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\n(COVID-19) has urgently required the development of safe and effective\nvaccines against the severe acute respiratory syndrome coronavirus 2\n(SARS-CoV-2), which is the causative agent of disease. The BNT162b2\n(Pfizer–BioNTech) RNA-based vaccine confers 95% protection against\nCOVID-19 by encoding a mutated isoform of SARS-CoV-2 full-length spike\n(S) protein. Objective: Here, we report the antigen-specific immune\nprofile against SARS-CoV-2 S protein after vaccination with a single\ndose of BNT162b2 in order to define the immunological landscape required\nfor an efficient response to the SARS-CoV-2 vaccine. Methods: We\ndetermined the levels of antibodies and antigen-specific B, T and NK-T\ncells against a recombinant GFP tagged SARS-CoV-2 S protein in subjects\nup to 20 days after injection of a single dose of BNT162b2 vaccine using\na combined approach involving serological assays and flow cytometry\nanalyses. Former COVID-19 patients have been also included in this study\nto evaluate the effect of vaccine after exposition to SARS-CoV-2.\nResults: The level of antigen-specific helper T-cells against SARS-CoV-2\nS protein was reduced in subjects, low responsive or unresponsive to\nvaccination with respect to the highly responsive individuals, while the\nnumbers of antigen-specific regulatory and cytotoxic T-cells were\ncomparable. Of interest, in former COVID-19 patients, a single dose of\nBNT162b2 vaccine induced a significant increase of antibody production\nsimultaneous with an antigen-specific B and NK-T cell response.\nConclusion: Taken together, these results suggest that favorable immune\nprofiles support the progression and an effective reaction to BNT162b2\nvaccination.