TY - JOUR

T1 - IgG study of blood sera of patients with COVID-19

AU - Kazachinskaia, Elena

AU - Chepurnov, Alexander

AU - Shcherbakov, Dmitry

AU - Kononova, Yulia

AU - Saroyan, Teresa

AU - Gulyaeva, Marina

AU - Shanshin, Daniil

AU - Romanova, Valeriya

AU - Khripko, Olga

AU - Voevoda, Michail

AU - Shestopalov, Alexander

N1 - Funding Information: Author Contributions: Conceptualization, A.S.; methodology, E.K., D.S. (Dmitry Shcherbakov) and A.C.; validation, A.C., A.S. and E.K.; formal analysis, O.K. and D.S. (Daniil Shanshin); investigation, A.C., T.S., Y.K. and V.R.; resources, M.V.; data curation, E.K.; writing—original draft preparation, E.K.; A.C., T.S., Y.K. and V.R.; resources, M.V.; data curation, E.K.; writing—original draft preparation, writing—review and editing, M.G. and E.K.; supervision, M.G. and M.V.; project administration, A.S. E.K.; writing—review and editing, M.G. and E.K.; supervision, M.G. and M.V.; project administra-All authors have read and agreed to the published version of the manuscript. tion, A.S. All authors have read and agreed to the published version of the manuscript. Funding: The reported study was funded by RFBR according to the research project No 20-54-80012. Funding: The reported study was funded by RFBR according to the research project No 20-54-80012. Institutional Review Board Statement: The study was conducted according to the guidelines of the Institutional Review Board Statement: The study was conducted according to the guidelines of the Declaration of Helsinki and approved by the Ethics Committee of the Federal Research Center for Publisher Copyright: © 2021 by the authors.

PY - 2021/11

Y1 - 2021/11

N2 - The COVID-19 pandemic,which began at the end of 2019 in Wuhan, has affected 220 countries and territories to date. In the present study, we studied humoral immunity in samples of the blood sera of COVID-19 convalescents of varying severity and patients who died due to this infection, using native SARS-CoV-2 and its individual recombinant proteins. The cross-reactivity with SARS-CoV (2002) was also assessed. We used infectious and inactivated SARS-CoV-2/human/RUS/Nsk-FRCFTM-1/2020 strain, inactivated SARS-CoV strain (strain Frankfurt 1, 2002), recombinant proteins, and blood sera of patients diagnosed with COVID-19. The blood sera from patients were analyzed by the Virus Neutralization test, Immunoblotting, and ELISA. The median values and mean ± SD of titers of specific and cross-reactive antibodies in blood sera tested in ELISA were mainly distributed in the following descending order: N > trimer S > RBD. ELISA and immunoblotting revealed a high cross-activity of antibodies specific to SARS-CoV-2 with the SARS-CoV antigen (2002), mainly with the N protein. The presence of antibodies specific to RBD corresponds with the data on the neutralizing activity of blood sera. According to the neutralization test in a number of cases, higher levels of antibodies that neutralize SARS-CoV-2 were detected in blood serum taken from patients several days before their death than in convalescents with a ranging disease severity. This high level of neutralizing antibodies specific to SARS-CoV-2 in the blood sera of patients who subsequently died in hospital from COVID-19 requires a thorough study of the role of humoral immunity as well as comorbidity and other factors affecting the humoral response in this disease.

AB - The COVID-19 pandemic,which began at the end of 2019 in Wuhan, has affected 220 countries and territories to date. In the present study, we studied humoral immunity in samples of the blood sera of COVID-19 convalescents of varying severity and patients who died due to this infection, using native SARS-CoV-2 and its individual recombinant proteins. The cross-reactivity with SARS-CoV (2002) was also assessed. We used infectious and inactivated SARS-CoV-2/human/RUS/Nsk-FRCFTM-1/2020 strain, inactivated SARS-CoV strain (strain Frankfurt 1, 2002), recombinant proteins, and blood sera of patients diagnosed with COVID-19. The blood sera from patients were analyzed by the Virus Neutralization test, Immunoblotting, and ELISA. The median values and mean ± SD of titers of specific and cross-reactive antibodies in blood sera tested in ELISA were mainly distributed in the following descending order: N > trimer S > RBD. ELISA and immunoblotting revealed a high cross-activity of antibodies specific to SARS-CoV-2 with the SARS-CoV antigen (2002), mainly with the N protein. The presence of antibodies specific to RBD corresponds with the data on the neutralizing activity of blood sera. According to the neutralization test in a number of cases, higher levels of antibodies that neutralize SARS-CoV-2 were detected in blood serum taken from patients several days before their death than in convalescents with a ranging disease severity. This high level of neutralizing antibodies specific to SARS-CoV-2 in the blood sera of patients who subsequently died in hospital from COVID-19 requires a thorough study of the role of humoral immunity as well as comorbidity and other factors affecting the humoral response in this disease.

KW - Antibody specificity

KW - COVID-19

KW - Recombinant proteins

KW - SARS-CoV-2

KW - Virus neutralization

UR - http://www.scopus.com/inward/record.url?scp=85120357178&partnerID=8YFLogxK

U2 - 10.3390/pathogens10111421

DO - 10.3390/pathogens10111421

M3 - Article

C2 - 34832577

AN - SCOPUS:85120357178

VL - 10

JO - Pathogens

JF - Pathogens

SN - 2076-0817

IS - 11

M1 - 1421

ER -