Hee Jong Song

National Veterinary Research Quarantine Service, Sŏul, Seoul, South Korea

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Publications (6)7.23 Total impact

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    ABSTRACT: A murine model immunized by systemic and mucosal delivery of plasmid DNA vaccine expressing glycoprotein B (pCIgB) of pseudorabies virus (PrV) was used to evaluate both the nature of the induced immunity and protection against a virulent virus. With regard to systemic delivery, the intramuscular (i.m.) immunization with pCIgB induced strong PrV-specific IgG responses in serum but was inefficient in generating a mucosal IgA response. Mucosal delivery through intranasal (i.n.) immunization of pCIgB induced both systemic and mucosal immunity at the distal mucosal site. However, the levels of systemic immunity induced by i.n. immunization were less than those induced by i.m. immunization. Moreover, i.n. genetic transfer of pCIgB appeared to induce Th2-biased immunity compared with systemic delivery, as judged by the ratio of PrV-specific IgG isotypes and Th1- and Th2-type cytokines produced by stimulated T cells. Moreover, the immunity induced by i.n. immunization did not provide effective protection against i.n. challenge of a virulent PrV strain, whereas i.m. immunization produced resistance to viral infection. Therefore, although i.n. immunization was a useful route for inducing mucosal immunity at the virus entry site, i.n. immunization did not provide effective protection against the lethal infection of PrV.
    Journal of Microbiology and Biotechnology 04/2008; 18(3):591-9. · 1.40 Impact Factor
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    ABSTRACT: To assess the correlation between the nature of immunity induced by different types of immunogens and the establishment of latent infection by wild-type pseudorabies virus (PrV), we used a murine model immunized with different immunogens, the PrV modified live vaccine (MLV), inactivated vaccine (IAV), and commercial oil-adjuvant subunit vaccine (OSV), via either intranasal (i.n.) or intramuscular (i.m.) route. Both MLV and IAV induced a different nature of immunity biased to Th1- and Th2-type, respectively, as judged by the ratio of PrV-specific IgG isotypes (IgG2a/IgG1) and the profile of cytokine IL-2, IL-4, and IFN-gamma production. In contrast, the OSV induced a lower isotype IgG2a to IgG1 ratio and higher level of IL-2 production. The MLV (inducing Th1-type) provided more effective protection against a virulent wild-type PrV challenge than IAV and OSV (inducing Th2- and mixed type, respectively). In addition, the MLV impeded the establishment of a latent infection with wild-type PrV, and the decrease in the PrV latency load by immunization with the MLV appeared to be mediated by the immune T-cells. These results demonstrate the substantial role of the immune responses driven by preceding vaccination in modulating the establishment of PrV latency caused by the post-infection of a field virus.
    Research in Veterinary Science 09/2007; 83(1):73-81. · 1.77 Impact Factor
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    ABSTRACT: It was reported that the sera of convalescent animals contain antibodies to foot and mouth disease (FMD) virus (FMDV) 2C, highly conserved nonstructural protein (NSP), whereas the sera of vaccinated animals do not. But ELISA methods using this protein were not reported and developed until recently. In this study, NSP 2C peptides were synthesized within the amino acid sequence of the conserved 2C nonstructural region of FMDV according to the sequences from Genbank database and used for identifying antigenic determinants. One of the synthesized thirteen peptides gave strong positive reactivity with most of the sera from 13 FMD infected farms, but not with sera from vaccinated and non-infected animals. Moreover, with the sera collected through serial bleedings from four cattle and five goats infected with FMDV O/SKR/2000 experimentally, positive results were obtained in two species after 10 days post infection (DPI). Therefore, we tried to develop and evaluate this ELISA based on 2C peptides. In comparison with the commercial NSP ELISA, the 2C peptide based ELISA method showed good specificity and sensitivity. These results demonstrate that the synthetic 2C peptide ELISA can be a complementary marker to differentiate FMDV-infected from vaccinated on a herd basis.
