Spleen tyrosine kinase mediates innate and adaptive immune crosstalk in SARS‐CoV‐2 mRNA vaccination
Sebastian J. Theobald, Alexander Simonis, Julie M Mudler, Ulrike Göbel, Richard Acton, Viktoria Kohlhas, Marie‐Christine Albert, Anna‐Maria Hellmann, Jakob J Malin, Sandra Winter, Michael Hallek, Henning Walczak, Phuong‐Hien Nguyen, Manuel Koch, Jan Rybniker
Abstract
Durable cell-mediated immune responses require efficient innate immune signaling and the release of pro-inflammatory cytokines. How precisely mRNA vaccines trigger innate immune cells for shaping antigen specific adaptive immunity remains unknown. Here, we show that SARS-CoV-2 mRNA vaccination primes human monocyte-derived macrophages for activation of the NLRP3 inflammasome. Spike protein exposed macrophages undergo NLRP3-driven pyroptotic cell death and subsequently secrete mature interleukin-1β. These effects depend on activation of spleen tyrosine kinase (SYK) coupled to C-type lectin receptors. Using autologous cocultures, we show that SYK and NLRP3 orchestrate macrophage-driven activation of effector memory T cells. Furthermore, vaccination-induced macrophage priming can be enhanced with repetitive antigen exposure providing a rationale for prime-boost concepts to augment innate immune signaling in SARS-CoV-2 vaccination. Collectively, these findings identify SYK as a regulatory node capable of differentiating between primed and unprimed macrophages, which modulate spike protein-specific T cell responses.