[Nucleotide sequence analysis of E2 major protective antigen encoding region of 12 strains of hog cholera virus(HCV)]

cDNA fragments, of HCV envelope glycoprotein E2 major gene of 11 field strains isolated in China in different time and 1 French reference strain(Thiveral) were amplified respectively with RT-PCR method and sequenced. The fragments amplified located by the 5' 2485 to 2708 of E2 major domains B and C and encoded 75 amino acid residues of E2 glycoprotein. All the products amplifield by RT-PCR from 12 strains in the study were same size of 224 bp. Comparing 12 sequences with other 9 references strains sequence reported before using software DNAstar, it was found that Hog Cholera Virus could be classified in two groups by analysis of phylogenetic tree. Strains Brescia, Gpe, Ald, Thiverval, C, CW, HCLV, HCVSM, BJCY1/96, BJTX3/96, BJSY2/96, HeNXH2/98, HeNZZ1/82 and GDGZ1/95 were assigned to group A and were 85.7%-100% for nucleotide sequence and 83.8%-100% for amino acid sequence in homology; but strains HCVF98, HCVF94, HeBHH2/95, LN1/84, SZGM1/85, SCCD1/79 and Alfort were assigned to group B and were 84.3%-100% for nucleotide sequence and 85.1%-100% for amino acid sequence in homology; and 21 strains of HCV were 78.1%-100% for nucleotide sequence and for 78.4%-100% amino acid sequence in homology. Homology were 99.1% for nucleotide sequence and 100% for amino acid sequence between strains HCLV in our study and strains C reported by Rijn's in the Netherlands. It's showed our method of sequencing is reliable. There were obvious differences between the two groups in sequences of envelope glycoprotein E2 major gene, especially in the amino acid substitutions of sites 713 and 729 respectively, and it is showed the two groups of HCV field strains might vary genetically in some extents. The results of other report of challenging of the partial field strains showed that the Chinese stock vaccine virus(HCLV) has good immunity.