fractionation of serum anti-DNA antibodies into subsets on the basis of their binding to GMP- and TMP-agarose indicated that the resulting GMP- or TMP-reactive antibodies bound to their homologous nucleotides and ssDNA. Competition-inhibition studies with soluble mono-, oligo-, and polynucleotides revealed that GMP- and TMP-reactive antibodies were highly specific for oligo(dG)n and -(dT)n sequences, respectively. Whereas the relative affinity of TMP-reactive autoantibodies to oligo(dT)n increased with oligonucleotide length (n = 2, 4, 6, 8, 10, 15), GMP-reactive antibodies preferentially recognized oligo(dG)10 (Ka congruent to 1 x 10(7) M-1). While neither antibody recognized oligo(dA)8 and -(dC)8 competitors, mixed-base oligonucleotides were inhibitory at concentrations approximately 10-fold greater than similarly sized oligo(dG)n and -(dT)n sequences. Similar characterizations of both pooled and individual MRL sera indicated that anti-DNA antibodies represent 8-10% of the total serum IgG. More importantly, GMP-reactive autoantibodies predominated and accounted for 60-70% of the entire unbound anti-DNA antibody population.
Munns
T W
TW
Rheumatology Division, Washington University School of Medicine, St. Louis, Missouri 63110.
Freeman
S K
SK
D000818:Animals; D000906:Antibodies / Q000302:isolation & purification*; D000915:Antibody Affinity; D000918:Antibody Specificity; D000941:Antigens / Q000276:immunology; D001323:Autoantibodies / Q000097:blood; D004247:DNA / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006157:Guanosine Monophosphate / Q000276:immunology; D005779:Immunodiffusion; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009838:Oligodeoxyribonucleotides / Q000276:immunology; D009841:Oligonucleotides / Q000276:immunology; D011119:Polynucleotides / Q000276:immunology; D012685:Sepharose; D013938:Thymidine Monophosphate / Q000276:immunology
D000906:Antibodies; D000941:Antigens; D001323:Autoantibodies; D009838:Oligodeoxyribonucleotides; D009841:Oligonucleotides; D011119:Polynucleotides; C027903:oligo (dT); C033538:oligodeoxyguanylic acid; D013938:Thymidine Monophosphate; D006157:Guanosine Monophosphate; D004247:DNA; D012685:Sepharose