    Journal of Veterinary Science 01/2006; 6(4):317-25. · 0.93 Impact Factor
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    ABSTRACT: In this study, the prevalence and quantity of a latent pseudorabies virus (PrV) infection in the nervous tissues of randomly selected pigs was determined via nested and real-time PCR. The nervous tissues, including the trigeminal ganglion (TG), olfactory bulb (OB), and brain stem (BS), were collected from the heads of 40 randomly selected pigs. The majority of the nervous tissues from the selected pigs evidenced a positively amplified band on nested PCR. In particular, nested PCR targeted to the PrV glycoprotein B (gB) gene yielded positive results in all of the BS samples. Nested PCR for either the gE or gG gene produced positive bands in a less number of nervous tissues (57.5% and 42.5%, respectively). Real-time PCR revealed that the examined tissues harbored large copy numbers of latent PrV DNA, ranging between 10(0.1) and 10(7.2) (1-1.58 x 10(7)) copies per 1 microg of genomic DNA. Real-time PCR targeted to the PrV gE gene exhibited an accumulated fluorescence of reporter dye at levels above threshold, thereby indicating a higher prevalence than was observed on the nested PCR (100% for BS, 92% for OB, and 85% for TG). These results indicate that a large number of farm-grown pigs are latently infected with a field PrV strain with a variety of copy numbers. This result is similar to what was found in association with the human herpes virus.
    The Journal of Microbiology 11/2005; 43(5):430-6. · 1.28 Impact Factor
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    ABSTRACT: One step TaqMan real-time reverse transcription polymerase chain reaction (R/T RT-PCR) using a set of primers/probes was developed for the detection of foot-and-mouth disease (FMD) virus. The gene-specific probes labeled fluorogen for the internal ribosomal entry site, Leader sequence and 2B regions were used to detect FMD virus (FMDV). This assay specifically detected FMDV both in cell culture preparations and clinical samples, and was capable of distinguishing FMD from other viral diseases similar to clinical signs (swine vesicular disease, vesicular stomatitis and bovine viral diarrhea). This assay was shown to be 1000-fold more sensitive than the conventional RT-PCR method. The detection limits of this assay was 1 TCID(50)/ml of the FMDV RNA concentration. Quantification was obtained by a standard curves plotting threshold cycle values versus known infectivity titer. The assay was sensitive, specific and rapid enough to detect FMDV RNA genome in probang samples. As such, the described method is reliable and provides faster disease diagnostics than the conventional RT-PCR procedure to detect FMDV.
    Journal of Veterinary Science 10/2005; 6(3):207-12. · 0.93 Impact Factor
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    ABSTRACT: From May to June 2002, a total of 16 foot-and mouth disease (FMD) outbreaks due to the serotype O virus, Pan Asia strain, were recorded in Korea. The viruses were identified by antigen ELISA, RT-PCR and sequence analysis. The overall nucleotide sequence divergence of the VP1 region among the 4 isolates in 2002 was 0 to 1.4%, but between O/SKR/2002 and O/SKR/2000 isolates was 1.9-4.9%. Phylogenetic analysis with the some known strains from East Asian countries showed that the 4 Korean isolates in 2002 formed one distinct cluster, which different from clusters of Korean isolates in 2000, with in the same lineage of the ME-SA topotype strains. Deduced amino acid sequences around neutralizable antigenic site on VP1 site of O/SKR/2002 isolates were aligned and compared with other strains. At the antigenic site 1, the replacements of the critical amino acid residues at position 144 from V to L and at position 152 from A to T were observed in O/SKR/2002 viruses. For antigenic site 2 and 4, there were not significant variations in general. At the antigenic site 3, the substitutions of amino acid residues were present at positions 54 and 56 in O/SKR/2002 isolates and an alternative residue I at position 54 are observed only at the sequence of O/SKR/AS/2002 (cow) virus. And the substitution (L-->P) of significant residue at position 144 was detected at the amino acid sequence of the O/SKR/2002 (cow) virus.
    Journal of Veterinary Science 06/2005; 6(2):117-24. · 0.93 Impact Factor