W163 - Injectable Fatty Acid Nanovesicles as Next-generation Vaccine Adjuvant: ‎integrating Physicochemical Characterization with Cytokine-mediated ‎immunomodulation

Abstract Text: Injectable docosahexaenoic acid (DHA) nanovesicles were formulated using film hydration ‎method, characterized for their physicochemical and morphological properties. Transmission ‎electron microscopy confirmed smooth, discrete structures with ‎consistent ‎morphology. The ‎vesicles displayed uniform spherical shapes, high colloidal stability, optimal surface ‎charge and ‎good poly dispersity index. Thermal and structural stability were validated by differential ‎scanning calorimetry, thermogravimetric analysis, X-ray diffraction, and nuclear magnetic ‎resonance spectroscopy, supporting their suitability as injectable nano dosage form. ‎Immunological studies in Wistar rats revealed that the DHA nano vesicles showed a stronger ‎and more sustained immune response than the commercial hepatitis B vaccine. Elevated levels ‎of pro-inflammatory cytokines, interleukin-6 (IL-6), interleukin-8 receptor (IL-8R), and ‎interleukin-12 (IL-12) indicated activation of innate immunity and antigen-presenting cells. ‎Simultaneously, upregulation of interleukin-2 (IL-2), IL-4, IL-10, and interferon-gamma (IFN-‎γ) reflected stimulation of adaptive immunity and immunological memory. Increased C-‎reactive protein (CRP) confirmed systemic immune activation, while stable immunoglobulin E ‎‎(IgE) levels indicated no hypersensitivity. Overall, the DHA nanovesicle adjuvant system ‎demonstrated an excellent vaccine adjuvant for enhancing hepatitis B vaccine immune ‎response.‎