Impaired interleukin-10 signaling and ovarian cancer growth in the peritoneal cavity.

e22094 Background: A spontaneous immune response to ovarian cancer improves survival, but tolerant features of the peritoneal (IP) cavity contribute to local immune suppression and tumor immune escape. Interleukin-10 (IL10) is produced by intestinal regulatory T cells (Treg) and peritoneal B1 cells, and is responsible for non-specific suppression of Th1 responses. Ovarian cancer cells also produce IL10, and high IL10 levels in ascites have been associated with a poor prognosis. We hypothesize that IL10 blockade will enhance cytotoxic T cell function in the peritoneal cavity and restrict tumor spread. Methods: We compared peritoneal T cell populations and ovarian cancer growth in IL10 knockout (IL10KO) mice and wild type controls inoculated IP with 5x10^6 ID8 ovarian tumor cells. Mice were euthanized after 9 weeks, and both ascites volume and tumor burden were quantified. Peritoneal leukocytes and splenocytes were harvested and subjected to flow cytometric analysis. Results: The average weight of the anima...