Biology subjects

Bakos, T.

Publications and source records attributed to Bakos, T..

3 recordsLinked to original sources

bioRxiv2025

Acute anaphylactic and multiorgan inflammatory effects of Comirnaty in pigs: evidence of spike protein mRNA transfection and paralleling inflammatory cytokine upregulation

Background and PurposeRare but serious adverse events (AEs) associated with mRNA-lipid nanoparticle (LNP) COVID-19 vaccines, such as Comirnaty and Spikevax, include anaphylaxis and acute multiorgan inflammatory syndrome. The mechanisms of these acute innate immune responses remain poorly understood. This study aimed to investigate these effects using an amplified porcine model. Experimental ApproachNaive and anti-PEG antibody-sensitized pigs were intravenously injected with Comirnaty. Acute anaphylactic responses were assessed through hemodynamic monitoring, hematological changes, and plasma inflammatory markers. Multiorgan inflammatory effects were evaluated by RT-qPCR detection of spike protein (SP) mRNA uptake and inflammatory cytokine gene expression in seven organs over 6 hours. Histopathology and immunohistochemistry were also performed. Key ResultsSevere cardiopulmonary distress developed within minutes of repeated intravenous injections of Comirnaty. RT-qPCR revealed predominant SP mRNA accumulation in liver and PBMCs, with spleen, kidney, lymph nodes, heart, and brain also affected in 40-90% of animals. Repetitive PBMC transfection showed reversible mRNA peaks at 15 minutes, followed by rapid decay. Expression of proinflammatory cytokines (IL-1RA, CXCL10, TNF-, CCL2) paralleled mRNA uptake, suggesting a causal relationship. Cytokine profiles varied by organ (e.g. IL-1RA in kidney, CCL2 in PBMCs). Histologic abnormalities and SP immunopositivity were noted in kidney, heart, and brain. Booster injections replicated PBMC transfection kinetics observed at first dose. Conclusions and ImplicationsThis porcine model reveals systemic anaphylactic reactivity and multiorgan SP mRNA transfection following intravenous injection of mRNA-LNPs, resulting in organ-specific inflammatory responses. These findings provide mechanistic insights into two rare vaccine-related acute AEs and may support future efforts to improve the safety of the mRNA-LNP platform technology.

immunology↗

bioRxiv2024

mRNA-LNP COVID-19 vaccine lipids induce low level complement activation and production of proinflammatory cytokines: Mechanisms, effects of complement inhibitors, and relevance to adverse reactions

Messenger RNA-containing lipid nanoparticles (mRNA-LNPs) enabled widespread COVID-19 vaccination with a small fraction of vaccine recipients displaying acute or sub-acute inflammatory symptoms. The molecular mechanism of these adverse events (AEs) remains undetermined. Here we report that the mRNA-LNP vaccine, Comirnaty, triggers low-level complement (C) activation and production of inflammatory cytokines, which may be key underlying processes of inflammatory AEs. In serum, Comirnaty and the control PEGylated liposome (Doxebo) caused different rises of C split products, C5a, sC5b-9, Bb and C4d, indicating stimulation of the classical pathway of C activation mainly by the liposomes, while a stronger stimulation of the alternative pathway was equal with the vaccine and the liposomes. Spikevax had similar C activation as Comirnaty, but viral or synthetic mRNAs had no such effect. In autologous serum-supplemented peripheral blood mononuclear cell (PBMC) cultures, Comirnaty caused increases in the levels of sC5b-9 and proinflammatory cytokines in the following order: IL-1 < IFN-{gamma} < IL-1{beta} < TNF- < IL-6 < IL-8, whereas heatinactivation of serum prevented the rises of IL-1, IL-1{beta}, and TNF-. Clinical C inhibitors, Soliris and Berinert, suppressed vaccine-induced C activation in serum but did not affect cytokine production when applied individually. These findings suggest that the PEGylated lipid coating of mRNA-LNP nanoparticles can trigger C activation mainly via the alternative pathway, which may be causally related to the induction of some, but not all inflammatory cytokines. While innate immune stimulation is essential for the vaccines efficacy, concurrent production of C- and PBMC-derived inflammatory mediators may contribute to some of the AEs. Pharmacological attenuation of harmful cytokine production using C inhibitors likely requires blocking the C cascade at multiple points.

immunology↗

bioRxiv2022

Zymosan-induced leukocyte and cytokine changes in pigs: a new model for streamlined drug testing against severe COVID-19

Injection of 0.1 mg/kg zymosan in pigs i.v. elicited transient hemodynamic disturbance within minutes, without major blood cell changes. In contrast, infusion of 1 mg/kg zymosan triggered maximal pulmonary hypertension with tachycardia, lasting for 30 min. This change was followed by a transient granulopenia with a trough at 1 h, and then, up to about 6 h, a major granulocytosis, resulting in a 3-4-fold increase of neutrophil-to-lymphocyte ratio (NLR). In parallel with the changes in WBC differential, qRT-PCR and ELISA analyses showed increased transcription and/or release of inflammatory cytokines and chemokines into blood, including IL-6, TNF-, CCL-2, CXCL-10, and IL-1RA. The expression of IL-6 peaked at already 1.5-2.5 h, and we observed significant correlation between lymphopenia and IL-6 gene expression. While these changes are consistent with zymosans known stimulatory effect on both the humoral and cellular arms of the innate immune system, what gives novel clinical relevance to the co-manifestation of above hemodynamic, hematological, and immune changes is that they represent independent bad prognostic indicators in terminal COVID-19 and other diseases involving cytokine storm. Thus, within a 6 h experiment, the model enables consecutive reproduction of a symptom triad that is characteristic of late-stage COVID-19. Given the limitations of modeling cytokine storm in animals and effectively treating severe COVID-19, the presented relatively simple large animal model may advance the R&D of drugs against these conditions. One of these disease markers (NLR), obtained from a routine laboratory endpoint (WBC differential), may also enable streamlining the model for high throughput drug screening against innate immune overstimulation.

immunology↗