IMMU-33. CCL4 DRIVES GLIOBLASTOMA (GBM) TUMOR MICROENVIRONMENT (TME) REPROGRAMMING AFTER TREATMENT WITH A NOVEL MRNA VACCINE

Abstract INTRODUCTION Our group has developed a patented vaccine platform that combines an mRNA-nanoparticle with CXCL9 loaded polyethylene glycol (PEG) hydrogel. The HCM is given SQ and recruits diverse immune cell population to deliver large payload of mRNA. objective these studies was evaluate the effects vaccination on TME. METHODS C57BL/6 mice underwent intracranial implantation KR158 or GL261 glioma cells. formulated total tumor mRNA, DOTAP, PEG hydrogel created in collaboration College Engineering. Survival were analyzed Mantel-Cox test. Flow cytometry ELISA data using ANOVA. Graphpad used for statistical analysis. RESULTS Intracranial bearing treated injection (total CXCL9, hydrogel). delivery resulted significant survival benefit whereas did not (p = 0.0012). In separate experiment, tumors spleens collected flow cytometry. A increase antigen specific CD8 T cells found. Separately, after vaccination, PCR Tumors demonstrated upregulation CCL4 CXCR6. without blockade CCL4. no vaccine. CONCLUSION results migration within TME increases efficacy dependent