Browsing by Subject "poly(I:C)"

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Open Access
In vivo applications of liposomal vaccines encapsulating single or dual pathogenassociated molecular patterns
(2017-03) Bayyurt Kocabaş, Banu
Nucleic acid-based pattern recognition receptor (PRR) agonists are promising adjuvants and immunotherapeutic agents. Combination of PRR ligands potentiates immune response by providing synergistic immune activity via triggering different signaling pathways and may impact antigen dependent T-cell immune memory. However, the duration of short circulation due to nuclease attacks is hampering their clinical performance. Liposomes enable protein and nucleic acid based compounds to have high encapsulation efficiency. Herein, we aimed to develop liposomal carrier systems that co-encapsulating single TLR9 or combinations with TLR3 or STING ligands and assess their potential as adjuvants and immunostimulatory agents in in vivo applications. Liposomal dual nucleic acid formulations induced synergistic innate immune activation, enhanced cytokine production along with internalization capacity of ligands. In anti-cancer vaccine study, CpG ODN and poly(I:C) coencapsulation significantly increased OVA-specific Th1-biased immune even after eight months post-booster injection. Challenge with OVA-expressing tumor cell line, E.G7, demonstrated that mice immunized with liposomes co-encapsulating CpG ODN and poly(I:C) had significantly slower tumor progression dependent on OVAspecific cytotoxic memory T-cells. In our second in vivo application, liposomal CDN and TLR9 therapy led to 80% remission of established melanoma tumor. Increased IgG2c/IgG1 ratio in mice treated with liposomal formulations indicating the development of antigen specific Th1-biased immunity was observed. Furthermore, along with the treatment, IFN-dual ligands into liposomes enhanced the anti-tumor activity of single ligands. In the third part, immunization with CpG ODN loaded liposomal formulations together with antigens increased antigen-specific humoral response against FMDV and Helicobacter. In addition, the liposomal CpG ODN reduced bacterial gastric colonization by antigen-dependent Th1 and Th17 immune responses after helicobacter challenging.
Open Access
Investigating in vivo utilization of VLP vaccines adjuvanted with single, dual, or triple pathogen-associated molecular patterns
(2023-08) Ceylan, Yasemin
COVID-19 was first identified in Wuhan, a Chinese city, and it has been a part of our lives since late December 2019. The WHO declared this disease, caused by SARS-CoV-2, a pandemic due to its high transmission rate, a status that remained in effect until May 2023. The escalating death toll and virus spread expedited vaccine development efforts. Various platforms for vaccine development have been utilized, including inactivated virus, mRNA, and subunit vaccines. Given the virus's propensity for mutations due to its high transmission rate, the chosen platform must be easy to produce, effective, and safe for immunocompromised individuals. One such platform is virus-like particles (VLPs). VLP vaccines consist of viral proteins without genetic material and are known for their ease of production. A VLP vaccine, adjuvanted with Alum and K-type CpG ODN against SARS-CoV-2, is tested in Phase II clinical trials. In addition to CpG ODN, this study aimed to evaluate the efficacy of other adjuvants and their combinations to explore potential clinical advantages. The additional adjuvants included poly(I:C) and a member of cyclic dinucleotides, 2,3-cGAMP, which are Toll-like receptor 3 (TLR3) and STING agonists, respectively. Nine groups of male mice (C57BL/6, 6–8 weeks old) received intraperitoneal injections three times with a mixture of VLP vaccine using different combinations of adjuvants, including CpG ODN, CDN, and poly(I:C). Blood samples were collected from the tail vein two weeks after each injection. Antibody ELISA was employed to assess humoral immunity against each combination of vaccines, with plates coated using in-house recombinant 6P-Spike and commercial recombinant RBD. ELISA results indicated that VLPs combined with CpG plus poly(I:C) and VLPs combined with all three adjuvants induced high levels of total IgG against RecS. Two weeks after the third injection, the animals' spleens were isolated, and cytokine profiles were assessed through an antigen recall assay. As a result, only one group exhibited the expected cytokine profile: VLPs combined with the triple adjuvant combination. This profile demonstrated the requisite Th1-biased cytokine response necessary for vaccine development. This study suggests that the triple adjuvant combination holds promise as a vaccine adjuvant for addressing future pandemics.