Identification of histidine-rich glycoprotein, a potential autoantigen, in human and rat brain preparations.
Beta(2)-glycoprotein-I (beta(2)-GPI, also known as apolipoprotein H) is a major autoantigen in the antiphospholipid syndrome (APS), a disease commonly affecting the central nervous system. We examined whether beta2-GPI and similar proteins exist in rat and human brains. No expression was found on Northern blot analysis of human brain. Utilizing a standard procedure for the isolation of serum beta2-GPI we purified a 100 kD human brain protein, which was found by peptide sequencing to have full homology with the serum protein, histidine-rich glycoprotein (HRGP). Expression of HRGP in rat and human brain was established by RT-PCR studies and a partial sequence of rat brain HRGP was obtained showing 68% homology with the human protein. IgG from most APS patients bound to HRGP, which shares distinct biochemical properties with beta2-GPI, is present in the brain and may be an important autoantigen.
Ball-Rosen
Catrin
C
Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv 69978, Israel.
Primak-Rubinovicz
Hagit
H
Korczyn
Amos D
AD
Wang
Ningshan
N
Farchi
Adel
A
Shavit
Sara
S
Shoenfeld
Yehuda
Y
Chapman
Joab
J
D000818:Animals; D016736:Antiphospholipid Syndrome / Q000276:immunology / Q000378:metabolism; D001324:Autoantigens / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism*; D001921:Brain / Q000276:immunology / Q000378:metabolism*; D006023:Glycoproteins / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism*; D006801:Humans; D011506:Proteins / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000099053:Histidine-Rich Glycoprotein