Biology subjects

Sedlik, C.

Publications and source records attributed to Sedlik, C..

8 recordsLinked to original sources

bioRxiv2026

The differentiation and functional landscape of tumor-resident CD8⁺ T cells shapes immunity and clinical outcomes in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is a common and lethal kidney cancer in which CD8+ T cell-targeted immunotherapies are standard of care. However, tumor CD8+ T cell infiltration correlates with divergent clinical outcomes, reflecting functional heterogeneity. We comprehensively characterized tumor-specific memory CD8+ T cells in ccRCC using phenotypic, transcriptional and functional analyses. Three major subsets were identified based on tissue-residency markers: circulating (Tcirc), tissue-resident (Trm) and CD69+CD103- Trm-like cells, all recognizing autologous RCC cells in an HLA class I-dependent manner. Tcirc cells exhibited greater stemness and cytotoxic potential, whereas Trm populations displayed tissue-residency programs, enhanced tumor reactivity and exhaustion features. Single-cell transcriptomics analyses uncovered substantial heterogeneity within Trm cells, including progenitor, activated, transitional, type-17, interferon-responsive, regulatory and terminally exhausted states. Trajectory and TCR analyses indicated progressive differentiation from central-memory Tcirc cells toward tissue residency while losing circulation, cytotoxicity and stemness potentials and then progress toward terminal exhaustion. Enrichment of progenitor Trm cells associated with improved survival and favorable immunotherapy response, whereas regulatory or exhausted Trm cells correlated with poor outcomes. These findings define the differentiation and functional landscape of tumor-specific CD8+ T cells that shapes immunity and clinical outcomes in ccRCC.

immunology↗

bioRxiv2025

Myeloid reprogramming by poly(I:C) recruits progenitor-exhausted CD8+ T cells and sensitizes rhabdoid tumors to PD-1 blockade

Immune exclusion remains a major barrier to effective immunotherapy in solid tumors. Given the abundance and plasticity of tumor-associated macrophages (TAMs) in many tumors, including pediatric tumors, we investigated whether TLR3 activation could reprogram them to facilitate immune access. Single-cell and spatial profiling in a mouse model of rhabdoid tumors showed that they are dominated by TLR3-expressing TAMs, whose depletion delays tumor growth. Treatment with the TLR3 agonist poly(I:C) promotes immune cell infiltration, including progenitor-exhausted CD8+ T cells, by multiple mechanisms including the reduction and reprogramming of immunosuppressive TAMs, promoting nitric-oxide production by peritumoral macrophages, and inducing CXCL9/10 production. Combined poly(I:C) and PD-1 blockade elicited durable, complete tumor rejection. Human macrophages from tumor biopsies showed conserved TLR3 responsiveness, underscoring translational potential. These findings uncover a mechanism by which TLR3-driven myeloid reprogramming transforms immune-excluded tumors into checkpoint-responsive ones, revealing a therapeutic path to overcome resistance to PD-1 blockade.

immunology↗

bioRxiv2025

Dual PD-L1/TIGIT blockade induces PNAd+ HEV-like vessels and CD62L+ lymphocyte recruitment, driving rhabdoid tumor rejection

Rhabdoid tumors (RTs) are aggressive pediatric malignancies with poor prognosis and limited immunotherapy options. Here, we investigate the therapeutic potential of combined PD-L1 (Programmed cell death ligand 1) and TIGIT (T cell immunoreceptor with Ig and ITIM domains) immune checkpoint blockade in RTs using a preclinical murine model that recapitulates key features of human ATRT (Atypical teratoid rhabdoid tumors) subtypes. Transcriptomic analyses of human and murine RTs reveal co-expression of TIGIT and PD-1 (Programmed cell death 1) pathway components and their ligands, particularly in immune-infiltrated subtypes, supporting a rationale for dual blockade. Combination therapy induces complete tumor regression, prolongs survival, and reprograms the tumor immune microenvironment by enriching CD62L naive and central memory T cells and promoting selective T-cell clonal expansion. Notably, dual blockade initiates PNAd (Peripheral node addressin) high endothelial venule (HEV)-like structures, associated with focal lymphocyte clustering and enhanced immune cell recruitment. These findings reveal a mechanistic link between vascular remodeling and immune infiltration and support dual TIGIT and PD-L1 inhibition as a promising immunotherapeutic strategy for RTs.

