Rotaviruses are the most common cause of severe vomiting and diarrhea in children worldwide and classified as a genus in the family Reoviridae. Rotavirus has eleven segmented dsRNAs and the virion consists of three shells. Outer capsid VP7 and VP4 induce neutralizing antibodies and are classified into G types (glycoprotein VP7) and P types (protease-sensitive VP4). Characterization of VP7 gene of Korean isolates of human rotavirus was performed using multiplex PCR and nucleotide sequence analysis. After RT-PCR amplification of full length (1,062 bp) of VP7 genes, the amplified PCR products were G typed by multiplex PCR and the nucleotide sequences were compared with those of reference rotavirus from GenBank. The G type analysis revealed that 25% (2/8) belong to G1, whereas 37.5% (3/8) benong to G2 and G4, respectively. The Korean isolates within the same serotypes showed high homology of nucleotide sequences and could be discriminated from foreign isolates exception with two strains (CAU009 and CAU022). But Korean isolates CAU009 and CAU022 were close related into japanease isolates 417 (99.2%) and indian isolates (97.6%) than Korean isolatese. Our results showed that these two strains were supposed to be originated from abroad. As a results, The G typing and nucleotide sequence analysis of VP7 gene of rotavirus isolated from infants in Korea could be used for identification, serotying and determination of novel or unusual strains of rotaviruses.

We had isolated 8 viruses from 91 specimen collected at southwest Cheju Province during early spring 1998 and 2 viruses from 9 specimen collected at Chung Nam Province during early spring 1999. To perform cross-reactivity among 4 mumps vaccine strains and 10 wild-type mumps viruse isolates, we immunized mice and took antisera against each virus. There were no antibody titer differences by indirect immunofluorescence assay (IFA), but most isolated mumps viruses showed a little cross-reactivities with Jeryl Lynn and Rubini strains. It has shown similar result by haemagglutination-inhibition (HAI) test. These results show that 4 mumps strains used as vaccine have the protection ability against endemic wild-type mumps viruses. Also the SH gene analysis was performed to identify genotypes. Most isolated mumps viruses belonged to genotype D. These results indicate that endemic mumps viruses in Korea are different to ones isolated in Japan and China.

Infection with human cytomegalovirus (HCMV) is of considerable clinical relevance after placental transmission and in immunosuppressed patients such as transplant recipients or patients with AIDS. The rapid detection method of HCMV has been required to overcome the time-consuming methods such as classical plaque assay or other immunological methods. This study was performed to establish the in situ ELISA, in which human lung fibroblasts infected with HCMV were fixed and used directly as antigen in 96 well culture plate. Expressed HCMV antigens were detected with HCMV-specific monoclonal antibodies. This method could detect HCMV dose-dependently upto $3{\times}10^2\;pfu/ml$. Antiviral activity of ganciclovir could be assayed within the known range of effective dose. This result showed that HCMV could be quantitated by in situ ELISA. The chemical, which was selected on the basis of component analysis in natural product, was tested to have the anti-HCMV activity by in situ ELISA, and three among five samples were found to have anti-HCMV activity with the dose-dependent manner. Conclusively in situ ELISA could be useful method for quantitation of HCMV and screening antiviral activity of samples to HCMV.

Bovine leukemia virus (BLV) is an etiological agent of chronic diseases in cows worldwide. The BLV is one of retroviruses that contain a multi-functional enzyme, reverse transcriptase produced from the pol gene in its genome. We have sequenced some regions in the pol gene of BLV proviruses found in the Southern province of Korea from samples that turned out to be BL V positives by a PCR analysis. On the 5' side of the BLV pol gene (polymerase region), it was found that there were four leucines located at every 7 amino acids. They can form a leucine zipper motif that was not same as the pol gene of Japanese BLV isolate. The sequencing result of the proviral pol gene in Korean-type BLV also revealed some mutations leading to amino acid changes such as $CCT(Pro){\to}CTC(Leu)$, $AAT(Asn){\to}AAA(Lys)$, and non-sensible variations i.e., $TCT(Ser){\to}TCC(Ser)$, $ATT(Ile){\to}ATC(I1e)$ and $ACG(Thr){\to}ACA(Thr)$. On the 3' side of the pol gene (integrase region), some nucleotide sequences were mutated and led to amino acid changes. Among them, a mutation, $GAA(Glu){\to}GAC(Asp)$ occurred in many Korean-type BLV proviruses was very interesting because the amino acid was regarded as one of the most conserved amino acids in the retroviral integrase. It was also notable that the mutation on any leucine residue did not occur, in spite of its frequent appearance.

The effectiveness of noninfectious recombinant adenovirus encoding murine granulocyte-macrophage colony stimulating factor (mGM-CSF) for the treatment of Meth A fibrosarcoma was investigated in syngeneic BALB/C model. Meth A and HeLa cells transduced with the recombinant adenovirus (Ad.mGM-CSF) produced substantial amounts of mGM-CSF, while WEH1164 cells transduced with the virus did not produce mGM-CSF. Mice inoculated subcutaneously with $1{\times}10^6$ Meth A cells, followed by injection of Ad.dE1 as a control, developed large tumors that reached a mean tumor size of 22 mm by day 30. However, tumor development and tumorigenicity were significantly inhibited in mice with a single intratumoral injection of Ad.mGM-CSF at $1{\times}10^8\;pfu$. Histological examination of the tumors injected with Ad.mGM-CSF revealed dense infiltrates of neutrophils, histiocytes, lymphocytes, and eosinophils associated with apoptotic cell death. The results suggest that the recombinant adenovirus encoding GM-CSF have a potential use for cancer gene therapy.

Hepatitis C virus (HCV) is one of the important human pathogen that can cause acute and chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. Recently, the third generation radiation immuno assay (RIA) method has been developed as a very sensitive test to detect anti-HCV antibody. However, false positive is the problem with RIA test. To solve this the RIA results were compared to those of 5-antigen recombinant immunoblot assay (5-RIBA) and reverse transcription-polymerase chain reaction (RT-PCR). Among 12,767 serum samples tested from clinic visitors, total 275 (2.2%) samples were antibody positive by RIA. RIBA was performed with 148 RIA positives cases but among them was shown eighty five was antibody positive and sixty three (42.6%) was negative result. However, nested RT-PCR test was shown also carried out with 43 positive, 6 intermediates and 25 negatives of RIBA. As a result of the nested RT-PCR results, HCV antigen were detected in RIBA positive, 33.3% (2/6) RIBA intermediate and 12% (3/25). Clinical syndrome of all 148 patients as a with chronic active hepatitis (46.0%), cirrhosis (18.9%), hepatocellular carcinoma (8.1%) and others (27.0%) and they were positive in reaction by RIA test. But RIBA positive patients with 34.9% of chronic active hepatitis, 18.6% of cirrhosis, 4.6% of hepatocellular carcinoma and 41.9% of others were detected to be positive case by nested RT-PCR.