Thyroid microsomal/thyroid peroxidase autoantibodies show discrete patterns of cross-reactivity to myeloperoxidase, lactoperoxidase and horseradish peroxidase.
The recent cloning of the thyroid peroxidase (TPO) has shown that it is identical to the thyroid microsomal antigen (TMA), a potent antigen involved in autoimmune thyroid disease (ATD), which shares significant sequence homology with myeloperoxidase. The present study shows that autoantibodies (aAb) to the TMA/TPO antigen cross-react with human leucocyte myeloperoxidase, bovine lactoperoxidase and horseradish peroxidase. Cross-reactivity to myeloperoxidase was only apparent by ELISA using reduced and alkylated antigen preparations or by immunoblotting following denaturation with SDS. Sequential absorption of sera on SDS-denatured thyroid microsomes immobilized on Sepharose-4B followed by absorption on native microsomes removed all aAb specificities to TMA/TPO and the three peroxidase preparations, giving compelling evidence on the genuine cross-reactive nature of these aAbs. Sera from different patients contain different qualitative and quantitative specificities of aAb to the TMA/TPO antigen, confirming the polyclonal nature of this autoimmune response.
Banga
J P
JP
Department of Medicine, King's College School of Medicine & Dentistry, London.
Tomlinson
R W
RW
Doble
N
N
Odell
E
E
McGregor
A M
AM
D000042:Absorption; D001323:Autoantibodies / Q000276:immunology*; D001666:Binding Sites, Antibody; D003429:Cross Reactions; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006735:Horseradish Peroxidase / Q000276:immunology; D006801:Humans; D015151:Immunoblotting; D007453:Iodide Peroxidase / Q000276:immunology*; D007784:Lactoperoxidase / Q000276:immunology; D008861:Microsomes / Q000276:immunology*; D009195:Peroxidase / Q000276:immunology; D012967:Sodium Dodecyl Sulfate; D013967:Thyroiditis, Autoimmune / Q000276:immunology*
D001323:Autoantibodies; C056626:thyroid microsomal antibodies; D012967:Sodium Dodecyl Sulfate; D006735:Horseradish Peroxidase; D007784:Lactoperoxidase; D009195:Peroxidase; D007453:Iodide Peroxidase