Purification and characterization of natural antibodies that recognize a human brain lectin.
We have recently identified oligoclonal IgG antibodies that are related to a human brain lectin (HBL14) from serum and cerebrospinal fluid of patients with neurological disorders. They were termed lectin-like IgG (L-IgG) (Joubert-Caron et al., 1994a,b). In this paper, the occurrence of antibodies reactive both towards HBL14 and L-IgG was investigated. Binding of antibodies to HBL14 was demonstrated by solid-phase ELISA and chromatography on immobilized HBL14. Fab fragments of these antibodies were also shown to bind to HBL14. The specificity of the antibodies towards HBL14 was studied using a panel of different antigens. Our data show that individual sera from healthy people as well as a pool of immunoglobulins from 80 blood donors contain an IgG autoreactivity to HBL14, while no IgM autoreactivity was detected. Anti-HBL14 antibodies from sera were purified using affinity chromatography on immobilized HBL14. Affinity chromatography further allowed us to demonstrate that the binding of anti-HB14 antibodies was mediated through their Fab fragments. A higher amount of anti-HBL14 antibodies was purified using a L-IgG-depleted fraction of sera. The binding of anti-HBL14 antibodies to L-IgG was confirmed by ELISA. Finally, anti-HBL14 antibodies were found to be polyreactive. These results indicate the occurrence of a novel class of natural antibodies reactive towards a human brain lectin and suggest that these antibodies may participate in immunoregulatory mechanisms probably though idiotypic/anti-idiotypic interaction.
Lutomski
D
D
Laboratoire de Biochimie et Technologie des Protéines, Université Paris-Nord, UFR SMBH Léonard de Vinci, Bobigny, France.
Caron
M
M
Bourin
P
P
Lefebure
C
C
Bladier
D
D
Joubert-Caron
R
R
D000918:Antibody Specificity; D001323:Autoantibodies / Q000276:immunology / Q000302:isolation & purification*; D001923:Brain Chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000276:immunology; D007074:Immunoglobulin G / Q000302:isolation & purification; D037102:Lectins / Q000276:immunology*; D009419:Nerve Tissue Proteins / Q000276:immunology*
D001323:Autoantibodies; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D037102:Lectins; D009419:Nerve Tissue Proteins