Background Graves’-like disease, reflected by thyrotropin receptor (TSHR) antibodies and hyperthyroidism
May 29, 2017
Background Graves’-like disease, reflected by thyrotropin receptor (TSHR) antibodies and hyperthyroidism in some mouse strains, can be induced by immunization with adenovirus-expressing DNA for the human TSHR or its A-subunit. histology were studied at euthanasia. Results The majority of WT mice retained high TSHR antibody levels measured by TBI or ELISA at euthanasia but only about 50% were TSAb positive. Low-expressor tgs exhibited self-tolerance, with fewer mice positive by TBI or ELISA and antibody levels were lower than in WT littermates. In WT mice, antibody persistence was similar after two or three immunizations; for tgs, only mice immunized three times had detectable TSAb at 20 weeks. Unlike our previous observations of hyperthyroidism in WT mice examined 4 or 10 weeks after immunization, all mice were euthyroid at 20 weeks. Conclusions Our findings for Epothilone D induced TSHR antibodies in mice, similar to data for human thyroid autoantibodies, indicate that the parameters that contribute to the concentration of the antibody and thereby play a critical role in long-term persistence of TSHR antibodies are the degree of self-tolerance to the TSHR and chronic stimulation. Introduction Mouse models of induced Graves’ disease require expression of the thyrotropin receptor (TSHR) or its A-subunit by injecting TSHR-expressing cells or immunization with plasmid or adenoviral vectors encoding TSHR DNA [reviewed in Nagayama (1)]. The Nagayama model involves repeated intramuscular shot of adenovirus expressing the human being TSHR (2). Following investigations had been performed to optimize induction of Graves’-like disease (shown by TSHR antibodies and hyperthyroidism in a few mouse strains) by tests the efficacy from the A-subunit versus the full-length TSHR, evaluating low versus high adenovirus dosage, and injecting dendritic cells expressing the A-subunit [evaluated in Nagayama (1)]. Nevertheless, none of them of the scholarly research transformed the timing from the process, namely, three shots of adenovirus or cells at 3-week intervals and euthanasia four weeks following the third shot. In addition, until recently, no studies were directed at determining the long-term persistence of adenovirus-induced TSHR antibodies. It should be emphasized that both the adenovirus and the immune system can contribute to long-term responses against the TSHR. First, the protein encoded by the adenovirus continues to be expressed for some time after a single injection and is, therefore, available for antigen uptake and presentation to the immune system. In developing the adenovirus model, Nagayama and colleagues confirmed TSHR expression by demonstrating Epothilone D radiolabeled TSH binding to muscle preparations from mice injected 5 days previously (2). Further, expression of a herpes Epothilone D simplex virus type 1 thymidine kinase persisted for 3 months in the pituitary of mice injected once with adenovirus encoding the thymidine kinase (3). Second, IgG class antibodies have relatively long half-lives, up to 8 days depending on the subclass (4,5). Third and even more important, plasma cells persist long term (months rather than weeks) and continue to secrete antibody Rabbit Polyclonal to MRPL11. independently of antigenic stimulation (6,7). Against this background, we investigated the long-term (up to 20 weeks) persistence of TSHR antibodies in BALB/c mice immunized twice or three times with human A-subunit-adenovirus (A-sub-Ad). While our investigation was in progress, two publications provided information on the same topic (8,9). As will be discussed later, the focus of these two studies differed from each other as well as from the current investigation. In addition to wild-type (WT) mice, our study was performed in transgenic (tg) mice that exhibit self-tolerance to the immunogen because they express the human TSHR A-subunit in the thyroid. Our findings provide insight into the parameters that contribute to the concentration of the antibody and thereby play a crucial part in long-term persistence of TSHR antibodies, specifically, the amount of self-tolerance towards the TSHR and chronic excitement. Strategies Mice and TSHR A-sub-Ad immunization We researched tg mice that communicate low intrathyroidal degrees of the human being TSHR A-subunit (Lo-tgs) (10) and WT littermates. Characterization and Era of tg mice using the human being TSHR A-subunit targeted.