Inflammasome Induction And Immunostimulatory Effects Of Cpg-Odn Loaded Liposomes Containing Dc-Cholesterol

Objectives: This study aims to investigate the effects of cholesterol content and cationic property of liposomes on immune response.Materials and methods: Liposomes containing high amounts of 3 beta-[N-(N', N'-dimethylaminoethane)carbamoyl] cholesterol hydrochloride (DC-cholesterol) were prepared and loaded with K-and D-type CpG oligonucleotide (CpG-ODN) via dehydration-rehydration (DRV) method. After splenocytes and peritoneal exudate cells (PECs) primed with lipopolysaccharide (LPS) was incubated either with free or liposomal CpG-ODN counterparts, supernatants were collected and used in cytokine (IFN-gamma, IL-12 and IL-1 beta) ELISA. Additionally, supernatants of PECs primed with LPS and stimulated with liposomes containing different doses of DC-cholesterol were collected and used in IL-1 beta ELISA assay.Results: Low-dose CpG-ODN loaded liposomal formulations induced higher immune activation than free CpG-ODN at the same dose. While high-dose liposomal CpG-ODN formulations decreased pro-inflammatory cytokine production in splenocytes, they increased the secretion of IL-1 beta. Inflammasome activation was increased in a dose dependent manner when PECs primed with LPS were incubated with only liposomes. Varying lipid molar ratios of DC-Cholesterol containing liposomes increased IL-1 beta production based on increasing lipid molar ratio.Conclusion: This study revealed that type and lipid ratio of liposomes may alter the cellular efficacy of the loaded immune-stimulatory agent and may initiate inflammasome activation.