CREATION OF A MOUSE MODEL OF CELIAC DISEASE BY IN VIVO LONG TERM EXPRESSION OF DISEASE SPECIFIC ANTITRANSGLUTAMINASE ANTIBODY

Abstract

Aim: The appearance of autoantibodies targeted against tissue transglutaminase (tTG) is a typical feature for Celiac Disease (CD). Several preliminary reports suggest a role of the antibody response in the disease but to establish whether and how the tTG antibodies play a role in CD pathogenesis an animal model in still lacking. We propose to achieve long-term expression of CD specific anti tTG antibodies in an animal model inorder to evaluate their biological role. Methods: Monoclonal antibody recognizing and inhibiting human and mouse tTG were isolated from an antibody library made from CD patient. These antibodies were engineered in a novel form called “miniantibody” produced by genetic fusion of human anti-tTG scFv to mouse IgG CH2-CH3 domains. This confers both effectors functions to the antibody and prevents from a rapid clearance. The gene was then cloned into an Adeno Associated Virus (AAV) expression vector for in vivo secretion of the protein. Results: Preliminary experiments in eukaryotic cell line show that the miniantibody is efficiently secreted as dimeric molecule, is correctly glicosylated and retains binding specificity and affinity of the original antibody. The AAV vector was used for in vivo experiments on C57/bl mice. 3 weeks after a single intramuscularly administration miniantibodies were present in the serum. The titer remains stable and sustained for more than 1 year. Biological parameters such as body weight, blood sugar level, lymphocyte activation, motor dysfunction, and in situ deposits were monitored. Preliminary data analysis indicates modification on some parameters like lymphocyte activation markers. Conclusion: High titre and long time expression of antibody are typical of the disease. We are now able to mimic this situation in an animal model providing long-term sustained production of anti tTG antibodies.