Explore the vast range of titles available.

Tumor-draining lymph node (TDLN) invasion by metastatic cells in breast cancer correlates with poor prognosis and is associated with local immunosuppression, which can be partly mediated by regulatory T cells (Tregs). Here, we study Tregs from matched tumor-invaded and non-invaded TDLNs, and breast tumors. We observe that Treg frequencies increase with nodal invasion, and that Tregs express higher levels of co-inhibitory/stimulatory receptors than effector cells. Also, while Tregs show conserved suppressive function in TDLN and tumor, conventional T cells (Tconvs) in TDLNs proliferate and produce Th1-inflammatory cytokines, but are dysfunctional in the tumor. We describe a common transcriptomic signature shared by Tregs from tumors and nodes, including CD80, which is significantly associated with poor patient survival. TCR RNA-sequencing analysis indicates trafficking between TDLNs and tumors and ongoing Tconv/Treg conversion. Overall, TDLN Tregs are functional and express a distinct pattern of druggable co-receptors, highlighting their potential as targets for cancer immunotherapy. Tumor-draining lymph nodes are often the first site of metastasis in breast cancer patients. Here, the authors show that metastatic lymph nodes are characterized by the accumulation of suppressive regulatory T cells with a distinct phenotype compared to matched non-invaded lymph nodes and tumors.

Personalized cancer vaccines targeting patient-specific neoantigens are a promising cancer treatment modality; however, neoantigen physicochemical variability can present challenges to manufacturing personalized cancer vaccines in an optimal format for inducing anticancer T cells. Here, we developed a vaccine platform (SNP-7/8a) based on charge-modified peptide–TLR-7/8a conjugates that are chemically programmed to self-assemble into nanoparticles of uniform size (~20 nm) irrespective of the peptide antigen composition. This approach provided precise loading of diverse peptide neoantigens linked to TLR-7/8a (adjuvant) in nanoparticles, which increased uptake by and activation of antigen-presenting cells that promote T-cell immunity. Vaccination of mice with SNP-7/8a using predicted neoantigens ( n  = 179) from three tumor models induced CD8 T cells against ~50% of neoantigens with high predicted MHC-I binding affinity and led to enhanced tumor clearance. SNP-7/8a delivering in silico-designed mock neoantigens also induced CD8 T cells in nonhuman primates. Altogether, SNP-7/8a is a generalizable approach for codelivering peptide antigens and adjuvants in nanoparticles for inducing anticancer T-cell immunity. Cancer vaccines that self-assemble into uniform nanoparticles improve tumor clearance.

The induction of an active immune response to control or eliminate tumours is still an unfulfilled challenge. We focused on plasmid DNA vaccines using an innovative approach whereby the antigen is expressed in association with extracellular vesicles (EVs) to facilitate antigen cross-presentation and improve induced immunity. Our two groups had independently shown previously that DNA vaccines encoding EV-associated antigens are more efficient at inducing cytotoxic T-cell responses than vaccines encoding the non-EV-associated antigen. Here, we compared our two approaches to associate the ovalbumin (OVA) antigen to EVs: (a) by fusion to the lipid-binding domain C1C2 of MFGE8(=lactadherin), which is exposed on the surface of secreted membrane vesicles; and (b) by fusion to retroviral Gag capsid protein, which is incorporated inside membrane-enclosed virus-like particles. Plasmids encoding either form of modified OVA were used as DNA-based vaccines (i.e. injected into mice to allow in vivo expression of the antigen associated to EVs). We show that both DNA vaccines induced, with similar efficiency, OVA-specific CD8 + T cells and total IgG antibodies. By contrast, each vaccine preferentially stimulated different isotypes of immunoglobulins, and the OVA-C1C2-encoding vaccine favoured antigen-specific CD4 + T lymphocyte induction as compared to the Gag-OVA vaccine. Nevertheless, both OVA-C1C2 and Gag-OVA vaccines efficiently prevented in vivo outgrowth of OVA-expressing tumours and reduced tumour progression when administered to tumour-bearing mice, although with variable efficacies depending on the tumour models. DNA vaccines encoding EV-associated antigens are thus promising immunotherapy tools in cancer but also potentially other diseases.

