title: Plaque inhibition assay for drug susceptibility testing of influenza viruses.
abstract: The relative antiviral activities of four drugs against contemporary strains of influenza A and B viruses were determined in Madin-Darby canine kidney cell monolayers with a plaque inhibition assay. This assay proved to be a reliable, rapid method of determining 50% inhibitory concentrations that correlated well with clinically achievable drug levels and the results of clinical trials. Contemporary strains of influenza A viruses (subtypes H1N1, H3N2, HSW1N1) required amantadine hydrochloride and rimantadine hydrochloride 50% inhibitory concentrations in the range of 0.2 to 0.4 microgram/ml, whereas 50% inhibitory concentrations ranged from approximately 50 to 100 micrograms/ml against influenza B viruses. Ribavirin was approximately 10-fold less active than amantadine hydrochloride against influenza A viruses, and the ribavirin 50% inhibitory concentrations against both influenza A and B viruses ranged from 2.6 to 6.8 micrograms/ml. Inosiplex had no antiviral activity in this test system.
mesh_terms: D000547:Amantadine / Q000494:pharmacology; D000998:Antiviral Agents / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D006801:Humans; D007251:Influenza, Human / Q000382:microbiology; D008826:Microbial Sensitivity Tests / Q000379:methods*; D009975:Orthomyxoviridae / Q000187:drug effects*; D012254:Ribavirin / Q000494:pharmacology; D012299:Rimantadine / Q000494:pharmacology; D013997:Time Factors; D010948:Viral Plaque Assay
chemical_list: D000998:Antiviral Agents; D012299:Rimantadine; D012254:Ribavirin; D000547:Amantadine