Gene Therapy with an Adeno-Associated Viral Vector Expressing Human Interleukin-2 Alters Immune System Homeostasis in Humanized Mice

Recombinant adeno-associated viruses (rAAVs) serve as vectors for in vivo gene delivery in both mice and humans, and have broad applicability for the treatment of genetic diseases. Clinical trials with AAV vectors have demonstrated promise and safety in several human diseases. However, the in vivo validation of novel AAV constructs expressing products that act specifically on human cells and tissues is limited by a paucity of effective translatable models. Humanized mice that are engrafted with human cells, tissues, and immune systems offer strong potential to test the biological effectiveness of AAV vectors on human cells and tissues. Using the BLT (bone marrow, liver, thymus) humanized NOD-scid Il2rgnull (NSG) mouse model, which enables efficient development of HLA-restricted effector and regulatory T cells (Tregs), we have evaluated the delivery and function of human interleukin (IL)-2 by an AAV vector. Humanized mice treated with an AAV vector expressing human IL-2 showed a significant and sustained i...