ABSTRACT
Under conditions of COVID-19 pandemic, considerable amounts of SARS-CoV-2 contained in household, municipal, and medical wastewaters inevitably reach natural water bodies. Possible preservation of virus infectivity in liquid environment is of a paramount epidemiological importance. Experiments demonstrated that SARS-CoV-2 is resistant to multiple freezing/thawing cycles and retains its infectivity in tap and river water for up to 2 days at 20°C and 7 days at 4°C. In natural milk, its viability is preserved in a refrigerator for 6 days. The exposure of aquarium fish to the virus-containing water fails to cause any infection.
Subject(s)
COVID-19 , Animals , Humans , Pandemics , SARS-CoV-2 , Wastewater , WaterABSTRACT
Different methods for producing bulk quantities of concentrated and purified SARS-CoV-2 for the use as antigens and for the research into COVID-19 biology were tested.
Subject(s)
COVID-19 Testing/methods , COVID-19/diagnosis , SARS-CoV-2/immunology , Viral Load/immunology , Virion/immunology , Animals , Antibodies, Neutralizing/isolation & purification , Antibodies, Neutralizing/metabolism , Antibodies, Viral/isolation & purification , Antibodies, Viral/metabolism , COVID-19/virology , Cell Line , Chlorocebus aethiops , Convalescence , Epithelial Cells/virology , Humans , Immune Sera/chemistry , SARS-CoV-2/genetics , SARS-CoV-2/growth & development , Swine , Vero Cells , Viral Load/genetics , Viral Proteins/immunology , Viral Proteins/isolation & purification , Viral Proteins/metabolism , Virion/genetics , Virion/growth & development , Virus ReplicationABSTRACT
Objective: isolation of coronavirus SARS-CoV-2 from clinical sample of patient with COVID-19 in Novosibirsk;obtaining a purified and inactivated viral antigen and study of its antigenic properties. Materials and methods: virus isolation was carried out in Vero cell culture from nasopharyngeal swab positive on SARS-CoV-2 RNA. The efficiency of SARS-CoV-2 replication in cell culture was assessed on the appearance of cytopathic effect (CPE) and the presence of viral RNA in cultural medium with reverse transcription – polymerase chain reaction (RT-PCR). Purification, concentration and inactivation of the viral preparation were carried out according to standard methods. The purity of the purified preparation and the profile of viral proteins were determined by electrophoresis in 10% polyacrylamide gel (PAG) with the addition of sodium dodecyl sulfate (SDS). The presence and specificity of viral proteins were detected using COVID-19 convalescent’s sera with enzyme-linked immunosorbent assay (ELISA) and immunoblotting. Results: SARS-CoV-2/human/ RUS/Nsk-FRCFTM-1/2020 isolate was obtained after passage on Vero cells from a virus-containing clinical sample. A purified, concentrated, inactivated, whole-virion antigen was obtained. It contains three structural proteins: glycoprotein S (approximately 200 kDa), nucleoprotein N (48 kDa), and matrix protein M (20-25 kDa). All viral proteins were detected with serum antibodies of COVID-19 convalescents. Conclusion: SARS-CoV-2 coronavirus can be isolated in Vero cell culture. The antigenic specificity of the three structural viral proteins (S, N, and M) is preserved in the purified inactivated viral preparation. The inactivated whole-virion antigen of SARS-CoV-2/human/RUS/Nsk-FRCFTM-1/2020 isolate can be used to study the antigenic immunomodulating properties of viral proteins, to obtain immune sera of laboratory animals, and also as a component of test systems for the detection of specific antibodies with ELISA and immunoblotting.