Browsing by Subject "CpG oligodeoxynucleotide"
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Item Open Access Enhanced immunostimulatory activity of cyclic dinucleotides on mouse cells when complexed with a cell-penetrating peptide or combined with CpG(Wiley - V C H Verlag GmbH & Co. KGaA, 2015) Yildiz, S.; Alpdundar, E.; Gungor, B.; Kahraman, T.; Bayyurt, B.; Gursel, I.; Gursel, M.Recognition of pathogen-derived nucleic acids by immune cells is critical for the activation of protective innate immune responses. Bacterial cyclic dinucleotides (CDNs) are small nucleic acids that are directly recognized by the cytosolic DNA sensor STING (stimulator of IFN genes), initiating a response characterized by proinflammatory cytokine and type I IFN production. Strategies to improve the immune stimulatory activities of CDNs can further their potential for clinical development. Here, we demonstrate that a simple complex of cylic-di-GMP with a cell-penetrating peptide enhances both cellular delivery and biological activity of the cyclic-di-GMP in murine splenocytes. Furthermore, our findings establish that activation of the TLR-dependent and TLR-independent DNA recognition pathways through combined use of CpG oligonucleotide (ODN) and CDN results in synergistic activity, augmenting cytokine production (IFN-α/β, IL-6, TNF-α, IP-10), costimulatory molecule upregulation (MHC class II, CD86), and antigen-specific humoral and cellular immunity. Results presented herein indicate that 3′3′-cGAMP, a recently identified bacterial CDN, is a superior stimulator of IFN genes ligand than cyclic-di-GMP in human PBMCs. Collectively, these findings suggest that the immune-stimulatory properties of CDNs can be augmented through peptide complexation or synergistic use with CpG oligonucleotide and may be of interest for the development of CDN-based immunotherapeutic agents.Item Open Access Inflammasome induction and immunostimulatory effects of CpG-ODN loaded liposomes containing DC-cholesterol(Turkish Society of Immunology, 2013) Bayyurt, B.; Gürsel I.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 3β-[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-g, IL-1γ and IL-1β) ELISA. Additionally, supernatants of PECs primed with LPS and stimulated with liposomes containing different doses of DC-cholesterol were collected and used in IL-1β 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-1β. 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-1β 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. © 2014 Turkish Journal of Immunology.Item Open Access Structure, mechanism and therapeutic utility of immunosuppressive oligonucleotides(Academic Press, 2016) Bayik D.; Gursel, I.; Klinman, D. M.Synthetic oligodeoxynucleotides that can down-regulate cellular elements of the immune system have been developed and are being widely studied in preclinical models. These agents vary in sequence, mechanism of action, and cellular target(s) but share the ability to suppress a plethora of inflammatory responses. This work reviews the types of immunosuppressive oligodeoxynucleotide (Sup ODN) and compares their therapeutic activity against diseases characterized by pathologic levels of immune stimulation ranging from autoimmunity to septic shock to cancer (see graphical abstract). The mechanism(s) underlying the efficacy of Sup ODN and the influence size, sequence and nucleotide backbone on function are considered. © Published by Elsevier Ltd.