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Rapid advances in our understanding of the immune network have led to treatment modalities for malignancies and autoimmune diseases based on modulation of the immune response. Yet therapeutic modulation has resulted in immune dysregulation and opportunistic autoimmune sequelae, despite prescreening efforts in clinical trials. This review focuses on recent clinical data on opportunistic autoimmune disorders arising from three immunotherapeutic modalities: (1) systemic immunomodulators, including interferon-alpha (also used to treat hepatitis C patients) and interferon-beta; (2) monoclonal antibodies to CTLA-4 and CD52, and (3) hematopoietic stem cell transplantation. Uncategorized predisposing factors in these patients include major histocompatibility complex and gender genetics, prevalence of different autoimmune diseases, prior chemotherapy, underlying disorder (e.g., hepatitis C), and preconditioning regimens as part of organ and stem cell transplants. Not unexpectedly, the prevalent autoimmune thyroid disease surfaced frequently. Our combination models to study the balance between thyroid autoimmunity and tumor immunity upon regulatory T-cell perturbation are briefly described.

Our goal has been to develop ways to tolerize the mature immune system to any defined antigen. In this report we show that peripheral (post-thymic) T cells of mice can become tolerant to a range of antigens (human and rat immunoglobulins, and bone marrow and skin grafts that differ at multiple minor transplantation antigens). In the case of human gamma globulin (HGG), this required that the antigen be given under the cover of a short course of non-depleting anti-CD4 antibody, while for tolerance to skin and marrow grafts anti-CD8 antibody was also required. Tolerance to HGG could be reinforced by repeated injections of HGG, but was lost in the absence of any further exposure to antigen. This reversal of tolerance with time was due to new T cells being exported from the thymus, as it was not observed in tolerized, adult thymectomized mice. In contrast, tolerance to marrow and skin grafts was permanent, presumably because the established grafts acted as a continuous source of antigen to reinforce the tolerant state. Tolerance could not be broken by the infusion of unprimed spleen cells and in one example (tolerance to Mls-1a) there was clear evidence that specific peripheral T cells were anergic. We propose that anergic cells may themselves participate in reinforcing the tolerant state by competing at sites of antigen presentation.

SUMMARY The in vitro proliferative response of T cells primed with human thyroglobulin (Tg) was compared in 11 independent haplotypes on B10 background. B10.K and B10.S mice were the most responsive, whereas, with the exception of B10.PL (H-2u, all other B10 congenics were intermediate responders. The two best responders to in vitro challenge with human Tg, of the k and s haplotype, are the same as those showing H-2-linked susceptibility to induction of experimental autoimmune thyroiditis (EAT) with mouse Tg. Since shared epitopes on human and mouse Tgs have been shown to be thyroiditogenic by adoptive transfer studies in CBA (H-2k) mice, the findings indicate that shared epitopes may be studied in appropriate (i.e. EAT-susceptible) strains of mice. Therefore, we proceeded to develop methods to produce T-cell lines and hybridomas to human Tg in B10.K and B10.S mice, test their cross-reactivity to heterologous Tgs and their Ia restriction patterns. By using antigen-presenting cells from recombinant strains, we identified restriction elements encoded by the I-A subregion alone and a combinatorial molecule from the I-AI/I-E subregions.

Experimental autoimmune thyroiditis (EAT) in mice is an excellent model for Hashimoto's thyroiditis (HT). It is induced with thyroglobulin (Tg), a known thyroid autoantigen that is common to both mouse and human and for which several conserved, thyroiditogenic epitopes have been identified. This unit describes induction and evaluation of EAT using thyroid histology and in vitro proliferative response assays. An ELISA is presented to detect the level of antibody to mouse thyroglobulin (MTg). To induce EAT, either bacterial lipopolysaccharide (LPS) or supplemented complete Freund's adjuvant (CFA) can be used as adjuvant. A support protocol for preparing MTg is included. The T cell proliferation assay can be used to examine the antigenicity of synthetic peptides derived from MTg or heterologous Tg. EAT can be adoptively transferred utilizing cells that have been expanded in vitro, as described. A protocol is provided for inducing tolerance using deaggregated MTg; induction of tolerance requires larger amounts of MTg but efficiently suppresses EAT development. Also included is a protocol to demonstrate the role of regulatory T cells in mediating tolerance. A protocol to delineate HLA association with HT is illustrated using HLA class II transgenic mice. Curr. Protoc. Immunol. 78:15.7.1-15.7.21. © 2007 by John Wiley & Sons, Inc. Keywords: autoimmune thyroiditis; experimental autoimmune thyroiditis; EAT; HLA class II transgenes; HLA-DR3 association; regulatory T cells in EAT

Mouse thyroglobulin (MTg) or thyroid extract (TE) was given repeatedly to good responder C3H/Anf (H-2k) and poor responder BALB/c (H-2d) mice in the absence of adjuvant. Anti-MTg antibodies reached high levels in good responder mice given high doses of thyroid antigen. To eliminate stimulation by alloantigenic determinants and reduce the chance of denaturation. TE from syngeneic mice was prepared freshly each week and injected into good and poor responder strains. Again, significant antibody titers were observed in good responder mice. The antibody was specific for MTg since (a) it was not inhibited by extracts of other organs and (b) it reacted strongly with the closely related rat Tg and weakly with Tg from other species. Histology revealed mononuclear cell infiltration of the thyroid of good responder, but not of poor responder mice, regardless of the strain used to provide the thyroid antigen. The data demonstrate the presence of both T and B cell populations reactive with this self antigen and their stimulation by repeated high doses of antigen, without the aid of adjuvant, to override the regulatory controls that normally prevent autoimmune responses.