biostudies-literatureMurphy BNational Institute of Neurological Disorders and StrokeNational Institute of Allergy and Infectious DiseasesNIAID NIH HHSW.W. Smith Charitable TrustNational Cancer InstituteNINDS NIH HHSNCI NIH HHSNational Institutes of HealthDepartment of DefenseNIH HHSJapan Society for the Promotion of Sciencee20231967https://www.ebi.ac.uk/biostudies/studies/S-EPMC11586802biostudies-literatureUnknown221(12)Patients with metastatic ovarian cancer (OvCa) have a 5-year survival rate of <30% due to the persisting dissemination of chemoresistant cells in the peritoneal fluid and the immunosuppressive microenvironment in the peritoneal cavity. Here, we report that intraperitoneal administration of β-glucan and IFNγ (BI) induced robust tumor regression in clinically relevant models of metastatic OvCa. BI induced tumor regression by controlling fluid tumor burden and activating localized antitumor immunity. β-glucan alone cleared ascites and eliminated fluid tumor cells by inducing intraperitoneal clotting in the fluid and Dectin-1-Syk-dependent NETosis in the omentum. In omentum tumors, BI expanded a novel subset of immunostimulatory IL27+ macrophages and neutralizing IL27 impaired BI efficacy in vThe Journal of experimental medicineMyeloid activation clears ascites and reveals IL27-dependent regression of metastatic ovarian cancer.PMC11586802R50 CA211199P30 CA010815202360517P50 CA228991S10 OD0302441R37CA280869C2205R21 CA259240P50CA228991K99 AI151198R01 NS131912R37 CA280869T32 CA0091711R01NS1319121R21CA259240R21 AI175738P30CA0108155R21AI175738HT94252410206K99AI151198Nefedova YHamada KZhang NHuang LZhang RMurphy BClaiborne DTKannan TVeglia FMiyamoto TZhu YPMirji GKossenkov AUgolini AManning BSShinde RfalseMyeloid activation clears ascites and reveals IL27-dependent regression of metastatic ovarian cancer.Patients with metastatic ovarian cancer (OvCa) have a 5-year survival rate of <30% due to the persisting dissemination of chemoresistant cells in the peritoneal fluid and the immunosuppressive microenvironment in the peritoneal cavity. Here, we report that intraperitoneal administration of β-glucan and IFNγ (BI) induced robust tumor regression in clinically relevant models of metastatic OvCa. BI induced tumor regression by controlling fluid tumor burden and activating localized antitumor immunity. β-glucan alone cleared ascites and eliminated fluid tumor cells by inducing intraperitoneal clotting in the fluid and Dectin-1-Syk-dependent NETosis in the omentum. In omentum tumors, BI expanded a novel subset of immunostimulatory IL27+ macrophages and neutralizing IL27 impaired BI efficacy in v2024-01-01T00:00:00Z2024 Dec2026-06-11T05:10:31.13Z2026-06-11T03:08:06.641ZS-EPMC115868023957037410.1084/jem.20231967