Immune Responses Following Vaccination of Chickens With a Liposomal Newcastle Disease Virus HN-DNA Vaccine

Introduction: Newcastle disease virus (NDV) is an economically important infectious agent causes a respiratory and neurological disease in many species of birds. In addition to the conventional vaccines that are applied depending on the disease situation, new platforms have been investigated for the development of next-generation vaccines. The hemagglutininneuraminidase (HN) glycoprotein of NDV plays a crucial role in the immune response and serves as a potential target for the development of DNA vaccines. Liposomes can effectively target specific immune cells to elicit both humoral and cell-mediated immune responses. Materials & Methods: In this study, the conserved coding sequence of the HN gene extracted from the NDV clone strain was loaded into liposomes. Physicochemical parameters such as size, charge, encapsulation efficiency, and morphology of the entrapped DNA were determined to ensure optimal vaccine efficacy. Two-week-old chickens received two doses of the vaccine with a one-week interval. The immunogenicity of the liposomal HN-DNA vaccine was evaluated using hemagglutination inhibition (HI) and cutaneous basophil hypersensitivity (CBH) assays in ۲-week-old specific pathogen-free chickens over a ۵-week post-vaccination period. Results: The HN-DNA liposomes had an average size of ۱۶۶.۶±۴.۶۵ nm, a polydispersity index (PDI) of ۰.۱۱۷, a positive surface charge of ۱۳.۷±۸.۷۱ mV, an encapsulation efficiency of ۵۶.۴±۸.۳%, and a homogeneous and spherical structure. A prime-boost vaccination with HNDNA liposomes resulted in increased HI antibody titers, demonstrating a consistent immunization pattern of initial rise, peak, and decline. Furthermore, immunizing chickens with the HN-DNA vaccine significantly enhanced the CBH response, demonstrating its effectiveness in inducing cell-mediated immunity. Conclusion: Overall, the liposome vaccine containing HN-DNA is highly promising and should be prioritized for further investigation as an effective booster in NDV prevention strategies.

کلیدواژه ها:

Newcastle disease virus (NDV) ، cationic liposome ، DNA vaccine ، Hemagglutininneuraminidase (HN) ، Immune response