Immune Efficacy Of Newcastle Disease Virus-like Particles

In order to study the immune efficacy of Newcastle Disease Virus-like particles (VLPs), NDV F48E9 VLPs production system had been established with recombinant baculavirus that coexpress M, NP, F and HN proteins. ND-VLPs, which prepared by this system, have the authentic conformation of virus and HA reactive (10μg VLPs contain 128U HA). The yield of ND-VLPs was 1.57mg/100ml, each protein content in 10μgVLPs was estimated as follows,HN:0.76-1.14μg, F:0.38-0.76μg, NP:1.14-1.52μg, M:0.67-0.95μg . In this work, we present data on the immunogenicity and protective efficacy afforded by ND-VLPs following immunization of SPF chickens. SPF chickens were vaccinated intramuscularly twice at 2-week interval with ND-VLPs formulated with Freund's adjuvant in different dose based on total protein concentration (10, 20, 25μg), and the immune responses were compared to responses elicited in chickens vaccinated with whole NDV (La Sota strain) or La Sota combined with ND-VLPs, by either intranasal instillation or intramuscular injection. All vaccinated chickens demonstrated HI antibody titer, specific IgG and neutralizing antibody against NDV, and intranasal instillation group also elite IgA. Intramuscular injection of 25μg ND-VLPs protected 100% chickens from challenged with 3.16×10³ EID₅₀ /100μl velogenic NDV F₄₈E₉ strain, but intranasal instillation of it only protected 90% chickens from challenge. In addition, we found that chickens administrated with La Sota combined with ND-VLPs elicited the higest antibodies titer among all groups. It suggests that ND-VLPs could complement efficacy of La Sota vaccine against F₄₈E₉.ND-VLPs, have been assembled effectively in the insect-cell-based protein production system, immune studies showed good immunogenicity and conferred complete protection against a lethal NDV challenge. Take together, Not only do these results suggest a novel approach to the development of VLPs vaccines for diverse NDV strains, but also the creation of multivalent vaccines by decoration of the surface of the VLPs with antigens from different epidemic strains or even other pathogens.