Evaluation of encapsulated Newcastle disease virus liposomes using various phospholipids administered to improve chicken humoral immunity

We propose the adjuvant effects of phospholipid liposome compositions using intranasal inoculation of a liposomal-Newcastle disease virus (NDV) vaccine in chickens. The immunogenicity of three liposome formulations was determined in chickens using the hemagglutination-inhibition (HI) test, nasal secretory immunoglobulin A and serum immunoglobulin A (IgG) antibody titers using the enzyme-linked immunosorbent assay. The immune response against NDV antigens was determined after immunization with neutral charged liposomes composed of egg phosphatidylcholine (EPC) (60 μmol), cholesterol (Chol) (15 μmol), and EPC-liposomes (EPC-Lip), which elicited strong systemic (serum) and local (nasal) humoral responses. However, the intranasal administration with cationic charged liposomes composed of EPC (30 μmol), stearylamine (SA) (15 μmol), Chol (15 μmol), and SA-liposomes (SA-Lip) induced poor humoral immune responses. Only the vaccine formulated with anionic charged liposomes composed of EPC (30 μmol), dipalmitoylphosphatidylserine (15 μmol), Chol (15 μmol), and phosphatidylserine-liposomes (PS-Lip) elicited the highest titers of HI antibodies. These are the first results to suggest that antigen delivery using EPCLip is very useful in enhancing antibody production at the mucosal site and in serum.