A METHOD FOR ANALYSING A SAMPLE FOR THE PRESENCE OF A BIOLOGICAL SUBSTANCE, ESPECIALLY A VIRUS, USE OF THE METHOD FOR QUANTITATIVE DETERMINATION OF BIOLOGICAL SUBSTANCES AND AGENTS FOR USE IN AS WELL AS NOVEL SUBSTANCES DETECTED BY THE METHOD

摘要

A method for analysing a sample for the presence of a biological substance, especially a virus, is based upon an intact dehydrogenase enzyme system in living cells (including bacteria), which will normally convert a tetrazolium salt, preferably MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide), to a coloured formazan complex which in turn, can be detected spectrophotometrically. Virus will also affect the MTT-system of the appropriate target cells by causing a dramatic drop in the normal production of the said coloured compounds compared to non-infected control cell cultures. Substances interfering with the virus system, the so-called antiviral agents, will cause a protection of the cells reflected in an almost unchanged or only slightly reduced colour production. Substances having a toxic influence on human beings or cells can be detected irrespectively of their origin. Among the biological substances which can be detected by the present method is an antiviral factor of particular interest present in new born calf serum (NBS). The method is also suited for screening and/or determining of interferons.