IntroductionHumanized 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.MethodsIn 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).ResultsWe 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.DiscussionOur 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.

IntroductionIn human breast cancer, the invasion of tumor-draining lymph nodes (TDLNs) is an important step in disease progression and has predictive value [1]. TDLN dendritic cells (DCs), which are comprised of lymphoid-organ-resident and skin-derived migratory DCs, present tumor antigens to the naïve T cells and induce their activation and polarization into different functional subsets (Th1, Th2, Th17, Th22, Tfh, regulatory T cells) that will lead to antitumor T cell responses or to tolerance [2].ObjectiveSystematic comparison of the immune profile of Invaded (INV) versus Non-invaded (NI) TDLNs would help to identify those immunomodulatory mechanisms associated to the presence of the tumor that could condition the response to immunotherapy.Material and methodsTDLNs from 70 untreated breast cancer patients undergoing surgery at Institut Curie Hospital were obtained in accordance with institutional ethical guidelines. Samples were analyzed by multi-color flow cytometry. For statistical analysis, Wilcoxon matched paired test or Mann-Whitney test was performed using Prism (GraphPadSoftware)ResultsWe studied the distribution of 6 different DC subpopulations and observed in INV TDLNs a significant decrease in the percentage of BDCA1+ DCs (P<0.05) and a significant increase in the percentage of CD11c+HLADR+CD14+cells (P<0.01), including macrophages and inflammatory DCs, compared to NI TDLNs (P<0.05). We also found a significant lower frequency of naïve conventional and regulatory T cells in INV TDLNs (P<0.05). Both, in NI and INV TDLNs, memory conventional and regulatory T cells were highly polarized, mainly to the Th1 phenotype, but also to the Th2, Th17, Tfh and Th22 phenotypes, as determined by the expression of a panel of chemokine receptors and transcription factors. Notably, in INV TDLNs, a significantly higher proportion of regulatory and conventional T cells were Th1-polarized (P<0.05). Further functional analysis showed that after ex-vivo PMA/Iono stimulation, the Th1-polarized conventional T cells, but not the Th1-polarized regulatory T cells produced high amounts of IFN-γ, being the IFN-γ production significantly higher in INV TDLNs (P<0.05).ConclusionOverall, we observed that immune cells from metastatic TDLNs show evidence of high activation (increased proportion of inflammatory DCs and of Th1-polarized memory T cells) highlighting their potential role in the anti-tumor immune response.

Heparan sulfates (HS) are carbohydrate moieties of HS proteoglycans (HSPGs). They often represent alternative attachment points for proteins or microorganisms targeting receptors. HSPGs, which are ubiquitously expressed, thereby participate in numerous biological processes. We previously showed that MHC class II-restricted antigen presentation is increased when antigens are coupled to HS ligands, suggesting that HSPGs might contribute to adaptive immune responses. Here, we examined if HSPG targeting influences other aspects of immune responses. We found that coupling of an HS ligand to the antigen increases antigen presentation to CD4+ and CD8+ T-cells after antigen targeting to membrane immunoglobulins or to MHC-II molecules. Moreover, this increased stimulating capacity correlates with an enhanced CD8+ immune response in mice. Last, animals control more effectively the growth of Ova-expressing tumour cells when they are immunized with an Ova construct targeting HSPGs and MHC-II molecules. Our results indicate that ubiquitous molecules can influence both MHC class I- and MHC class II-restricted antigen presentation and behave as co-receptors during T-cell stimulation. Moreover, they suggest that tumour-antigens endowed with the ability to target both HSPGs and MHC-II molecules could be of value to increase CD8+ immune response and control tumour-growth, opening new perspectives for the design of highly immunogenic protein-based vaccines.

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.