Biomedical subjects

Michael Schotsaert

Publications and source records attributed to Michael Schotsaert.

4 recordsLinked to original sources

PubMed2026

Dendritic cells control tertiary lymphoid structure development and maintenance in cancer.

Tertiary lymphoid structures (TLSs) are associated with immunotherapy response, yet the mechanisms controlling their formation and maintenance remain unclear. Using spatial transcriptomics and multiplex imaging across human tumors, we found that CCR7+ mature dendritic cells (DCs) accumulate in TLSs. In a mouse non-small cell lung cancer model that forms mature TLSs, we show that early TLS development requires interferon-γ (IFN-γ)-driven type 1 conventional dendritic cell (cDC1) maturation, migration to tumor-draining lymph nodes (tdLNs), and T cell recruitment. As tumors progress, TLSs persist independently of tdLN T cell egress, coinciding with cDC1 accumulation within intratumoral CCL19 stromal hubs. There, cDC1-major histocompatibility complex class 1 (MHC-I) and -MHC-II concomitant antigen presentation, along with CD40 signaling, sustain TLS, T follicular helper (TFH) cell pool, germinal centers, and tumor-specific immunoglobulin G (IgG). These findings highlight local mature cDC1s as key TLS orchestrators and potential targets to enhance antitumor TLS function.

Animals↗

PubMed2026

Dose-dependent IFN programs in myeloid cells after mRNA and adenovirus COVID-19 vaccination.

BACKGROUNDThe SARS-CoV-2 pandemic provided a rare opportunity to study how human immune responses develop to a novel viral antigen delivered through different vaccine platforms. However, to date, no study has directly compared immune responses to all 3 FDA-approved COVID-19 vaccines at single-cell multiomic resolution.METHODSWe longitudinally profiled SARS-CoV-2-naive adults (n = 31) vaccinated with BNT162b2, mRNA-1273, or Ad26.COV2.S, integrating plasma cytokines, antibody titers, and single-cell multiomic data (DOGMA-Seq).RESULTSWe discovered a distinct, transient IFN program termed ISG-dim, which emerged specifically 1-2 days after the first mRNA dose in approximately 10% of myeloid cells. This state was characterized by ISGF3 complex activation and its target genes (e.g., MX1, MX2, DDX58), with transcriptional and epigenetic profiles distinct from the robust IFN program observed after mRNA boosting or a single Ad26.COV2.S dose (ISG-high). In vitro stimulation of human monocytes showed that IFN-α alone recapitulates ISG-dim, whereas both IFN-α and IFN-γ are required for ISG-high.CONCLUSIONThese findings define dose-dependent IFN programming in human myeloid cells and highlight mechanistic differences between priming and boosting, with implications for optimizing vaccine platform choice, dose scheduling, and formulation.FUNDINGNIH grants AI142086, U19 AI135972, U01 AI165452, U01 AI165452, R01 AI160706, and P30 AG067988.

Humans↗

PubMed2025

Helminth infections affect host immune responses to viral infections and vaccines.

Helminths are highly prevalent in many regions of the world. Due to the chronic nature of most helminth infections, these parasites are proficient immunomodulators of their hosts. This modulation often leads to skewed or even impaired immune responses against unrelated antigens, such as viruses and vaccines, which can be both beneficial and detrimental for the host. The extent of these effects and the impact on the outcomes of viral infection depends on a variety of factors including timing and tropism of both infections, pathological mechanisms, genetic background, and environmental factors. In this review, we dissect these complex interactions between virus and helminths in the context of coinfection and the impact of helminth infection on antiviral vaccine efficacy. We characterize the key contributing mechanisms that have been defined in preclinical models and human trials and describe the immune actors involved in the modulation of the antiviral and vaccine immune response by helminths. Finally, we address the limitations of our current understanding of helminth-virus interactions.

Helminthiasis↗

PubMed2024

Enhanced mucosal SARS-CoV-2 immunity after heterologous intramuscular mRNA prime/intranasal protein boost vaccination with a combination adjuvant.

Current COVID-19 mRNA vaccines delivered intramuscularly (IM) induce effective systemic immunity, but with suboptimal immunity at mucosal sites, limiting their ability to impart sterilizing immunity. There is strong interest in rerouting immune responses induced in the periphery by parenteral vaccination to the portal entry site of respiratory viruses, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), by mucosal vaccination. We previously demonstrated the combination adjuvant, NE/IVT, consisting of a nanoemulsion (NE) and an RNA-based RIG-I agonist (IVT) induces potent systemic and mucosal immune responses in protein-based SARS-CoV-2 vaccines administered intranasally (IN). Herein, we demonstrate priming IM with mRNA followed by heterologous IN boosting with NE/IVT adjuvanted recombinant antigen induces strong mucosal and systemic antibody responses and enhances antigen-specific T cell responses in mucosa-draining lymph nodes compared to IM/IM and IN/IN prime/boost regimens. While all regimens induced cross-neutralizing antibodies against divergent variants and sterilizing immunity in the lungs of challenged mice, mucosal vaccination, either as homologous prime/boost or heterologous IN boost after IM mRNA prime, was required to impart sterilizing immunity in the upper respiratory tract. Our data demonstrate the benefit of hybrid regimens whereby strong immune responses primed via IM vaccination are rerouted by IN vaccination to mucosal sites to provide optimal protection against SARS-CoV-2.

Animals↗