The Genetic Evolution Analysis And Immunogenicity Research Of Newcastle Disease Virus Of Pigeon Origin

Newcastle diseases virus(NDV) can cause acute, spirited, septic and highly contagious disease in a variety of birds. In recent years, Newcastle disease(ND) has become more and more popular in pigeon. Because of the wide activity range of the pigeon, the infectious etiology they carrying seriously threatens the healthy development of the poultry industry. Genetic evolution analysis and immunogenicity research was carried out on the NDV of pigeon origin, which was of great significance to the healthy development of the poultry industry.Newcastle diseases virus harms the poultry industry all over the world, and raises the governments’ attention. In this experiment, we designed a pair of NDV general identifying primers, and categorized the 8 NDV strains isolated from different areas through biological genetic evolution analysis of genotyping related sequence in F. The genetic evolution analysis revealed that, Du/China/SD/133 strain and Ch/China/SD/128 strain belonged to class Ⅱ genotype Ⅶ;Du/China/SD/143 strain belonged to class Ⅰ; Mixed infection of classⅠand classⅡgenotype Ⅶ NDV were found in Ch/China/SD/125; Strains isolated from pigeon such as Pi/China/SD/2012/132(ND132), Pi/China/SH/2013/163(ND163), Pi/China/SH/2013/167(ND167), Pi/China/SH/2013/168(ND168) belonged to the classⅡgenetypeⅥb.We also detected mixed infection with a gengtypeⅡstrain highly homologous to La Sota in the epidemic material of ND163 and ND168, which was speculated to derive from immunity of La Sota, suggesting the La Sota vaccine couldn’t protect the pigeon against NDV of pigeon origin well.In order to confirm the evolutionary relationship between the popular pigeon strains in China, we designed a serious of NDV genome amplification primer to determine the whole sequence of 4 pigeon-souce NDV strains isolated from Shanghai and Shandong. The genetic evolution analysis of each gene suggested that the 4 isolated strains of ND132, ND163, ND167 and ND168 belonged to class Ⅱ genotype Ⅵ b, which was the same as the other popular Chinese strains, and they had a high affinity with the European isolated strains of pigeon origin. It implied that the four strains might be transferred to China from Europe through pigeon racing. The F and HN protein of them were in conformity with the significant sequence characteristics of virulent virus, and their antigenicity and hydrophobicity differed from the chicken NDV, but some important antigen epitope did have changed. The genetic analysis of the virus of pigeon origin provided a theoretical basis to the research of NDV vaccine of pigeon origin.In order to determine whether there was any immunogenic differences, we compared the serological difference and immune protection efficity between NDV of pigeon origin and La Sota in this study. The attenuated emulsion vaccine prepared with ND167 did not have ideal protection on pigeons in this experiment. Serological test showed a great immunogenic difference between v NDV of pigeon origin and La Sota, which was not completely consistent with the bioinformatics analysis results, suggesting that the mutation of some amino acids might affect the spatial epitope of antigen protein in NDV of pigeon origin. Therefore, it is a risk to immune pigeon with the La Sota attenuated vaccine or the conventional vaccine in practice. We are in badly need of a vaccine exclusive to pigeon for the healthy development of pigeon industry.We carried out the research of specified monoclonal antibody against the genotype Ⅵ NDV,aiming to compare the immunogenic differences between the ND popular in pigeon and the classical vaccine strain La Sota. We used the ND167 isolated from Shanghai as immunogen to immune BALB/c mice, and eventually acquired four strains of monoclonal antibodies. Cross ELISA results revealed a big difference of the 4 monoclonal antibodies reactivity against different NDV strains. The range of ELISA titer to La Sota of different monoclonal antibodies was more than 500 times. We obtained monoclonal antibodies against the specific antigen of NDV of pigeon origin, which laid a foundation of the subsequent screening of the specific antigen of NDV of pigeon origin, and provided technical support for clinical pigeon ND diagnosis and immunogenicity analysis in clinical production.