Rheumatoid factors from patients with rheumatoid arthritis react with tryptophan 60 and 95, lysine 58, and arginine 97, on human beta 2-microglobulin.
OBJECTIVE
To define precise epitopes on human beta 2-microglobulin (beta 2m) reacting with polyclonal IgM rheumatoid factors (RF) from patients with rheumatoid arthritis (RA).


METHODS
Ten polyclonal RF were tested for their human beta 2m epitope-binding specificities using the entire 99-amino acid sequence synthesized as overlapping 7-mers in an enzyme-linked immunosorbent assay. Glycine substitution for each residue within RF-reacting linear regions was employed to define major reactive sites.


CONCLUSIONS
Major beta 2m residues contributing to RF reactivity were tryptophans at positions 60 and 95, lysine at 58, and arginine at position 97.
Williams
R C
RC
Department of Medicine, University of Florida College of Medicine, Gainesville 32610.
Malone
C C
CC
Harley
J B
JB
D000595:Amino Acid Sequence; D000918:Antibody Specificity; D001120:Arginine / Q000032:analysis*; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000276:immunology*; D001224:Aspartic Acid / Q000032:analysis; D002846:Chromatography, Affinity; D003201:Computers; D000939:Epitopes / Q000032:analysis; D006801:Humans; D007070:Immunoglobulin A / Q000737:chemistry / Q000276:immunology; D007141:Immunoglobulin Fc Fragments / Q000032:analysis; D007074:Immunoglobulin G / Q000737:chemistry / Q000276:immunology; D007075:Immunoglobulin M / Q000737:chemistry / Q000276:immunology; D007532:Isoleucine / Q000032:analysis; D008239:Lysine / Q000032:analysis*; D008969:Molecular Sequence Data; D012217:Rheumatoid Factor / Q000032:analysis* / Q000276:immunology; D017386:Sequence Homology, Amino Acid; D014364:Tryptophan / Q000032:analysis*; D014633:Valine / Q000032:analysis; D001613:beta 2-Microglobulin / Q000737:chemistry* / Q000276:immunology
D000939:Epitopes; D007070:Immunoglobulin A; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D001613:beta 2-Microglobulin; D007532:Isoleucine; D001224:Aspartic Acid; D014364:Tryptophan; D012217:Rheumatoid Factor; D001120:Arginine; D014633:Valine; D008239:Lysine