immunology↗

bioRxiv2025

Common origin for effector and regulatory Follicular and Tissue-Adapted CD4+ T cells in Non-Small Cell Lung Cancer

Tumor-invaded lymph nodes (LNs) serve as critical hubs for anti-tumor immunity, yet their role in orchestrating immune responses remains poorly understood. Using integrated single-cell RNA sequencing, T cell receptor sequencing, and chromatin accessibility profiling, we analyzed CD4+ T cells from matched blood, tumor-invaded LNs, and tumors of treatment-naive non-small cell lung cancer patients. We identified distinct immunological landscapes across these compartments. Compared to blood, tumor-invaded LNs and tumors were enriched for follicular regulatory T cells (Treg-Tfr), conventional T cell subsets with Tfh-like characteristics (Tconv-Tfh and Tconv-CXCL13), and tissue-resident memory Tregs (Treg-Trm). These populations share a BATF-dependent transcriptional program that governs T-cell activation and tissue adaptation, while simultaneously engaging distinct, subset-specific regulatory networks. Integrative TCR-RNA analysis revealed that tumor-reactive, neoantigen-specific T cell clones were enriched within these subsets and demonstrated extensive LN-tumor clonal sharing, indicating active recirculation between compartments. Through clonal coupling analysis and trajectory inference, we uncovered that Treg-Tfr cells function as multipotent progenitors that bifurcate into tissue-resident Treg-Trm or into ex-Tregs adopting a Tfh-like CXCL13+ ewector phenotype. Remarkably, follicular CD4+ T subsets from LNs and tumor were transcriptionally and epigenetically similar and localized to analogous germinal center niches. These findings establish tumor-invaded LNs as functional extensions of the tumor microenvironment that generate and maintain tumor-reactive CD4+ lineages. The identification of tissue-resident Treg-Tfr plasticity reveals a critical developmental checkpoint that could be therapeutically targeted to redirect immunosuppressive programs toward anti-tumor ewector responses.

immunology↗

bioRxiv2025

A comprehensive analysis of humanized mouse models for the study of cancer immunotherapies

Humanized immune system (HIS) mouse models, generated by engrafting tumors and hematopoietic cells of human (Hu) origin into immunodeficient host mice, effectively recapitulate key aspects of the crosstalk between human immune cells and tumors. These models represent a valuable tool for the preclinical evaluation of immunotherapies. In this study, we provide a comprehensive comparison of two widely used HIS models: the Hu-CD34+ model, which engrafts Hu-hematopoietic cells derived from Hu-CD34+ hematopoietic stem cells (HSCs), and the Hu-PBMC model, which utilizes Hu-peripheral blood mononuclear cells (PBMCs). We assess the kinetics, quality and extent of immune cell engraftment, as well as the development of graft-versus-host disease (GVHD). Additionally, we investigate the impact of different immunodeficient host mouse strains on immune cell reconstitution in the Hu-CD34+ model. Both HIS models were engrafted with human tumors derived from either cell lines or patient-derived xenografts (PDX), revealing distinct immune-tumor interactions that influenced antitumor responses. Notably, tumor responses to T-cell-directed therapies, including anti-PD1 antibodies, IL-2-anti-IL-2 antibody complexes, and T-cell engagers, varied across these models. Our findings provide novel insights into the properties and limitations of HIS models, offering a critical resource for optimizing next-generation immuno-oncology strategies and guiding the design of future therapeutic interventions.

immunology↗

bioRxiv2023

CD39+ conventional CD4+ T cells with exhaustion traits and cytotoxic potential infiltrate tumors and expand upon CTLA-4 blockade

