Browsing by Subject "TLR ligand"

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    CpG ODN loaded exosome nanovesicles: enhanced immunostimulatory activity
    (Turkish Society of Immunology, 2012-04) Güçlüler, Gözde; Kahraman, Tamer; Gürsel, İhsan
    Exosomes are naturally occurring, membranous nanovesicles known to function as intercellular communication vectors. To explore whether these naturally occuring bilayer vesicles could be exploited as a nucleic acid delivery system we intentionally loaded exosomes with TLR9 ligands and studied their immunostimulatory properties. METHODS: Exosomes were isolated from RAW264.7 and EG-7 cell supernatants by differential centrifugation, filtration and ultracentrifugation and were loaded with CpG ODNs via dehydration-rehydration protocol. Splenocytes were stimulated and analyzed by flow cytometry for cell surface marker upregulation, intracellular cytokine production and co-stimulatory molecule upregulation. Confocal microscopy analyses were done to assess internalization properties of these nanovesciles. Cell supernatants were studied by ELISA to assess Th1 biased cytokine/chemokine secretion.
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    Enhancing preventive and therapeutic cancer vaccine efficacy through biotherapeutic ligand-associated extracellular vesicles
    (Elsevier Ltd, 2024-12) Kahraman, Tamer; Akpınar, Gözde Güçlüler; Yıldırım, Muzaffer; Larssen, Pia; Bayyurt-Kocabaş, Banu; Yağcı, Fuat Cem; Gürsel, Arda; Horuluoğlu, Begüm Han; Yazar, Volkan; Ayanoğlu, İhsan Cihan; Yıldırım, Tuğce Canavar; Evcili, İrem; Yılmaz, İsmail Cem; Eldh, Maria; Gabrielsson, Susanne; Güler, Ülkü; Salih, Bekir; Gursel, Mayda; Gürsel, İhsan
    Extracellular vesicles (EVs), secreted by almost all living cells, have gained significant attention for their role in intercellular communication and their potential as versatile carriers for biotherapeutics. However, the clinical translation of EV-based therapies faces significant challenges, primarily due to the lack of efficient methods for loading biotherapeutic agents into EVs. This study introduces a simple, reproducible strategy for the simultaneous incorporation of various biotherapeutics within EVs. The process is gentle and preserves the essential physicochemical and biological characteristics of EVs, thereby protecting labile ligands from premature degradation and elimination. The binding and uptake efficiency of EVs by target cells reached approximately 97 % within 24 h of incubation. Administration of EVs loaded with oligodeoxynucleotides (ODN) resulted in a 4-fold increase in $IFNy^{+}$ $CD4^{+}$ T cells and a 5-fold increase in $IFNy^{+}$ $CD8^{+}$ T cells in the spleens and lymph nodes. Additionally, the co-administration of EVs with ODN and ovalbumin (OVA) induced elevated Th1-biased antibody responses and antigen-specific cytotoxic T-cell responses, providing long-lasting complete protection in 60 % of mice against T-cell thymoma challenge. Furthermore, EVs associated with three different ligands (OVA, CpG-ODN, and α-GalCer) effectively regressed established murine melanoma and significantly improved survival rates in mice. This study presents a powerful and promising approach to overcoming the limitations of EV-based cancer vaccines, advancing the development of effective cancer immunotherapies.