Long-Lasting Enhanced Cytokine Responses Following SARS-CoV-2 BNT162b2 mRNA Vaccination

Abstract

The mRNA vaccine against COVID-19 protects against severe disease by the induction of robust humoral and cellular responses. Recent studies have shown the capacity of some vaccines to induce enduring non-specific innate immune responses by the induction of trained immunity, augmenting protection against unrelated pathogens. This study aimed to assess whether the mRNA vaccine BNT162b2 can induce lasting non-specific immune responses in myeloid cells following a three-dose vaccination scheme. In a sample size consisting of 20 healthy individuals from Romania, we assessed inflammatory proteins using the Olink^® Target 96 Inflammation panel, as well as ex vivo cytokine responses following stimulations with unrelated PRR ligands. We assessed the vaccine-induced non-specific systemic inflammation and functional adaptations of myeloid cells. Our results revealed the induction of a stimulus- and cytokine-dependent innate immune memory phenotype that became apparent after the booster dose and was maintained eight months later in the absence of systemic inflammation.

Keywords: cytokine responses; inflammatory responses; innate immune memory; mRNA vaccine; proteomics.

Figure 1

Study design and plasma inflammatory proteomic profiles following BNT162b2 vaccination. (a) Vaccination scheme and timing of plasma and PBMC isolation. (b) The anti-S IgG antibody titers at each timepoint. Individuals who declared a COVID-19 infection prior to inclusion are labeled in red. Vaccination timepoints (D1, D2, BO) and the 8-month mark values were compared to the baseline using the Wilcoxon matched-pairs signed-rank test. Boxplots with a line at the median and the 75th and 25th percentiles; whiskers showing the range of values. (c–f) Volcano plot showing the differences in the proteomic profiles following (c) dose 1 (n = 11), (d) dose 2 (n = 19), (e) booster vaccination (n = 15), and (f) 8 months later (n = 13) compared to baseline. The red dashed line represents the threshold of significance (−log10(0.05)). Nominally significant proteins were labeled. Comparisons were made using the paired multiple t-tests with the FDR (Q = 5%) method of Benjamini and Hochberg for multiple comparisons. BL: baseline, D1: dose 1, D2: dose 2, BO: booster, 8mo: eight months.

Figure 2

Enhanced cytokine production following BNT162b2 vaccination in response to unrelated pathogens. Production of (a) IL-6, (b) IL-1β, (c) IL-1Ra, and (d) TNF-α in PBMCs from healthy volunteers (n = 13) in response to C. albicans, S. aureus, and M. tuberculosis stimulation at baseline, following dose 1, dose 2, the booster dose and 8 months later. Each dot with a line represents an individual sample. Individuals who declared COVID-19 infection prior to inclusion are labeled in red. Paired data were analyzed by comparing each timepoint to the baseline and booster to the eight-month mark. Friedman’s test with Dunn’s correction for multiple comparisons was used. Two-tailed p values < 0.05 are shown. BL: baseline, D1: dose 1, D2: dose 2, 8mo: eight months.