BackgroundConventional CD4+ T (Tconv) lymphocytes play important roles in tumor immunity; however, their contribution to tumor elimination remains poorly understood. MethodsHere we describe a subset of Tconv cells characterized by the expression of CD39. The phenotype, the effector function and transcriptional profile of tumor-infiltrating CD39+ Tconv lymphocytes from different mouse cancer models and breast cancer patients were studied by multiparametric flow cytometry and RNA sequencing. The impact of the in vivo CTLA-4 blockade on the tumor-infiltrating CD39+ Tconv population was assessed in mice grafted with the immunogenic MC38 colorectal tumor. Overall survival was evaluated in a cohort of patients from the TCGA consortium. ResultsIn mouse cancer models, we observed that CD39+ Tconv cells accumulated in tumors as they grew but were absent in lymphoid organs. Compared to tumor CD39- counterparts, CD39+ Tconv cells exhibited a cytotoxic and exhausted signature at the transcriptomic level, confirmed by high protein expression of inhibitory receptors and transcription factors related to the exhaustion phenotype. Additionally, CD39+ Tconv cells showed increased production of IFN gamma, granzyme B, perforin and CD107a expression, but reduced production of TNF. In vivo CTLA-4 blockade induced the expansion of tumor CD39+ Tconv cells, which maintained their cytotoxic and exhausted features. In breast cancer patients, CD39+ Tconv cells were found in tumors and in metastatic lymph nodes but were less frequent in adjacent non-tumoral mammary tissue and not detected in non-metastatic lymph nodes and blood. Human tumor CD39+ Tconv cells constituted a heterogeneous cell population with features of exhaustion, impaired TNF production, and high expression of inhibitory receptors and CD107a. We found that high CD4 and ENTPD1 (CD39) gene expression in human tumor tissues correlated with a higher overall survival rate in breast cancer patients. ConclusionsWe found that CD39 acts as a biomarker of Tconv cells with characteristics of both exhaustion and cytotoxic potential. CTLA-4 blockade expands CD39+CD4+ T cells which may contribute to the reduction of tumor development. Discovering the role of CD39-expressing CD4+ T cells in the tumor microenvironment should help design new strategies to manipulate them and improve the efficacy of current immunotherapies.

immunology↗

bioRxiv2021

Cellular selectivity of STING stimulation determines priming of tumor-specific T cell responses

T cells that recognize tumor antigens are crucial for anti-tumor immune responses. Induction of anti-tumor T cells in immunogenic tumors depends on STING, the intracellular innate immune receptor for cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) and related cyclic dinucleotides (CDNs). However, the optimal way to leverage STING activation in non-immunogenic tumors is still unclear. Here, we show that cGAMP delivery by intra-tumoral injection of virus-like particles (cGAMP-VLP) leads to differentiation of tumor-specific T cells, decrease in tumor regulatory T cells (Tregs) and anti-tumoral responses that synergize with PD1 blockade. By contrast, intra-tumoral injection of synthetic CDN leads to tumor necrosis and systemic T cell activation but no differentiation of tumor-specific T cells, and a demise of immune cells in injected tumors. Analyses of cytokine responses and genetic models revealed that cGAMP-VLP preferentially targets STING in dendritic cells at a 1000-fold less dose than synthetic CDN. Sub-cutaneous administration of cGAMP-VLP showed synergy when combined with a tumor Treg-depleting antibody to elicit systemic tumor-specific T cells, leading to complete and lasting tumor eradication. These finding show that cell targeting of STING stimulation shapes the anti-tumor T cell response and reveal a therapeutic strategy with T cell modulators.

immunology↗

bioRxiv2021

Tissue-resident FOLR2+ macrophages associate with tumor-infiltrating CD8+ T cells and with increased survival of breast cancer patients.

Macrophage infiltration is a hallmark of solid cancers and overall macrophage infiltration is correlated with lower patient survival and resistance to therapy. However, tumor-associated macrophages are phenotypically and functionally heterogeneous. Specific tumor-associated macrophage subsets might be endowed with antagonistic role on cancer progression and on the development of anti-tumor immunity. For instance, monocyte-derived TREM2+ tumor-associated macrophages have pro-tumorigenic and immunosuppressive functions. Here, we identify a discrete population of FOLR2+ tumor-associated macrophages positively correlating with patient survival in breast cancer. FOLR2+ macrophages are evolutionarily conserved across species and populate human and murine healthy mammary gland. Moreover, FOLR2+ macrophages co-localize with lymphoid aggregates containing CD8+ T cells in breast cancer and across ten other types of cancers. This study highlights antagonistic roles for tumor-associated macrophage subsets and paves the way for subset-specific therapeutic interventions in macrophages-based cancer therapies.

immunology↗