Germinal centers (GCs) are transient microanatomical structures that coordinate humoral immune responses through dynamic interactions between antigen presenting cells, T follicular helper cells, and B cells. Despite their central importance to immune protection, GC human biology remains difficult to interrogate due to significant inter-species variability, limited experimental accessibility to primary human tissues, and high interindividual variability. We developed a human immune culture platform that supports spontaneous multicellular organization of human peripheral blood mononuclear cells derived from primary CD19+ B cells, memory CD4+ T cells, and monocyte-derived dendritic cells into Germinal Center-like Organoids (GCLOs). These bioengineered GCLOs self-organize into stable clusters that exhibit stimulus and donor dependent differences in cellular composition and function. We observed the emergence of GC-like T and B cell subsets, functional IgG output, and the appearance of plasmablast-like populations. Notably, the age of the donors and the type of stimuli influenced GCLOs architecture, immune subsets, and antibody output. Platform outputs showed correspondence with clinical vaccine responsiveness across human donors, capturing inter-individual differences in humoral GCLO immune responses to the flu vaccine, including age-associated trends consistent with immunosenescence. This platform allows scalable investigation of human GC-associated immune features and provides a tractable framework for studying donor heterogeneity in humoral immunity.

Asthma is a deadly chronic respiratory disease affecting over 300 million people. While allergen immunotherapy remains the only disease-modifying treatment, it is poorly applicable for patients with severe asthma. Here, we explored the therapeutic potential of regulatory T cells (Tregs) armed with chimeric allergen receptors-named CAlleR-redirected against the major allergen of birch pollen Bet v1. Four novel anti-Bet v1 antibodies were identified and used to engineer and functionally validate CAlleR. CAlleR Tregs showed specific in vitro activation and suppression and significantly reduced the airway hyperresponsiveness in birch pollen-sensitized mice. Mechanistically, CAlleR Tregs migrated to the lungs and mediastinal lymph nodes, interacted with CD11c+ dendritic cells, and were activated in a FcγR-dependent manner by cross-presenting Bet v1 stabilized with noncompetitive anti-Bet v1 antibodies. These findings unveil a novel mechanism for targeting soluble antigens and highlight the potential of CAlleR Tregs to prevent and treat severe allergies.

BackgroundHigh densities of tertiary lymphoid structures (TLSs) are associated with improved clinical outcomes in various malignancies, including human papillomavirus (HPV)-associated head and neck squamous cell carcinoma (HNSCC). However, the role of TLSs in shaping antitumor immunity in HPV-induced cervical cancer (CESC) remains unclear. Therefore, we analyzed the density, composition, and prognostic impact of TLSs in patients with CESC as well as patients with HNSCC.MethodsMultiplex immunofluorescence, immunohistochemistry, and spatial transcriptomics were used to analyze TLS density and composition in HNSCC and CESC tissue sections with respect to patient prognosis. The spatial approach was supplemented by flow cytometry-based analysis of the polymorphonuclear myeloid-derived suppressor cell (PMN-MDSC) phenotype in freshly resected primary tumor tissues.ResultsAlthough both indications were associated with HPV infection, we confirmed a positive correlation between TLS density and improved overall survival only in patients with HNSCC. The TLS composition differed markedly between HNSCC and CESC samples, with a shift toward high regulatory T cell (Treg) and PMN-MDSC abundance in CESC samples. The highest Treg and PMN-MDSC levels were observed in patients with CESC who died of the disease. CESC-infiltrating PMN-MDSCs showed high arginase 1 expression, which correlated with diminished T-cell receptor (TCR)ζ chain expression in CESC-infiltrating T cells. Additionally, the high number of PMN-MDSCs in TLSs was associated with the absence of HPV-specific T cells in CESC.ConclusionsUnlike in HNSCC, the composition of TLSs, rather than their quantity, was associated with the overall survival of patients with CESC. High numbers of Tregs and PMN-MDSCs infiltrating immature TLSs prevail in patients with CESC who succumbed to the disease and seem to affect tumor-specific immune responses.