Nükleik asit temelli TLR ulaklarıyla kompleks oluşturan polisakkarit nanotaşıyıcıların immünstimulan mekanizmaları ve immünöterapötik uygulamaları

Toll-like receptors (TLR) contribute to the establishment of innate and adaptive immune response by inducing proinflammatory signaling cascades leading to a Th1 dominant cytokine/chemokine production from antigen presenting cells. This lead to an enhancedT-helper and cytotoxic T-cell effector functions as well as better control of infection/inflammation and cancer. However, when these ligands are administered in vivo, endonuclease digestion and adsorption onto serum proteins hampers their human phase clinical trial performances. Modifications or formulations harboring nucleic acid ligands significantly improve immunotherapeutic potential. Less expensive and less tedious formulation strategies are preferable approaches throughout the FDA approval phases. In this thesis, we first explored the mechanism of action of a group of mushroomderived polysaccharides (PS) and both in vitro and in vivo, we demonstrated that either PS directly interact with TLR2 and initiates MyD88-mediated signaling cascade or when it reaches cytosol it induces inflammasome activation leading to IL-1ß production from immune cells. This PS recognition was not through either Dectin-1, or TLR4, nor through cytosolic sensors such as NOD1 and NOD2. Next, the most promising PS, wasnanocomplexed with TLR3, TLR7 and TLR9 ligands in a single, double or triple combinations. These nanocomplex formulations were tested immunization studies against i) a model antigen ovalbumin or ii) influenza A virus (split vaccine, SV) in mice. PS/TLR ligand nanocomplexes boosted Th1-biased antibody production. Furthermore,PS nanocomplex treatment of established EG.7-mediated T-cell thymoma model in C57BL/6 mice was sufficient to induce significant tumor growth regression as a standalone therapeutic agent. In the second part of this thesis, self-nanoparticle forming CpG ODNs were used to control HuH-7-dependent hepatocellular carcinoma xenograft in athymic mice. Our data implicated that a significant HuH-7 killing was carried out by innate phagocytic/cytotoxic cells, which in vivo led to tumor regression when a nanoparticle ODN was used as the sole therapeutic choice. In the last part, we aimed to use CpG ODN motif(s) that could control infections in chicken. Different CpG ODNs, were synthesized/characterized and optimized for chicken immune system and proposed for prophylactic use to reduce uncontrolled deaths in broiler industry.Keywords: Innate immunity, polysaccharide, nanocomplex, drug delivery system, TLR, CpG ODN, cancer immunotherapy, vaccine, adjuvant.