Longitudinal profile of neutralizing and binding antibodies in vaccinated and convalescent COVID‐19 cohorts by chemiluminescent immunoassays

Abstract

Introduction Surrogate rapid serological assay was urgently demanded for accessibly interpretation of immunity potency and duration of neutralizing antibody against SARS‐CoV‐2. The longitudinal trajectory of antibody profile with a reliable large‐scale assay was crucial to judge the protective immune status, avoid futile therapy and provide insight into the booster vaccination minimizing the risk of COVID‐19. Methods A total of 195 volunteers were enrolled for a two‐doses procedure (0 and 28 days) of inactive vaccination, as well as ten COVID‐19 convalescents. The serum was collected at six time point and detected by chemiluminescent immunoassay with SARS‐CoV‐2 neutralizing antibody (Nab), SARS‐CoV‐2 RBD immunoglobulin G (IgG) antibody (RBD IgG) and RBD total antibody. The diagnostic results and the correlation of antibody level were evaluated among three serological (Nab, RBD IgG, and RBD total antibody) assay, as well as with an authorized cPass kit (Nab). Referred to the assay‐specific threshold, the seroconversion rate and dynamic titer of antibody were exhibited from 0 to 56 days since vaccination. Results There was no difference observed with diagnostic results between neutralizing and RBD IgG antibody (p > 0.05). Both diagnostic results of neutralizing and RBD IgG antibody testing differentiated from RBD total antibody assay (p < 0.05). The coefficient of correlation (R) was above 0.90 among the levels of those three antibodies, more than 0.60 in comparison with neutralizing antibody by cPass enzyme‐linked immunoassay. The “S” varying pattern for various antibodies level was observed with time extension after vaccination. The seroconversion rate was below 11.1% in 2 weeks after the priming dose, while the value climbed to 81% in 1 week after the boosting dose. The seroconversion rate was maintained around 91%. The inactive vaccine elicited 81‐fold higher antibody levels after finished the vaccination schedule than that at the basic point. Besides, the level of neutralizing antibody induced by vaccine was found with a 0.2‐fold ratio by comparison with that in COVID‐19 convalescents. Conclusion The humoral immune response products including SARS‐CoV‐2 neutralizing, RBD IgG antibody and total antibody and the varying pattern of the antibody profile could be rapidly detected by CILA method. Meanwhile, the continuing and dynamic determination was attributed to evaluate the protection effect of humoral immunity against the SARS‐CoV‐2 infection.

Eight Months of Serological Follow-Up of Anti-SARS-CoV-2 Antibodies in France: A Study among an Adult Population

“…This is in agreement with another study, in which most plasmas obtained from individuals recovering from COVID-19 did not contain high levels of neutralizing activity [ 37 ]. In contrast to the finding that vaccination induces the production of abundant neutralizing antibodies, this has been confirmed by a previous study [ 38 ]. The determination of the immune correlates of protection against SARS-CoV-2 is necessary to predict the decrease in antibodies and determine vaccination strategies.…”

Comparison of a rapid fluorescence immunochromatographic test with an enzyme-linked immunosorbent assay for measurement of SARS-CoV-2 spike protein antibody neutralizing activity

“…Several studies show fair agreement between the cPass ELISA method and chemiluminescent immunoassays ( Nandakumar et al, 2021 ),( Nam et al, 2021 ),( Dou et al, 2022 )( Valdivia et al, 2021 ), plaque reduction neutralization tests ( Taylor et al, 2021 ) or other competitive ELISA methods ( Krüttgen et al, 2022 ). Duan et al compared the cPass ELISA method with a dual-detection fluorescence immunochromatographic assay in 266 serum samples, and found fair agreement (Kappa: 0.82, OPA: 91%) ( Duan et al, 2022 ).…”

Response and duration of serum anti‐SARS‐CoV‐2 antibodies induced by the third dose of an inactivated vaccine: A prospective longitudinal cohort study at 21 serial time points over 641 days

“…The invasion of host cells by the virus mainly depends on the RBD of the spike protein 11 . As the gold standard for neutralizing capacity determination, the neutralization assay based on either real virus or pseudovirus is reliable but tedious and time‐consuming 12,13 . The alternative serological test based on RBD–ACE2 interaction has been shown to have high sensitivity and specificity, and a good correlation with the conventional virus neutralization assay 13 .…”

“…The neutralizing antibody is considered critical due to its robust correlation with the protective efficacy of a vaccine, and it has also been reported that specific antibody combinations may contribute to maximum neutralization 14 . Total and IgG antibodies, as two subsets of anti‐COVID‐19 antibodies, also play a role in protecting patients recovering from COVID‐19 from reinfection 12 . Fortunately, the total antibody and IgG antibody maintained high antibody titers and had high seropositive rates of 100% and 90.63%, respectively, which suggested that the anti‐SARS‐CoV‐2 antibodies may still provide a certain degree of protection against infection 1 year after the third dose.…”

“…14 Total and IgG antibodies, as two subsets of anti-COVID-19 antibodies, also play a role in protecting patients recovering from COVID-19 from reinfection. 12 Fortunately, the total antibody and IgG antibody maintained high antibody titers and had high seropositive rates of 100% and 90.63%, respectively, which suggested that the anti-SARS-CoV-2 antibodies may still provide a certain degree of protection against infection 1 year after the third dose. It is noteworthy that different individuals have different immune responses, and the predicted antibody half-lives may be more accurate for explaining the antibody attenuation.…”