Systemic IL-15, IFN-γ and IP-10/CXCL10 Signature Associated With Effective Immune Response in BNT162b2 mRNA Vaccine Recipients

Early responses to vaccination are important in shaping both humoral and cellular protective immunity. Dissecting innate vaccine signatures may predict immunogenicity and help optimizing efficacy of mRNA and other vaccine strategies. We characterized the cytokine and chemokine responses to the 1st and 2nd dose of the BNT162b2 mRNA (Pfizer/BioNtech) vaccine in antigen-naive vaccine recipients and individuals previously infected by COVID-19 (NCT04743388). Transient increases in IL-15 and IFN-γ levels early after boost correlated with Spike-RBD antibody levels, supporting their possible use as biomarkers of successful vaccination. We identified a systemic signature including IL-15, IFN-γ and IP-10/CXCL10 increase after the 1st vaccination, which was enriched by TNF-α and IL-6 after the 2nd vaccination. In vaccine recipients with history of COVID-19 infection, a single vaccine dose resulted in both strong cytokine induction and antibody titers similar to the ones observed upon booster vaccination in antigen-naive individuals, a result with potential implication for future public health recommendations. Funding Information: Funding: This research was supported [in part] by the Intramural Research Program of the NIH, NCI to G.N.P. and B.K.F. Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: All study procedures were carried out in accordance with the declaration of Helsinki (18th World Medical Association Assembly), its subsequent amendments, the Greek regulations and guidelines, as well as the good clinical practice guidelines (GCP) as defined by the International Conference of Harmonization. The study was also approved by the local ethic committee of Alexandra General Hospital (no 15/23 December 2020).