Oncolytic influenza A virus expressing interleukin-15 decreases tumor growth in vivo

Background Interleukin-15 has become a promising molecule in the context of eliciting an effective, antitumor immune response because it is able to stimulate cells of the innate and adaptive immune system. Methods We generated an interleukin-15-expressing oncolytic influenza A virus for the treatment of an established murine tumor model. Results Our oncolytic influenza A virus produced large amounts of interleukin-15 and induced proliferation and activation of human T cells in vitro. Intraperitoneal administration increased the amount of mouse natural killer cells and effector memory T cells, as well as T cell reactivity in vivo. Moreover, intratumoral injection induced a profound decrease in growth of established tumors in mice and increased the amount of tumor-infiltrating T cells and natural killer cells. Conclusion We established a stable, IL-15-producing oncolytic influenza A virus with promising immunostimulatory and antitumor attributes.