Figure 1. Proposed model of immune response after vaccination with peptide/IFA + covax vs. peptide/saline + covax. Vaccination with peptide in IFA + covax (top) results in a persistent, antigen-rich vaccine depot that primes T cells to become effector cells that enter the circulation. Effector T cells reaching vaccination sites encounter high densities of peptide antigen (high [Ag]), prompting high IFN-γ release, inflammation and chemokine production and stronger T-cell accumulation than comparatively low [Ag] tumors. Eventually, most T cells at vaccination sites are deleted while remaining T cells are dysfunctional and poorly control tumor growth. Vaccination with peptide in saline + covax (bottom) also primes T cells, but vaccine antigen is cleared rapidly, resulting in T-cell accumulation at the most antigen-dense remaining site (tumor). Remaining memory cells are functional to control recurrence and respond to booster vaccination.