La Sota-vectored recombinant vaccine with chimeric hemagglutinin-neuraminidase for enhanced protection against highly pathogenic pigeon paramyxovirus type 1

Pigeon Paramyxovirus Type 1 (PPMV-1), an antigenic and host variant of the Newcastle Disease Virus (NDV), can infect pigeons of all ages and cause severe economic losses in the poultry industry. The existing commercial vaccines are not capable of providing complete protection against the prevalent PPMV-1 strains. To address this issue, reverse genetic technology was employed to create a recombinant 167DM strain by incorporating the chimeric genotype Ⅵ hemagglutinin-neuraminidase (HN) with La Sota as the backbone. The optimal anti-PPMV-1 vaccine candidate was identified through a systematical comparison of biological characteristics and immune efficacy of the predominant PPMV-1 epidemic strain, the 167DM strain, and the La Sota strain. Results indicated that the 167DM strain exhibited the highest culture titers in allantoic fluid and the strongest heat resistance. The antibody titers in the 167DM vaccine group consistently surpassed those in other groups tested. Cross-hemagglutination inhibition (HI) tests revealed no detectable antigenic differences between the 167DM and the prevalent PPMV-1 strain. Furthermore, the 167DM strain conferred 100% protection by preventing PPMV-1 infection and completely inhibiting virus shedding. These findings provide valuable insights for the development of a novel vaccine targeting ND in pigeons, thus laying a foundation for further advancements in vaccine development within this avian population.