Adoptive Transfer of Antithyrotropin Receptor (TSHR) Autoimmunity from TSHR Knockout Mice to Athymic Nude Mice

Abstract

We have recently shown that wild type mice are highly tolerant, whereas thyrotropin receptor (TSHR) knockout (KO) mice are susceptible to immunization with the mouse TSHR, the autoantigen in Graves' disease. However, because TSHR KO mice lack the endogenous TSHR, Graves-like hyperthyroidism cannot be expected to occur in these mice. We therefore performed adoptive transfer of splenocytes from TSHR KO mice into nude mice expressing the endogenous TSHR. Anti-TSHR autoantibodies were detected in approximately 50 % recipient mice 4 wk after adoptive transfer of splenocytes (5 × 10⁷/mouse) from TSHR KO mice immunized with adenovirus expressing mTSHR A subunit and persisted for 24 wk. Depletion of regulatory T cells by anti-CD25 antibody in the donor mice increased successful transfer rates without increasing antibody levels. Some recipient mice showed transient increases in thyroid-stimulating antibodies and T₄ levels 4-8 wk after transfer, but many became thyroid-blocking antibody positive and hypothyroid 24 wk later. Adoptive transfer of splenocytes from naïve TSHR KO mice transiently induced very low antibody titers when the recipient mice were treated with anticytotoxic lymphocyte antigen 4 and antiprogrammed cell death 1 ligand 1 antibodies for 8 wk after transfer. Histologically, macrophages infiltrated the retrobulbar adipose tissues and extraocular muscles in a small fraction of the recipients. Our findings demonstrate successful adoptive transfer of anti-TSHR immune response from TSHR KO mice to nude mice. Although the recipient mice developed only transient and infrequent hyperthyroidism, followed by eventual hypothyroidism, induction of orbital inflammation suggests the possible role of anti-TSHR immune response for Graves' orbitopathy.

Cutting Edge: Retrobulbar Inflammation, Adipogenesis, and Acute Orbital Congestion in a Preclinical Female Mouse Model of Graves' Orbitopathy Induced by Thyrotropin Receptor Plasmid-in Vivo Electroporation

“…Although TSAbs and serum T 4 were transiently elevated in some animals, over time the antibodies switched to TSBAbs with consequent hypothyroidism. Notably, weak signs of orbital inflammation were manifest in a few animals (24). Thus, switching of the anti-TSHR response from TSAbs to TSBAbs (24,25), or the dominant presence of TSBAbs and ensuring hypothyroidism during the course of autoimmunity as reported in this study, may be important contributory factors for onset of GO.…”

“…It can be postulated that these differences in the anti-TSHR response may contribute to the pathologic outcome in the 2 models. Recent findings from Nakahara and colleagues (24) provide some supportive evidence, in which they have expanded their studies by developing a unique authentic model of GD. The group used adenovirus coding for mouse (m) TSHR A-subunit for immunization of TSHR knockout mice, followed by adoptive transfer into immunodeficient mice (24).…”

“…Recent findings from Nakahara and colleagues (24) provide some supportive evidence, in which they have expanded their studies by developing a unique authentic model of GD. The group used adenovirus coding for mouse (m) TSHR A-subunit for immunization of TSHR knockout mice, followed by adoptive transfer into immunodeficient mice (24). Although TSAbs and serum T 4 were transiently elevated in some animals, over time the antibodies switched to TSBAbs with consequent hypothyroidism.…”

Thyrotropin-Blocking Autoantibodies and Thyroid-Stimulating Autoantibodies: Potential Mechanisms Involved in the Pendulum Swinging from Hypothyroidism to Hyperthyroidism or Vice Versa

“…First, TSHR knockout mice (which lack tolerance to the mouse TSHR) develop TSHR antibodies when immunized with adenovirus expressing the mouse TSHR A-subunit (56). Second, primed immune cells from these animals are adoptively transferred to athymic mice to determine their effect on thyroid function (57). The transferred immune cells do not reconstitute the defective immune system of athymic mice but instead generate TSHR antibodies for extended time periods.…”

“…The transferred immune cells do not reconstitute the defective immune system of athymic mice but instead generate TSHR antibodies for extended time periods. In the recipient mice, both TSAb and TBAb activity are detectable 4-8 weeks after transfer but after 24 weeks, TSAb activity and hyperthyroidism switch to TBAb activity and hypothyroidism (57).…”