Lipid C2 is an ionizable cationic lipid utilized in the formation of lipid nanoparticles (LNP) for the delivery of mRNA in vivo. LNPs containing Lipid C2 and encapsulating mRNA reporter genes specifically accumulate in the liver and spleen of mice, while avoiding the heart, lungs, and kidneys. Additionally, LNPs with Lipid C2 that encapsulate mRNA encoding Epstein-Barr virus (EBV) protein Latent Membrane Protein 2 (LMP-2), when combined with anti-programmed cell death protein 1 (PD-1) antibodies, have been shown to reduce tumor size, reverse T cell exhaustion, increase the percentage of CD3+CD8+ central T cells and CD3+CD8+ effector memory T cells in the spleen, and decrease the percentage of CD3+T cells expressing Pd-1 in a CT26 mouse model of EBV-infected colon cancer.