Natural killer cells and BNT162b2 mRNA vaccine reactogenicity and durability

Area of Science:

• Immunology
• Vaccinology

Background:

• Natural killer (NK) cells modulate immune responses to vaccination.
• NK cell activation is observed days after mRNA vaccination.

Purpose of the Study:

• To investigate correlations between baseline NK cell characteristics and immune responses to the Pfizer-BioNTech COVID-19 vaccine (BNT162b2).
• To assess the relationship between NK cells and vaccine-induced inflammatory side effects.

Main Methods:

• Analysis of serum and peripheral blood mononuclear cells (PBMCs) from 188 healthcare workers.
• Quantification of spike-specific IgG antibodies and NK cell phenotype/frequency via flow cytometry.
• Assessment of inflammatory side effects and NK cell functionality via in vitro killing assays.

Main Results:

• NK cells showed activation within a week post-vaccination.
• Higher pre-vaccination NK cell cytotoxicity correlated with increased symptom scores after the first dose.
• Elevated baseline NK cell numbers were linked to lower antibody levels six months post-vaccination.
• NKG2A expression on immature NK cells correlated with enhanced antibody responses.

Conclusions:

• NK cell activation by BNT162b2 vaccination may contribute to inflammatory symptoms.
• Baseline NK cell properties may impact the durability of vaccine-induced antibody responses.