LCVM infection generates tumor antigen-specific immunity and inhibits growth of nonviral tumors

Antibodies and T cells specific for tumor-associated antigens (TAA) are found in individuals without cancer but with a history of infections and are associated with lowered cancer risk. We hypothesized that those immune responses were generated to transiently abnormally expressed self-antigens on infected cells (disease-associated antigens, DAA) and later on tumor cells as TAA. We tested this hypothesis in mice with a history of infection with lymphocytic choriomeningitis virus (LCMV) Armstrong strain (Arm) that causes acute infection when injected intraperitoneally or CL-13 strain that establishes chronic infection when injected intravenously. Both elicited antibodies and T cells that recognized DAA/TAA on infected cells and on mouse tumors. When challenged with those tumors, Arm-experienced mice controlled tumors better than CL-13-experienced mice or infection-naïve mice. We characterized 7 DAA/TAA that were targets of LCMV-elicited antitumor immunity. We then vaccinated mice with tumor-derived gp96, a heat shock protein that binds a variety of TAA peptides, including those expressed on virus-infected cells as DAA. Tumor-gp96 vaccine induced DAA/TAA-specific immunity. When challenged with Cl-13, the mice showed lower viral copy numbers both early (day 7) and late (day 70) in infection. DAA/TAA may be immunogenic and safe candidates to develop vaccines to control both infections and cancer.