B cell tolerance and antibody production to the celiac disease autoantigen transglutaminase 2.
du Pré MF., Blazevski J., Dewan AE., Stamnaes J., Kanduri C., Sandve GK., Johannesen MK., Lindstad CB., Hnida K., Fugger L., Melino G., Qiao S-W., Sollid LM.
Autoantibodies to transglutaminase 2 (TG2) are hallmarks of celiac disease. To address B cell tolerance and autoantibody formation to TG2, we generated immunoglobulin knock-in (Ig KI) mice that express a prototypical celiac patient-derived anti-TG2 B cell receptor equally reactive to human and mouse TG2. We studied B cell development in the presence/absence of autoantigen by crossing the Ig KI mice to Tgm2 -/- mice. Autoreactive B cells in Tgm2 +/+ mice were indistinguishable from their naive counterparts in Tgm2 -/- mice with no signs of clonal deletion, receptor editing, or B cell anergy. The autoreactive B cells appeared ignorant to their antigen, and they produced autoantibodies when provided T cell help. The findings lend credence to a model of celiac disease where gluten-reactive T cells provide help to autoreactive TG2-specific B cells by involvement of gluten-TG2 complexes, and they outline a general mechanism of autoimmunity with autoantibodies being produced by ignorant B cells on provision of T cell help.