Poster Presentation The 13th International Congress of the Immunology of Diabetes Society 2013

A Novel Hydrogel Microparticle Matrix to Deliver Autoantigen and Adjuvant utilizing the NOD mouse to prevent Type 1 Diabetes. (#201)

Young-Mee Yoon 1 , Clive Wasserfall 1 , Jamal Lewis 1 , Mark Atkinson 1 , Benjamin Keselowsky 1
  1. University of Florida, Gainesville, FL, United States

Autoantigen specific tolerance is preferable to global immunosuppression in the treatment of the autoimmune disease Type 1 Diabetes. To that end we used as adjuvants CpG and hemoglobin:haptoglobin (Hb:Hp) complexes delivered in a hydrogel along with microparticles (MP) containing denatured insulin (25.8mg insulin/mg MP, 5mg MP/injection). Five groups of NOD females (n=10 each starting at 8 weeks of age) were treated by subcutaneous injection of; 1) empty hydrogel/empty MP, 2) soluble CpG/Hb:Hp and insulin without matrix, 3) CpG/Hb:Hp in the hydrogel along with insulin MP (3 injections two weeks apart),  4) CpG/Hb:Hp with insulin MP with two additional injections 3 weeks apart and 5) a no treatment control. Blood glucose (BG) levels were monitored once per week from 10 weeks of age until study endpoint at 28 weeks of age. Diabetes was defined as BG > 250mg/dL on two consecutive days. The no treatment, empty gel/ empty MP and  soluble CpG/Hb:Hp/insulin groups all had 10-20% diabetes free survival at end point, while the 3 injection and 5 injection group with the full adjuvant and insulin matrix were at 50 and 80% diabetes free survival respectively. (p<0.0114, Kaplan Meier). The matrix formulations with insulin caused a granuloma with infiltration of T, B and macrophage populations that also stained for LYVE indicating a tertiary lymphoid organ. While the 3 injection group granulomas resolved, the group with 5 injections still had evidence of this feature at end point. These results demonstrate the feasibility of delivering autoantigen with various adjuvant combinations in a dose low enough that when given without a matrix no efficacy was observed while delivering the entire formulation within the hydrogel/MP matrix up to 80% prevention of Type 1 Diabetes was obtained. Future directions include optimizing the formulations and timing of vaccine delivery in order to move toward clinical translation.