<qa>  What is the IL-22 IgG2 Fc fusion protein produced in serum-The sponsor has developed F-652, a recombinant human IL-22 IgG2 Fc fusion protein produced in serum-free culture of Chinese Hamster Ovary CHO cells. F-652 is able to protect tissue from damage and enhance tissue repair during the inflammation process and infection by activation of STAT3 mediated by the interleukin-22 receptor subunit 1 IL-22R1 expressed on epithelial cells such as hepatocytes. 