Comparative Evaluation of Polymeric Nanocarriers for DNA Vaccine Delivery Against Avian Orthoavulavirus 1 in Chickens

Vaccination represents the cornerstone of Newcastle disease control. Nanotechnology offers a promising approach to improve the effectiveness of DNA vaccines, supporting their use as an alternative to conventional platforms. Herein, the Avian Orthoavulavirus 1 (AOAV-1) fusion (F) gene was cloned into a DNA expression plasmid (pDNA). After validating the constructed pDNA-F and confirming robust intracellular protein expression in vitro, three polymeric nanoparticles (NPs)-based formulations were generated using Chitosan (Cs), poly(lactic-co-glycolic) (PLGA), and poly(amidoamine) (PAMAM)-Dendrimers. Physicochemical characterization, stability assessment, and in vitro release analysis confirmed nanoparticle formation and effective DNA incorporation. In vivo experiments were conducted to comparatively evaluate the immunogenicity, particularly the immune priming capacity, and protective efficacy of nanoparticle-based formulations and naked pDNA-F, all tested in parallel at standardized pDNA doses via intranasal (IN) and intramuscular routes. PAMAM-Dendrimers-pDNA-F IM group demonstrated superior efficacy, with 100% survival, the highest post-challenge anamnestic antibody titers, and a pronounced reduction in viral RNA shedding. PLGA-NPs-pDNA-F IN group demonstrated enhanced efficacy, with 90% survival. Naked pDNA-F surpassed the Cs-NPs-pDNA-F in both immune priming and clinical protection, with Cs-NPs-pDNA-F exhibiting the lowest overall performance. These findings highlight that DNA vaccine performance depends on both carrier type and administration route, with PAMAM dendrimers and PLGA enhancing efficacy, whereas chitosan demonstrated reduced efficacy under the tested conditions.