Human anti-p68 autoantibodies recognize a common epitope of U1 RNA containing small nuclear ribonucleoprotein and influenza B virus.
Autoantibodies from patients with systemic rheumatic diseases were used to map antigenic sites on the 68-kD autoantigen (p68) associated with (U1)RNA-containing small nuclear ribonucleoprotein (snRNP) particles. With truncated recombinant fusion proteins and synthetic peptides, a subset of anti-p68 autoantibodies was found to recognize the amino acid sequence motif Glu-Arg-Lys-Arg-Arg (ERKRR). To investigate the possible involvement of epitopes shared by microbial antigens and host self-components in initiation of autoimmunity (molecular mimicry), a sequence data bank was screened for proteins containing an amino acid motif identical or related to ERKRR. The identical motif was found on the M1 matrix protein of influenza B viruses, and affinity-purified human anti-ERKRR autoantibodies recognized this epitope also in the viral amino acid sequence context. The common epitope recognized by human autoantibodies suggests that influenza B virus infection may play a role in initiation of the anti-p68 and anti-(U1)RNP autoimmune response.
Max-Planck-Institut für Biochemie, Martinsried, Federal Republic of Germany.
H H
HH
Guldner
H J
HJ
Netter
C
C
Szostecki
E
E
Jaeger
H
H
Will
D000818:Animals; D001323:Autoantibodies / Q000276:immunology*; D003429:Cross Reactions; D000939:Epitopes / Q000032:analysis*; D005260:Female; D006801:Humans; D007114:Immunization; D009981:Influenza B virus / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D012261:Ribonucleoproteins / Q000276:immunology*; D017411:Ribonucleoproteins, Small Nuclear; D014763:Viral Matrix Proteins / Q000276:immunology*
D001323:Autoantibodies; D000939:Epitopes; D012261:Ribonucleoproteins; D017411:Ribonucleoproteins, Small Nuclear; D014763:Viral Matrix Proteins