Identification of the B-cell epitopes of the early endosome antigen 1 (EEA1).
Early endosome antigen 1 (EEA1) is a target autoantigen in patients diagnosed with neurological and other autoimmune conditions. Eighteen of 65 sera (28%) that displayed a vesicular cytoplasmic staining pattern also immunoprecipitated the recombinant EEA1. These 18 sera were selected for further clinical, serological and epitope mapping studies. Thirty-six percent of the 18 patients had neurological diseases. Seventeen sera (94%) reacted with the partial length EEA1 constructs that included the C-terminal zinc finger (+FYVE) and the methyl accepting domain (LeuMA: amino acids 82-1411) in an addressable laser bead assay suggesting that the assay may be used for rapid laboratory detection of anti-EEA1 antibodies. Three of seven sera selected for epitope mapping studies bound to EEA1 peptides represented by amino acids 1096-1125, and two reacted with peptides represented by amino acids 1296-1320. One serum reacted only with the C-terminal peptide 1096-1125. The remaining serum reacted with other EEA1 epitopes. This data was supported by the observations that all the sera immunoprecipitated the C-terminal +FYVE (EEA1 1064-1411) construct, a peptide that also contained the linear epitopes 1096-1140. The limited epitope mapping studies suggest that the sera from patients with non-neurological diseases recognized epitopes in the central and C-terminal EEA1 domains, whereas the patients with neurological disease recognized a more restricted set of epitopes in the C-terminal.
Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, T2N 4N1 Alberta, Canada.
Sanja
S
Selak
Michael
M
Mahler
Kiyomitsu
K
Miyachi
Mark L
ML
Fritzler
Marvin J
MJ
Fritzler
D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000276:immunology; D001327:Autoimmune Diseases / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D003001:Cloning, Molecular; D018604:Epitope Mapping; D018985:Epitopes, B-Lymphocyte / Q000276:immunology*; D005260:Female; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology; D008297:Male; D008565:Membrane Proteins / Q000276:immunology*; D008875:Middle Aged; D009422:Nervous System Diseases / Q000276:immunology*; D010446:Peptide Fragments / Q000276:immunology; D011233:Precipitin Tests; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D033921:Vesicular Transport Proteins; D016335:Zinc Fingers / Q000276:immunology
D001323:Autoantibodies; D018985:Epitopes, B-Lymphocyte; D008565:Membrane Proteins; D010446:Peptide Fragments; D011994:Recombinant Proteins; D033921:Vesicular Transport Proteins; C093846:early endosome antigen 1