• The Journal of Korean Society of Virology
• /
• v.30 no.1
• /
• pp.61-70
• /
• 2000

Standard plaque assay using agarose-overlay has long been used for titration of many infectious virus particle. Plaque assay for the titration of varicella-zoster virus and its live vaccine requires three intermittent agarose overlay to visualize plaques. Overall procedure of the assay takes at least nine days from virus inoculation and microbe contamination including fungi is frequently accompanied during incubation period. We studied whether an immunofocus assay in conjunction with peroxidase-mediated immunohistochemical reaction may replace the standard plaque assay for the virus titration by comparing the two methods. A linear relationship was observed between number of foci and virus dilution. The number of foci in a given dilution of virus appeared a little higher than counted plaques formed in standard plaque assay. Independent titration results obtained from two assay methods for a given dilution of virus demonstrated a strong correlation ($r^2=0.99$). Foci of virus infected cells as revealed by the enzyme reaction could be counted either 4 days post-infection (p.i.) under low magnification (40X) microscopy, or 6 days p.i. by naked eye observation. Larger size of cell cuture plate, virus adsorption at $35^{\circ}C$, and 10% FBS in diluent appeared to be better conditions for the assay. Immunofocus assay will be an effective and dependable titration method for varicella-zoster virus and its live vaccine in place of the standard plaque assay in respect to accuracy, costs, and experimental convenience.

• Archives of Pharmacal Research
• /
• v.28 no.11
• /
• pp.1293-1301
• /
• 2005

Flavonoids, a group of low molecular weight phenylbenzopyrones, have various pharmacological properties including antioxidant, anticancer, bactericidal, and anti-inflammatory. We carried out anti-herpetic assays on 18 flavonoids in five classes and a virus-induced cytopathic effect (CPE) inhibitory assay, plaque reduction assay, and yield reduction assay were performed. When flavonoids were applied at various concentrations to Vero cells infected by HSV-1 and 2, most of the f1avonoids showed inhibitory effects on virus-induced CPE. Among the flavonoids, EC, ECG (flavanols), genistein (isoflavone), naringenin (flavanone), and quercetin (flavonol) showed a high level of CPE inhibitory activity. The antiviral activity of flavonoids were also examined by a plaque reduction assay. EC, ECG, galangin, and kaempferol showed a strong antiviral activity, and catechin, EGC, EGCG, naringenin, chrysin, baicalin, fisetin, myricetin, quercetin, and genistein showed moderate inhibitory effects against HSV-1. In these experiments, flavanols and flavonols appeared to be more active than flavones. Furthermore, treatment of Vero cells with ECG and galangin (which previously showed strong antiviral activities) before virus adsorption led to a slight enhancement of inhibition as determined by a yield reduction assay, indicating that an intracellular effect may also be involved.

• Korean Journal of Pharmacognosy
• /
• v.30 no.2
• /
• pp.151-157
• /
• 1999

In order to find less toxic antiherpetic agents, the effect of natural quercetin on the plaque formation of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) was studied in vitro in cell culture monolayers employing the technique of viral plaque reduction assay. Quercetin caused a concentration-dependent reduction in the plaque formation of herpesviruses. It also exhibited more potent antiherpetic activity on HSV-1 with effective concentration $(EC_{50})$ of $18.7\;{\mu}g/ml$ than on HSV-2 with $EC_{50}$ of $24.5\;{\mu}g/ml$. The combined antiherpetic effects of quercetin with nucleoside antiherpetic agents, acyclovir and vidarabine, were examined on the multiplication of these two strains of herpesviruses in Vero cells by the combination assay. The results of combination assay were evaluated by the combination index (CI) that was calculated by the multiple drug effect analysis. The combinations of quercetin with acyclovir on HSV-1 and HSV-2 showed more potent synergism with CI values of $0.19{\sim}0.89$ for 50%, 70%, 90% effective levels than those with vidarabine with CI values of $0.43{\sim}1.46$.

• YAKHAK HOEJI
• /
• v.43 no.1
• /
• pp.77-84
• /
• 1999

To search for less toxic antiherpetic agents, the inhibitory effects of natural naringenin on the plaque formation of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in Vero cells were examined by the plaque reduction assay in vitro. Naringenin inhibited plaque formations of HSV-l and HSV-2 in a dose dependent manner. It also exhibited more potent antiherpetic activity on HSV-l with selectivity index (SI) of 19.1 than on HSV-2 with SI of 5.7 The combined antiherpetic effects of naringenin with nucleoside antiherpetic agents, acyclovir and vidarabine, were examined on the multiplication of these two strains of herpesviruses in Vero cells by the combination assay. The results of combination assay were evaluated by the combination index (CI) that was calculated by the multiple drug effect analysis. The combinations of naringenin with acyclovir on HSV-l and HSV-2 showed more potent synergism with CI values of 0.28∼0.81 for 50%, 70%, 90% effective levels than those with vidarabine with CI values of 0.86-3.28.

• Korean Journal of Food Science and Technology
• /
• v.50 no.2
• /
• pp.244-247
• /
• 2018

Quantitative analysis for non-host infection bacteriophage was conducted for their enumeration. Flow cytometry and epifluorescence microscopy (EPM) were selected as counting methods. Correlation analysis was performed based on the plaque assay method on the existing host infection and consisted of Pearson correlation statistical analysis, regression analysis, and difference analysis. Analyses of 12 samples with flow cytometry and plaque assay methods showed that there was a correlation of 96.7% with Pearson correlation value r=0.967, $R^2$ 0.9352, and difference value of 1.063. Analyses of 12 samples with EPM and plaque assay methods showed that there was a correlation of 99.0% with Pearson correlation value r=0.990, $R^2$ 0.9811, and difference value of 1.605. Therefore, flow cytometry and epifluorescence microscopy would be effective for enumeration of Weissella cibaria bacteriophage with plaque assay.

