| Avian paramyxovirus type 1 (APMV-1) is one of the most devastating pathogens of poultry industry, which mainly causes Newcastle disease in chicken, APMV-1 infections in goose, And it is reported that some biological characteristics including the virulence and its associated genes, pathogenicity and immunogenicity among the APMV-1 isolates from different poultry species are not fully identical. Therefore, APMV-1 infections in pigeon, etc. Therefore, it is very necessary to make the comparison of the main biological characteristics for searching after the mechanism of evolution, infection and spread of viruses, and epizootiology of the disease.The N-terminal of nucleocapsid (NP) protein gene of 9 APMV-1 isolates, who are gxcl, gxc48, gxp35, gxp40, gxgf47, gxt54, gxpc52, gxq55, gxg44, were amplified by reverse-transcriptase polymerase chain reaction (RT-PCR), sequenced, and their genetic relationships were analyzed by performing the alignrrient and constructing the phylogenetic tree based on the sequences. The results showed that two isolates the 110 amino acid (Aa) sequences strains gxp35 and gxc48 have 6 nt longer than the published NDV genome of strains Clone-30 in NP gene. This additional 6nt motif was located in the non-coding region of NP gene between the corresponding positions·1647nt and 1648nt on the NDV genome of strain C30. The others have not this characteristic. Compared the obtained gene sequence of all isolates by DNASIS software, their homology of the nucleotide sequence were 99.8%, except comparing to those of isolates gxp35 and gxc48 by 76.4% homology. The phylogenetic tree based on the nucleotide sequences of non-coding region of NP gene revealed that APMV-1isolates gxp40, gxg44, gxcl, gxpc52, gxgf47, gxq55 and gxt54 have the same genetic affinity, since isolates gxp35, gxc48 and ZJ1 belong to another genetic affinity. The phylogenetic tree based on the 110 amino acid (Aa) sequences at the N-terminal revealed that the same results as that of the results based on the nucleotide sequences of non-coding region of NP gene. In addition, the Aa sequences 401~410 in coding region of NP gene of 6 APMV-1 isolates without a 6-nt insertion have a character sequences: NTTQQEPPS. Similarly, 401~407 Aa in coding region of NP gene of 2 APMV-1 isolates and seven other reference isolates published on GenBank with a 6-nt insertion have another character sequences: STTHPE.The experiments for searching the effect of vaccine were preformed in chickens, quails, geese and pigeon by using the oil-emulsion (IOE) vaccines prepared from the NDV stains of gxgf47, gxt54, gxpc52, gxq53, gxcl, gxp35, gxg44 and C30 and live vaccines C30. Sera of the birds were collected and detected for HI antibody against NDV at 4 weeks post-immunization (PI), and then the birds were challenged with the virulent NDV at 5 weeks PI. In pigeons, HI titers were 9.00~10.0. With the challenge of gxcl, gxp35, F48E8, the protection rates were 100%, 80%, 80% respectively in the group vaccinated with gxp35, all of 80% in the gxcl group and 100%, 100%, 80% respectively in the C30 group, which showed the best immunity effect of C30. In chickens, HI titers were 9.00~10.0. With the challenge of F48E8 or gxcl, the protection rates were 66.7%~100% in the group vaccinated with gxpc52, gxt54, C30, gxq53 , gxgf47 and gxp35. The results showed the IOEs were similar in the immunity effect. In geese, HI titers of the group vaccinated with OIE vaccines were 5.63~6.38, while that of the group vaccinated with live vaccines were 3.38. With the challenge of gxq53, gxp35, gxgf47, gxpc52, the protection rates all were 100% in the group vaccinated with C30, while with the challenge of gxcl and gxt54, those both were 80%. With the challenge of gxq53, gxp35 , gxpc52 , gxgf47, gxt54, the protection rates all were 100% in the group vaccinated with gxg44. But it is low in the group vaccinated with live vaccines C30 with the challenge of gxg44, only 20%. The result showed that the IOE vaccines prepared from gxg44 was the best immunity effect, turns to others IOE vaccine...
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