Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)–Specific T Cells and Antibodies in Coronavirus Disease 2019 (COVID-19) Protection: A Prospective Study

Abstract

Background During the ongoing coronavirus disease COVID-19 pandemic, many individuals were infected with and have cleared the virus, developing virus-specific antibodies and effector/memory T cells. An important unanswered question is what levels of T cell and antibody responses are sufficient to protect from the infection. Methods In 5340 Moscow residents, we evaluated anti-SARS-CoV-2 IgM/IgG titers and frequencies of the T cells specific to the membrane, nucleocapsid, and spike proteins of SARS-CoV-2, using IFNγ ELISpot assay. Additionally, we evaluated the fractions of virus-specific CD4+ and CD8+ T cells using intracellular staining of IFNγ and IL2 followed by flow cytometry. We analyzed the COVID-19 rates as a function of the assessed antibody and T cell responses, using the Kaplan-Meyer estimator method, for up to 300 days post-inclusion. Results We showed that T cell and antibody responses are closely interconnected and are commonly induced concurrently. Magnitudes of both responses inversely correlated with infection probability. Individuals positive for both responses demonstrated the highest levels of protectivity against the SARS-CoV-2 infection. A comparable level of protection was found in individuals with antibody response only, while the T cell response by itself granted only intermediate protection. Conclusions We found that the contribution of the virus-specific antibodies to protection against the SARS-CoV-2 infection is more pronounced than that of the T cells. The data on the virus-specific IgG titers may be instructive for making decisions in personalized health care and public anti-COVID-19 policies.

Enhanced SARS-CoV-2 IgG durability following COVID-19 mRNA booster vaccination and comparison of BNT162b2 with mRNA-1273

“… 6 , 7 , 8 Although antibody levels are an imperfect surrogate of vaccine efficacy, it is clear that antibodies to S-RBD are an important component of a protective response. 1 , 2 To date there has been little data showing the dynamics of the antibody response after booster vaccination in comparison to the initial primary series. In addition, there has been a lack of head-to-head studies comparing BNT162b2 and mRNA-1273 after booster vaccination.…”

Integrated SARS-CoV-2 serological and virological screening across an acute fever surveillance platform to monitor temporal changes in anti-spike antibody levels and risk of infection during sequential waves of variant transmission — Dominican Republic, March 2021 to August 2022

“…These findings suggest that binding antibodies, at least total anti-S antibodies as measured in this study, track with functional measures of immunological protection such as viral neutralization, Fc-function, and potentially T cell responses, as previously reported. 19–21 Our findings suggest that while likely inappropriate for adjudicating vaccine efficacy and vaccine approval, total SARS-CoV-2 binding antibodies are reasonable surrogate markers of immunological protection against infection, including infection by emerging strains with substantial immune-evasion capacity. Given the relative simplicity, high throughput capacity, and cost-effectiveness of measuring anti-S antibodies versus live or pseudoviral neutralizing activity, this approach may be suitable for characterizing population level immunological protection, parameterizing transmission and prediction models and, in turn, informing national and regional public health policy.…”

“…These findings suggest that binding antibodies, at least total anti-S antibodies as measured in this study, track with functional measures of immunological protection such as viral neutralization, Fc-function, and potentially T cell responses, as previously reported. 19–21 Our findings suggest that while likely inappropriate for adjudicating vaccine efficacy and vaccine approval, total SARS-CoV-2 binding antibodies are reasonable surrogate markers of immunological protection against infection, including infection by emerging strains with substantial immune-evasion capacity.…”

Long-term immunological consequences of anti-CD20 therapies on humoral responses to COVID-19 vaccines in multiple sclerosis: an observational study

“… 7 , 15 It has become clear that anti-CD20 substances blunt humoral responses to pathogen-specific vaccines. 11 – 13 Given evidence of pathogen-specific neutralizing antibodies inhibiting severe SARS-CoV-2 infections and humoral immunity to be more relevant than T-cell responses for successful COVID-19 control, 16 – 18 we investigated the duration of the anti-CD20 treatment-induced negative effect on humoral responses to COVID-19 vaccines. At a median of 26 months after last anti-CD20 infusion, COVID-19 vaccines elicited significantly higher antibody levels compared with patients with ongoing anti-CD20 therapy, indicating that the inhibiting effect on humoral responses to vaccines is transient.…”