In order to potentiate the low immunogenicity of the inactivated Newcastle disease virus immunized into chickens by mucosal route, liposomes as a drug delivery system and LPS (lipopolysaccharide) as an immuno-stimulator were evaluated. Here, we report a new nasal delivery system of inactivated Newcastle disease virus (NDV) vaccine. The intranasal vaccine was based on different lipids to form MLV (multi-lamellar vehicles) liposomes. The liposomes had combined carrier and adjuvant activities, which induced strong systemic (serum) and local (lung and nasal) humoral responses in SPF (specific-pathogen-free) chickens, and provided protective immunity. PC-Lip (phosphatidylcholine-liposome) elicited significant mucosal secretary immunoglobulin A (s-IgA) levels (p <0.05) in tracheal lavage fluid and serum IgG levels (p <0.05). In response to virulent viral challenge, birds treated with PBS (phosphate buffered saline) as control group died, whereas 80% of chickens which received PC-Lip, PC-Lip-LPS, PS-Lip (phosphatidylserine-liposome), and PS-Lip-LPS survived. HAI titers were 1:2560 in the PS-Lip-LPS group and 1:1280 in the PC-Lip, PC-Lip-LPS, and PS-Lip groups after two vaccinations. The results suggest that PC-Lip or PS-Lip might thus be suitable as a potential adjuvant for mucosal vaccination against NDV in chickens.
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