A new assay system for guinea pig interferon biological activity.
We have developed an assay system for guinea pig interferon (IFN) based on reduction of viral cytopathic effect (CPE) in various cell lines. CPE inhibition was detected optimally in the guinea pig fibroblast cell line 104C1 infected with encephalomyocarditis virus (EMCV). The amount of biologically active guinea pig IFN was quantified by estimating viable cell numbers colorimetrically by means of a tetrazolium compound, 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium monosodium salt (WST-1) and 1-methoxy-5-methylphenazinium methylsulfate (PMS). WST-1 color developed until stopped by the addition of sulfuric acid. This had no effect on the colorimetric assay, and the color was stable for at least 24 h. The acid also inactivated the EMCV and, thus, eliminated the viral hazard. Inhibition of CPE activity was highly correlated with the concentration of culture supernatants from BCG-vaccinated guinea pig splenocytes stimulated in vitro with tuberculin or an immunostimulatory oligoDNA. This assay detected guinea pig IFN and human IFN-alpha, but not IFN-gamma from human, mouse, rat, pig, or dog. This assay system has proved useful for the titration of guinea pig IFN, being easy to perform, free from viral hazard, relatively species specific, highly reproducible, and inexpensive.
Department of Bacterial and Blood Products, National Institute of Infectious Diseases, Musashimurayama-shi, Tokyo 208-0011, Japan.
Toshiko
T
Yamamoto
Amminikutty
A
Jeevan
Kazue
K
Ohishi
Yasuhiro
Y
Nojima
Kiyoko
K
Umemori
Saburo
S
Yamamoto
David N
DN
McMurray
D000818:Animals; D001500:BCG Vaccine; D001681:Biological Assay / Q000191:economics; D002460:Cell Line; D002470:Cell Survival; D003124:Colorimetry; D004396:Coloring Agents / Q000032:analysis; D017077:Culture Media, Conditioned / Q000494:pharmacology; D003588:Cytopathogenic Effect, Viral / Q000187:drug effects*; D004285:Dogs; D004686:Encephalomyocarditis virus / Q000502:physiology; D005347:Fibroblasts / Q000187:drug effects* / Q000821:virology; D006168:Guinea Pigs / Q000378:metabolism*; D006801:Humans; D016898:Interferon-alpha / Q000032:analysis; D007371:Interferon-gamma / Q000032:analysis; D007372:Interferons / Q000032:analysis* / Q000494:pharmacology; D008773:Methylphenazonium Methosulfate / Q000031:analogs & derivatives* / Q000032:analysis; D051379:Mice; D009838:Oligodeoxyribonucleotides / Q000494:pharmacology; D051381:Rats; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013045:Species Specificity; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000166:cytology; D013464:Sulfuric Acids / Q000494:pharmacology; D013552:Swine; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D013778:Tetrazolium Salts / Q000032:analysis; D014373:Tuberculin / Q000494:pharmacology; D014611:Vaccination; D014721:Vesicular stomatitis Indiana virus / Q000502:physiology
C110656:2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium; D001500:BCG Vaccine; D004396:Coloring Agents; D017077:Culture Media, Conditioned; D016898:Interferon-alpha; D009838:Oligodeoxyribonucleotides; D013464:Sulfuric Acids; D013778:Tetrazolium Salts; D014373:Tuberculin; D008773:Methylphenazonium Methosulfate; C023530:1-methoxy-5-methylphenazinium methyl sulfate; D007371:Interferon-gamma; D007372:Interferons; C033158:sulfuric acid