Superiority of thyroid peroxidase DNA over protein immunization in replicating human thyroid autoimmunity in HLA-DRB1*0301 (DR3) transgenic mice

Abstract

SUMMARYMurine experimental autoimmune thyroiditis (EAT), characterized by thyroid destruction after immunization with thyroglobulin (Tg), has long been a useful model of organ-specific autoimmune disease. More recently, porcine thyroid peroxidase (pTPO) has also been shown to induce thyroiditis, but these results have not been confirmed. When (C57BL/6 ¥ CBA) F 1 mice, recently shown to be susceptible to mouse TPO-induced EAT, were immunized with plasmid DNA to human TPO (hTPO) and cytokines IL-12 or GM-CSF, significant antibody (Ab) titres were generated, but minimal thyroiditis was detected in one mouse only from the TPO + GM-CSF immunized group. However, after TPO DNA immunization of HLA-DR3 transgenic class II-deficient NOD mice, thyroiditis was present in 23% of mice injected with TPO + IL-12 or GM-CSF. We also used another marker for assessing the closeness of the model to human thyroid autoimmunity by examining the epitope profile of the anti-TPO Abs to immunodominant determinants on TPO. Remarkably, the majority of the anti-TPO Abs was directed to immunodominant regions A and B, demonstrating the close replication of the model to human autoimmunity. TPO protein immunizations of HLA-DR3 transgenic mice with recombinant hTPO did not result in thyroiditis, nor did immunization of other mice expressing HLA class II transgenes HLA-DR4 or HLA-DQ8, with differential susceptibility to Tg-induced EAT. Moreover, our efforts to duplicate exactly the experimental procedures used with pTPO also failed to induce thyroiditis. The success of hTPO plasmid DNA immunization of DR3 + mice, similar to our reports on Tg-induced thyroiditis and thyrotropin receptor DNA-induced Graves' hyperthyroidism, underscores the importance of DR3 genes for all three major thyroid antigens, and provides another humanized model to study autoimmune thyroid disease.

cDNA Immunization of Mice with Human Thyroglobulin Generates Both Humoral and T Cell Responses: A Novel Model of Thyroid Autoimmunity

“…For example, the administration of TPO in a plasmid format, resulted in high affinity antibodies with limited epitopic recognition, similar to the TPO antibodies produced in HT patients [54] . Subsequent manipulation of this protocol produced lymphocytic infiltration in DR3+ MHCII-null/NOD mice, creating an even more accurate model of disease [55] . Finally, the EAGD model, in which TSHR cDNA is administered in an adenoviral vector, produces TSHR stimulating antibodies and hyperthyroidism [43] .…”

New approaches for predicting T cell–mediated drug reactions: A role for inducible and potentially preventable autoimmunity

“…HLA alleles are associated with multiple autoimmune diseases. For example, SLE (51), Adison’s disease (52), Graves’ disease 163 (53), and celiac disease (54) were associated with HLA-DR3. Autoimmune diseases can occur concomitantly in the same patient in a number of cases; for example, diabetes mellitus is present in 11.6% of SLE patients (55).…”