• YAKHAK HOEJI
• /
• v.43 no.4
• /
• pp.464-468
• /
• 1999

In order to find less toxic antiviral agents from basidiomycetes, EA, the water soluble substance, was isolated from the carpophores of Elfvingia applanata (Pers.) Karst. Anti-encephalomyocarditis (EMC) virus activity of EA was examined in Vero cells by plaque reduction assay in vitro. And the combined antiviral effects of EA with interferon (IFN) alpha and gamma were examined on the multiplication of EMC virus. EA exhibited a concentration-dependent reduction in the plaque formation of EMC virus with 50% effective concentration ($EC_{50}$) of 2.12 mg/ml. The results of combination assay were evaluated by the combination index (CI) that was analysed by the multiple drug effect analysis. The combination of EA with IFN alpha showed potent synergism with CI values of 0.40~0.60 for 50%, 70% and 90% effective levels, but that with IFN gamma showed antagonism with CI values of 2.16~2.83.

• The Korean Journal of Mycology
• /
• v.27 no.2 s.89
• /
• pp.175-179
• /
• 1999

In order to find less toxic antiviral agents from Basidiomycetes, EA, the water soluble substance, was prepared from the carpophores of Elfvingia applanata (Pers.) Karst. Antiviral activity of EA against vesicular stomatitis virus [New Jersey serotype, VSV(NJ)] was examined in Vero cells using plaque reduction assay in vitro. And the combined antiviral effects of EA with interferon (IFN) alpha and gamma were examined on the multiplication of VSV(NJ). EA caused a concentration-dependent reduction in the plaque formation of VSV(NJ) with 50% effective concentration $(EC_{50})$ of 2.10 mg/ml. The results of combination assay were evaluated by the combination index (CI) that was analysed by the multiple drug effect analysis. The combination of EA with IFN alpha showed more potent effect with CI values of $0.87{\sim}1.59$ for 50%, 70% and 90% effective levels than that with INF gamma with CI values of $1.05{\sim}2.03$.

• The Journal of Korean Medicine
• /
• v.23 no.2
• /
• pp.28-38
• /
• 2002

Objectives : This study was to examine the efficacy of GCT on the hepatoprotective effect in the liver function and immune octivity. Methods : The experiment to investigate the hepatoprotective effect of GCT on the liver damage was conducted with D-galactosamine. The experiments to verify the effects of GCT on the immune activity were conducted by carbon clearance assay, plaque-forming cell SRBC assay of IgM, lymphoproliferation assay of T and B cells, and adherence and phagocytosis of mocrophages. Results: In the damage of liver induced by D-galactosamine, GCT carried hepatoprotective effect on AST. In carbon clearance assay GCT showed significant effect on phagocytosis of Kuffer cells. In the plaque-forming cell assay, GCT improved the formation of IgM. In the lymphoproliferation assay, GCT activated the formation of T and B lymphocytes. In macrophages, GCT activated adherence and phagocytosis. Conclusion : Though further study is needed, our findings suggest that GCT could be recommended as hepatoprotector and immune modulator for liver disease.

• Biomolecules & Therapeutics
• /
• v.7 no.2
• /
• pp.158-163
• /
• 1999

In order to find less toxic antiherpetic agents, antiviral activities of quercitrin against two strains of pathogenic viruses such as herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) were determined in Vero cells using plaque reduction assay in vitro. Quercitrin showed a concentration-dependent decrease in plaque formation of HSV-1 and HSV-2. It also exhibited more potent antiherpetic activity on HSV-1 with 50% effective concentration (EC$_{50}$) of 20.4 $\mu$g/ml than on HSV-2 with EC$_{50}$ of 30.4 $\mu$g/ml. The combined antiherpetic effects of quercitrin with nucleoside antiherpetic agents, acyclovir and vidarabine, were examined on the multiplication of these two strains of herpesviruses in Vero cells by the combination assay. The results of combination assay were evaluated by the combination index (CI) that was calculated by the multiple drug effect analysis. The combinations of quercitrin with acyclovir and vidarabine on HSV-1 showed more potent synergism with CI values of 0.27-0.81 for 50%, 70%, 90% effective levels than those on HSV-2 with CI values of 1.03~2.20..20.

• Korean Journal of Pharmacognosy
• /
• v.30 no.1
• /
• pp.40-47
• /
• 1999

To search for less toxic antiherpetic agents, the inhibitory effects of natural hesperetin on the plaque formation of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in Vero cells were examined by the plaque reduction assay in vitro. Hesperetin inhibited plaque formations of HSV-1 and HSV-2 in a dose dependent manner. It also exhibited more potent antiherpetic activity on HSV-2 with selectivity index (SI) of 9.8 than on HSV-1 with SI of 8.4. The combined antiherpetic effects of hesperetin with nucleoside antiherpetic agents, acyclovir and vidarabine, were examined on the multiplication of these two strains of herpesviruses in Vero cells by the combination assay. The results of combination assay were evaluated by the combination index (CI) that was calculated by the multiple drug effect analysis. The combinations of hesperetin with acyclovir on HSV-1 and HSV-2 showed synergistic effects with CI values of $0.29{\sim}0.73$ for 50%, 70%, 90% effective levels and those with vidarabine showed partially synergistic or additive effects with CI values of $0.83{\sim}1.33$.