Increased synthetic peptide specificity of tissue-CSF bound anti-MBP in multiple sclerosis.
Free and bound hydrosoluble protein extracts were prepared from four anatomical areas of a multiple sclerosis (MS) cerebrum and from corresponding anatomical areas of a normal (non-MS) control. Increased levels of IgG and anti-myelin basic protein antibodies (anti-MBP) were detected in all MS samples and they were undetectable in the controls. IgG and anti-MBP from free (unbound) hydrosoluble protein extracts are defined as free IgG and free anti-MBP while IgG and anti-MBP from tissue bound protein extracts are defined as bound IgG and bound anti-MBP. IgG was purified from free protein extracts by protein G Sepharose affinity chromatography and anti-MBP was further isolated from purified IgG by antigen specific (MBP) Sepharose affinity chromatography. Free and bound anti-MBP were reacted with 20 synthetic peptides of human MBP prepared by the Fmoc method. Free anti-MBP, whether in the context of whole protein extracts, or as purified IgG or as purified antibody was completely neutralized by peptides #12, #15, #56 and #56* containing overall residues 75-106, partially neutralized by peptides #27, #16 and #21 containing overall residues 61-83 and did not react with the remaining 13 peptides. Tissue bound anti-MBP was completely neutralized only by peptides #12, #15, #56 and #56* (overall residues 75-106) and showed no reactivity towards the remaining 16 peptides including peptides #27, #16 and #21. Synthetic peptide specificity of free anti-MBP purified from MS cerebrum was identical to previously reported specificity of free anti-MBP from MS cerebrospinal fluid (CSF), while tissue bound anti-MBP, as well as bound anti-MBP from CSF had a more restricted synthetic peptide specificity than free anti-MBP. This suggests that the most likely epitope of anti-MBP is located between residues 84 and 95 of human MBP just proximal to the tri-proline sequence (99-101).
Warren
K G
KG
Department of Medicine (Neurology), University of Alberta, Edmonton, Canada.
Catz
I
I
D000328:Adult; D000918:Antibody Specificity; D001323:Autoantibodies / Q000032:analysis* / Q000134:cerebrospinal fluid; D001921:Brain / Q000276:immunology*; D002846:Chromatography, Affinity; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis / Q000134:cerebrospinal fluid; D008297:Male; D009103:Multiple Sclerosis / Q000276:immunology*; D004676:Myelin Basic Protein / Q000276:immunology*; D009500:Neutralization Tests; D010446:Peptide Fragments / Q000276:immunology*; D011863:Radioimmunoassay
D001323:Autoantibodies; D007074:Immunoglobulin G; D004676:Myelin Basic Protein; D010446:Peptide Fragments