Human thyroid xenografts from 7 patients with Hashimoto's
thyroiditis (HT) and 3 normal persons (N) were xenografted into severe combined immunodeficient (SCID) mice to study the intrathyroidal lymphocytes that were expected to survive in these animals. Human
IgG was detected in all mice engrafted with HT thyroid tissue peaking at 6-10 weeks after
xenografting. Thyroperoxidase-antibody (TPO-Ab) was also detected in all mice with HT thyroid grafts peaking at 4-6 weeks after
xenografting, reaching up to 44% of donors' original concentrations. In contrast, maximal
thyroglobulin (Tg)-Ab production in some SCID mice with HT thyroid grafts was higher than the donors' original level, and was detectable in mice with thyroid grafts from Tg-Ab-negative HT donors.
Thyroid stimulation-blocking antibody (
TSBAb) was found in 2 mice with thyroid xenografts from 1 HT patient whose original serum
TSBAb and
thyrotropin-binding inhibitor
immunoglobulin (TBII) had been positive; the maximal
TSBAb level in SCID mice exceeded the donor's original level.
TSBAb production in SCID mice reached its peak
at 10 weeks after
xenografting, i.e., later than that of
thyroid-stimulating antibody (TSAb) observed in our recent report, suggesting the existence of distinct intrathyroidal B cell autoreactive clones of different life span responsible for secreting TSAb or
TSBAb. When autologous peripheral blood mononuclear cells (PBMC) were engrafted alone (without thyroid tissue),
TSBAb was undetectable.(ABSTRACT TRUNCATED AT 250 WORDS)