Iodine content of thyroglobulin in NOD.H2h4mice developing iodine-accelerated autoimmune thyroiditis

Autor: Kolypetri, Panayota, Noel, Natasha, Carayanniotis, Karen, Carayanniotis, George
Zdroj: Hormones; April 2010, Vol. 9 Issue: 2 p151-160, 10p
Abstrakt: OBJECTIVE: In NOD.H2h4mice, high dietary iodine intake has been known to cause Iodineaccelerated Spontaneous Autoimmune Thyroiditis (ISAT) via an unknown mechanism. The aim of the study was to examine whether the NOD.H2h4genetic background predisposes to enhanced iodine organification in thyroglobulin (Tg), a target autoantigen in ISAT. DESIGN: To avoid issues associated with an ongoing anti-Tg antibody response, we assessed Tg iodination levels in iodine-fed, B-cell deficient NOD.H2h4mice. Additionally, we tested whether humoral or cellular immune responses of iodine-fed NOD.H2h4mice are preferentially directed to Tg with increased iodine content (I-Tg) or known pathogenic Tg peptides that contained iodine. RESULTS: The iodine content of Tg was not significantly different between control (9.0±2.7 I atoms per monomer) and iodine-fed mice (10.9±0.3 I atoms per monomer). Furthermore, in iodine-fed NOD.H2h4mice developing ISAT, strong but equivalent serum IgG responses were detected to both Tg or I-Tg, whereas their lymphoid cells were stimulated weakly but equally well by Tg or I-Tg in vitroand did not show reactivity against a panel of five pathogenic Tg peptides that contained iodine. CONCLUSIONS: The results suggest that development of ISAT in NOD.H2h4mice is not associated with enhanced iodine organification or differential B- or T-cell responses to iodinated determinants in Tg.
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