Spike-specific immune response induced by BNT162b2 mRNA vaccine in
former COVID-19 patients and high responsive subjects
Abstract
Background: The worldwide escalation of Coronavirus Disease 2019
(COVID-19) has urgently required the development of safe and effective
vaccines against the severe acute respiratory syndrome coronavirus 2
(SARS-CoV-2), which is the causative agent of disease. The BNT162b2
(Pfizer–BioNTech) RNA-based vaccine confers 95% protection against
COVID-19 by encoding a mutated isoform of SARS-CoV-2 full-length spike
(S) protein. Objective: Here, we report the antigen-specific immune
profile against SARS-CoV-2 S protein after vaccination with a single
dose of BNT162b2 in order to define the immunological landscape required
for an efficient response to the SARS-CoV-2 vaccine. Methods: We
determined the levels of antibodies and antigen-specific B, T and NK-T
cells against a recombinant GFP tagged SARS-CoV-2 S protein in subjects
up to 20 days after injection of a single dose of BNT162b2 vaccine using
a combined approach involving serological assays and flow cytometry
analyses. Former COVID-19 patients have been also included in this study
to evaluate the effect of vaccine after exposition to SARS-CoV-2.
Results: The level of antigen-specific helper T-cells against SARS-CoV-2
S protein was reduced in subjects, low responsive or unresponsive to
vaccination with respect to the highly responsive individuals, while the
numbers of antigen-specific regulatory and cytotoxic T-cells were
comparable. Of interest, in former COVID-19 patients, a single dose of
BNT162b2 vaccine induced a significant increase of antibody production
simultaneous with an antigen-specific B and NK-T cell response.
Conclusion: Taken together, these results suggest that favorable immune
profiles support the progression and an effective reaction to BNT162b2
vaccination.