Abstract
Background: Neutralizing antibodies (NAbs) against SARS-CoV-2 infection have a pivotal role in protective immune response; however, their measurement requires specialized facilities. We evaluated the degree of correlation between NAbs and anti-SARS-CoV-2 IgG/total Ig antibodies detected by chemiluminescent immunoassay in asymptomatic and previously symptomatic SARS-CoV-2 patients.
Methods: A total of 1241 participants (previously symptomatic patients and asymptomatic individuals), who were screened for SARS-CoV-2 infection by RT-PCR or serology, were enrolled in our study. Sera were analyzed for the presence of anti-spike-1(S1)-SARS-CoV-2 IgG/total Ig antibodies, using Ortho Clinical Diagnostics, USA. A signal/cut-off value (S/CO) ≥ 1 was considered reactive. NAbs were measured in 103 random samples from groups using microneutralization assay, with titer ≥ 1:10 being considered positive.
Results: Asymptomatic (n = 229) and 261 previously symptomatic individuals with positive serology and negative RT-PCR were finally included. Significant higher anti-S1-IgG titers were seen in asymptomatic individuals (P < 0.0001). Conversely, anti-S1-total Ig titers were significantly higher in previously symptomatic (P < 0.0001). NAbs were detected in both groups, however, higher titers were seen in previously symptomatic patients. There is a correlation between NAbs and both IgG/total anti-S1-SARS-CoV-2 antibodies (r = 0.47, P < 0.0001 and r = 0.49, P < 0.0001, respectively). IgG and total Ig could predict a neutralization titer of ≥ 1:160 at S/CO >4.44 and >65 with AUC 0.69 and 0.67, respectively.
Conclusion: Asymptomatic SARS-CoV-2 infection can produce comparable antibodies response to previously symptomatic individuals, however higher neutralization activity was seen in the previously symptomatic. Anti-S1-SARS-CoV-2 IgG/total Ig antibodies showed a correlation with neutralization activity and can be used to estimate the presence of protective immunity.
Keywords: Asymptomatic; Chemiluminescence; Neutralizing antibodies; Previously symptomatic; SARS-CoV-2.
【저자키워드】 Neutralizing antibodies, SARS-CoV-2., Asymptomatic, chemiluminescence, Previously symptomatic, 【초록키워드】 antibodies, SARS-CoV-2, IgG, serology, antibody, SARS-COV-2 infection, RT-PCR, anti-SARS-CoV-2, immune, Symptomatic patients, Asymptomatic individuals, protective immunity, symptomatic, clinical, chemiluminescent immunoassay, USA, correlation, group, predict, NAb, Protective, microneutralization, SARS-CoV-2 patients, AUC, NAbs, symptomatic individuals, participant, neutralization activity, random, positive, neutralization titer, total Ig, positive serology, negative RT-PCR, asymptomatic individual, reactive, enrolled, analyzed, evaluated, screened, can be used, significantly higher, comparable, were measured, Significant, in both groups, symptomatic individual, symptomatic patient, 【제목키워드】 neutralizing antibody, SARS-CoV-2, coronavirus, Immunoglobulin, chemiluminescence immunoassay, correlation, acute respiratory syndrome,