Establishment of a live vaccine strain against fowl typhoid and paratyphoid / 대한수의학회지

To develop a live vaccine strain against fowl typhoid and paratyphoid caused by Salmonella serovar Gallinarum biovar Gallinarum (Salmonella Gallinarum) and Salmonella serovar Enteritidis (Salmonella Enteritidis), respectively, several nalidixic acid resistant mutants were selected from lipopolysaccharide (LPS) rough strains of Salmonella Gallinarum that escaped from fatal infection of a LPS-binding lytic bacteriophage. A non-virulent and immunogenic vaccine strain of Salmonella Gallinarum, SR2-N6, was established through in vivo pathogenicity and protection efficacy tests. SR2-N6 was highly protective against Salmonella Gallinarum and Salmonella Enteritidis and safer than Salmonella Gallinarum vaccine strain SG 9R in the condition of protein-energy malnutrition. Thus, SR2-N6 may be a safe and efficacious vaccine strain to prevent both fowl typhoid and paratyphoid.

Sequence Analysis of the Gene Encoding gp55 Protein of Suri Strain, an Attenuated Classical Swine Fever (Hog Cholera) Virus

An attenuated classical swine fever virus (CSFV), Suri strain, is a va.iant derived from a vaccine virus, LOM strain. This study was performed to elucidate the molecular biologcal properties of CSFV Suri strain, and to obtain the basic data for molecular epidemiological approaches for the disease. The truncated form of gp55 gene without the C-terminal transmembrane domain, in size of 1,023bp, was amplified by RT-PCR and sequenced by dye terminator cyclic sequencing method, and inserted into BamHI site of pAcGP67B baculovirus vector, establishing a cloned pAcHEG plasmid. By the nucleotide sequences determined, 341 amino acid sequences were predicted. As compared the nucleotide and amino acid sequences of gp55 of Suri with the various CSFV, Suri strain showed the high homology over 99.1% with ALD and LOM strains, but comparably the lower homology with Alfort and Brescia. In comparison of amino acid sequence in variable domain of gp55 protein, the similar tendency of homology was observed. In hydrophobicity analysis, all of four CSFV strains revealed the analogous patterns of hydrophobicity. The numbers and locations of N-glycosylation site and cysteine residues in gp55 were analyzed, those of Suri strain being coincident with ALD and LOM strains. The results suggest that gp55 in Suri strain has the high similarity to those in ALD and LOM strains in terms of the nucleotide and amino acid sequences and the functional properties of gp55 protein..