Isolatl On And Identification Of Porcine Adenovirus Type 3

Porcine adenovirus type 3(PAdV-3),with intestinal tropisim andstrict host specificity, is non-pathogenic to pigs. PAdV-3 can induce strong humoral, cellular and mucosal immunity without additional adjuvant and it can be used for large-scale production. The forementioned advantages make PAdV-3 as an ideal vaccine vector. Currently,PAdV-3 and PAdV-5 have obtained the complete sequence. They have been used for vectored vaccine and obtained the better effect. In order to obtain the strain of PAd V-3 isolated in China as vehicle for vaccine delivery, the intestinal tissue samples from healthy pigs were collected for virus isolation by ST cells. The hexon and p IX genes of virus isolation were sequenced and analyzed. The main results are as follows:1. By inoculation and replication in ST cells. One strain, named BJ14 from Beijing, and three strains,named Ben23, Ben29 and Ben30 from Shaanxi Province were isolated.2. The fragments of partical conserved hexon(Nested-PCR product) of above five adenoviruses, full-length hexon of strains Ben29, Ben30 and Ben33, and full-length p IX of strain Ben30 were amplified, cloned, sequenced and further analysed by bioinformatics software of DNA star and Clone Manager.First, nucleotide sequence analysis of partical conserved hexonfrom five strains showed that five strains had nucleotide homology from 98.2% to 99.7%. The five strains had nucleotide homology above 98.2%with reported strains of 6618, IAF and PAV-3. Besides, The five strains had nucleotide homology below 76%with other porcine adenovirus.Second, nucleotide sequence analysis of hexon genes of strain Ben29,strain Ben30 and strain Ben33 showed that Ben33 had nucleotide homology 81.6%with Ben29 and Ben30; Ben29 and Ben30 had nucleotide homology above 99.5%with IAF and 6618.; Ben33 had nucleotide homology above 81.2%with IAF and 6618.Third, by epitope prediction software,we found that Ben29,Ben30 and Ben33 had the same antigenic epitopes with the classical PAdV-3 strain of 6618. However, the antigenic epitopes of the three strains were quite different from PAdV-5’s.Fourth, nucleotide sequence analysis of p IX genes of stran Ben30,strain6618,strain IAF and strain PAV-3 showed that p IX genes of Ben30 had amino acid homology 91% with strain 6618,strain IAF and classical strain.In conclusion, we isolated three strains of PAdV-3 in China, which paved the foundation for the further construction of infectious clone of PAdV-3 and study of biological characteristics of porcine adenoviruses type 3.