Molecular Cloning of a Thyroid Peroxidase cDNA Fragment Encoding Epitopes Involved in Hashimoto’s Thyroiditis [HT]
Measurement of “anti microsome” antibodies in patients with thyroid diseases is part of the routine diagnostic procedures involved in the evaluation of their status. These auto-antibodies may reach extremely high titers and are responsible for the tissue destruction observed in Hashimoto thyroiditis. Until very recently the “microsomal antigen” was defined solely as an unidentified component of thyroid microsomes, different from thyroglobulin. During the last year, strong indications have been obtained in favor of the identity between the microsomal antigen and thyroid peroxydase (TP0)(l-2). However, standard antimicrosome antibody assays still use a rather crude thyroid microsome preparation as their antigen. While it would certainly be preferable to use purified TPO in such assays, the continuous preparation of purified enzyme is time consuming and expensive. Use of the recombinant DNA methodology would obviate this difficulty and provide us with unlimited amounts of clonally pure TPO antigens involved in the auto-immune process.