Adaptation of the MTT assay for detection of neutralizing antibodies against the SARS-CoV-2 virus

Introduction. The ability of SARS-CoV-2 antibodies to neutralize the virus is primary indicator their specific activity. test for neutralizing (NAbs) much needed in different biomedical studies.The aim study find optimum conditions microscopic and spectrophotometric detection SARSCoV-2 NAbs by inhibition cytopathic effect (CPE) cell cultures.Materials methods. Blood sera collected from COVID-19 convalescent patients healthy individuals (n = 96) were tested using ELISA method. coronavirus, Dubrovka strain (GenBank accession no. MW514307.1) was grown culture medium Vero line CCL-81 (ATCC). Real-time RT-PCR, ELISA, Sanger sequencing used virus. results neutralization (NT) assessed through examination CPE methyl thiazolyl tetrazolium (MTT) assay.Results. isolated a patient adapted grow culture. At low dose infection (MOI 0.00001), caused pronounced with viability less than 3%, thus making it possible assess NT inhibition. ELISA-based comparative showed positive correlation between NAb titers Nab S-protein RBD (Spearman’s r 0.714; p 0.001). (the MTT assay) also demonstrated 0.963; 0.05).Conclusion. served develop titer assessment system, which can be both studies an assay studies. provides automated reading results, optimizes statistical analysis obtained data, minimizes subjectivity results. Being vital dye, penetrates only viable cells, contributing reliability compared other dyes.