Purpose: Respiratory syncytial virus (RSV) is one of the leading causes of severe respiratory disease in infants and adults. While vaccines and monoclonal therapeutic antibodies either are or will shortly become available, correlates of protection remain unclear. For this purpose, we developed an RSV multiplex immunoassay that analyses antibody titers toward the post-F, Nucleoprotein, and a diverse mix of G proteins. Methods: A bead-based multiplex RSV immunoassay was developed, technically validated to standard FDA bioanalytical guidelines, and clinically validated using samples from human challenge studies. RSV antibody titers were then investigated in children aged under 2 and a population-based cohort. Results: Technical and clinical validation showed outstanding performance, while methodological developments enabled identification of the subtype of previous infections through use of the diverse G proteins for approximately 50% of samples. As a proof of concept to show the suitability of the assay in serosurveillance studies, we then evaluated titer decay and age-dependent antibody responses within population cohorts. Conclusion: Overall, the developed assay shows robust performance, is scalable, provides additional information on infection subtype, and is therefore ideally suited to be used in future population cohort studies.

Human microglia are central regulators and actors in brain infections and neuro-inflammatory pathologies. However, access to such cells is limited, and studies systematically mapping the spectrum of their inflammatory states are scarce. Here, we generated microglia-like cells (MGLCs) from human induced pluripotent stem cells and characterized them as a robust, accessible model system for studying inflammatory activation. We validated lineage identity through transcriptome profiling, revealing selective upregulation of microglial signature genes and enrichment of microglia/macrophage-related gene sets. MGLCs displayed distinct morphologies and produced stimulus- and time-dependent cytokine secretion profiles upon exposure to diverse inflammatory stimuli, including pro-inflammatory cytokines (TNFα, interferon-γ) and agonists of the Toll-like receptors TLR2 (FSL-1), TLR3 (Poly(I:C)), TLR4 (lipopolysaccharide, LPS), and TLR7 (imiquimod). Transcriptome profiling and bioinformatics analysis revealed distinct activation signatures. Functional assays demonstrated stimulus-specific engagement of NFκB and JAK-STAT signaling pathways. The shared NFκB nuclear translocation response of TLR ligands and TNFα was reflected in overlapping transcriptome profiles: they shared modules (e.g., oxidative stress response and TNFα-related signaling) identified by weighted gene co-expression network analysis. Finally, the potential consequences of microglia activation for neighboring cells were studied on the example of microglia-astrocyte crosstalk. The capacity of MGLC supernatants to stimulate astrocytes was measured by quantifying astrocytic NFκB translocation. MGLCs stimulated with FSL-1, LPS, or Poly(I:C) indirectly activated astrocytes via a strictly TNFα-dependent mechanism, highlighting the role of soluble mediators in the signal propagation. Altogether, this platform enables a dissection of microglia activation states and multi-parametric characterization of subsequent neuroinflammation.

Background: Emerging immune-evasive viral variants threaten the efficacy of current vaccines, underscoring the need for strategies that elicit broad and durable protection. Heterologous prime–boost regimens combining distinct vaccine platforms can enhance humoral and cellular immunity through complementary mechanisms. Methods: Using an intramuscular immunization scheme aligned with clinical vaccination practice, CD-1 mice received homologous or heterologous prime–boost regimens combining a replication-deficient Orf virus (Parapoxvirus orf, ORFV)-based spike vaccine (ORFV-S) with the licensed adjuvanted recombinant protein vaccine VidPrevtyn Beta. Spike-specific humoral and cellular immune responses were assessed. Results: ORFV-S alone induced potent and broad spike-specific IgG responses and achieved the strongest ACE2-binding inhibition across variants of concern. ORFV-S priming followed by VidPrevtyn Beta boosting markedly enhanced the magnitude and cross-variant breadth of antibody responses compared with homologous protein vaccination. Both homologous ORFV-S and heterologous regimens incorporating ORFV-S elicited strong CD4⁺ and CD8⁺ T-cell responses, whereas VidPrevtyn Beta alone induced only modest T-cell activity, demonstrating that ORFV-S effectively complements protein-based vaccines. Conclusions: The ORFV-S vector represents a potent vaccine platform capable of inducing broad humoral and cellular immunity. Its use in heterologous prime–boost combinations enhances both antibody magnitude and breadth beyond homologous protein vaccination, supporting its application in vaccination strategies against evolving viral pathogens.

Parkinson's disease (PD) is characterized by marked phenotypic heterogeneity particularly with regard to cognitive decline, which may be partly driven by ageing-related molecular pathways. Peroxisome Proliferator-Activated Receptor γ (PPARγ) represents a key downstream component of such pathways, while genetic variation in its coactivator gene peroxisome proliferator-activated receptor γ coactivator-1-α (PPARGC1A) may further modulate disease trajectories. We aimed to investigate the association of cerebrospinal fluid (CSF) PPARγ levels and PPARGC1A single nucleotide polymorphisms (SNPs) with clinical outcomes in PD, METHODS: CSF PPARγ levels were measured in a cohort of 446 with PD, 61 patients with dementia with Lewy Bodies (DLB), and 13 control participants. Associations with clinical parameters were analyzed using cross-sectional and longitudinal approaches. In addition, three PPARGC1A SNPs (rs4697447, rs7659588, rs4697455) were examined for their relationship with cognitive and motor outcomes. Higher CSF PPARγ levels were associated with older age at examination and lower Montreal Cognitive Assessment (MOCA) scores. PPARγ levels differed across diagnostic groups, with highest levels observed in DLB, followed by PD and controls. Elevated PPARγ levels were associated with a higher incidence of cognitive impairment; these associations were largely attenuated after adjustment for age. In exploratory analyses, PPARGC1A variants were associated with cognitive trajectories. CSF PPARγ levels are primarily associated with ageing-related processes rather than reflecting disease-specific effects. Genetic variation in PPARGC1A may contribute to interindividual differences in cognitive progression. Together, these findings support a role of ageing-related pathways in shaping clinical heterogeneity in PD.

Background: Influenza remains a global public health burden. While interpersonal contacts drive transmission, their association with individual-level reinfection risk is not well quantified, particularly in the post-COVID-19 period. We assessed the relationship between contact frequency and serological evidence of influenza reinfection across three consecutive seasons. Methods: In this multicentre, population-based panel study conducted between 2020 and 2024, binding antibody titers against hemagglutinin antigens of three influenza subtypes (A(H1N1), A(H3N2), and B) were measured by a bead-based multiplex immunoassay. Serological evidence of influenza reinfection was defined by fold-changes relative to the preceding season; with adjustments to minimize misclassification due to influenza vaccination. Logistic regression models were designed to estimate crude odds ratios (ORs) and DAG-informed adjusted odds ratios (aORs) for reinfection associated with total, household, and non-household contacts. Results: Serological reinfection was detected in 14% (2021/22), 17% (2022/23), and 12% (2023/24) of participants. Among self-reported unvaccinated participants, reinfection was detected in 6%, 13% and 17% across the respective seasons. Non-household contacts were associated with increased odds of reinfection in one season (2022/23: aOR 1.008, 95% CI 1.002–1.014), while household contacts were associated with higher odds of reinfection in two seasons (2022/23: aOR 1.285, 95% CI 0.905–1.823; 2023/24: aOR 1.267, 95% CI 0.685–2.343). Conclusions: Serological evidence of reinfection among unvaccinated participants in comparison with all participants aligned more closely with surveillance data in 2021/22. Residual misclassification of vaccination or preceding infections may partly explain the absence of an association in 2021/22. Associations between contact behavior and reinfection were season-specific, with household contacts showing the strongest and most consistent effects.