Leoncini, L. | Search bioRxiv

bioRxiv2026

Loss of systemic anti-viral immunity and LMP1-driven suppressive myeloid tumour niches converge to shape the immunobiology of EBV+ diffuse large B-cell lymphoma

Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma (EBVDLBCL) is an aggressive lymphoma with poor outcomes and an incompletely understood pathogenesis, frequently attributed to immunosenescence. However, its occurrence across all age groups suggests alternative mechanisms. Here, we integrate functional profiling of peripheral antiviral T-cell immunity with high-dimensional spatial proteomics and mechanistic in vitro modelling to define the immunological landscape of EBVDLBCL. We show that both EBV and EBV-DLBCL patients exhibit broad impairments in antiviral T-cell responses compared with healthy controls, affecting latent and lytic EBV antigens as well as non-EBV viral targets, with deficits most pronounced in EBV patients. Spatial proteomic analysis revealed that EBVDLBCL harbours a profoundly immunosuppressive tumour microenvironment characterised by relative loss of intratumoural CD8 T cells, expansion of PD-1 regulatory and exhausted T-cell populations, and dense aggregates of PD-L1/IDO1 macrophages. Compared with EBV classical Hodgkin lymphoma and infectious mononucleosis, EBV DLBCL displayed the most marked macrophage-associated immunosuppressive signature and the lowest T-cell density. Suppressive myeloid niches were preferentially enriched around LMP1-expressing tumour cells, a feature not observed in the other EBV-associated conditions. Together, these findings indicate that EBVDLBCL is driven by the convergence of systemic antiviral immune dysfunction and an LMP1-dependent suppressive tumour microenvironment.

cancer biology↗

bioRxiv2018

Interplay between the epigenetic enzyme lysine (K)-specific demethylase 2B and Epstein-Barr virus infection.

Histone modifier lysine (K)-specific demethylase 2B (KDM2B) plays a role in hematopoietic cells differentiation and its expression appears to be deregulated in certain cancers of hematological and lymphoid origins. We have previously found that KDM2B gene is differentially methylated in cell lines derived from the Epstein-Barr virus (EBV) associated endemic Burkitts lymphomas (eBL) compared to EBV negative sporadic BL cells. However, whether KDM2B plays a role in eBL development has never been previously demonstrated. Oncogenic viruses have been shown to hijack the host cell epigenome to complete their life cycle and to promote the transformation process by perturbing cell chromatin organization. Here we investigated whether EBV would alter KDM2B levels to enable its life cycle and promote B-cells transformation. We show that infection of B-cells with EBV leads to down-regulation of KDM2B levels. We also show that LMP1, one of the main EBV transforming proteins, induces increased DNMT1 recruitment to KDM2B gene and augments its methylation. By altering KDM2B levels and performing chromatin immunoprecipitation in EBV infected B-cells, we were able to show that KDM2B is recruited to the EBV gene promoters and inhibits their expression. Furthermore, forced KDM2B expression in immortalized B-cells led to altered mRNA levels of some differentiation-related genes. Our data show that EBV deregulates KDM2B levels through an epigenetic mechanism and provide evidence for a role of KDM2B in regulating virus and host cell gene expression, warranting further investigations to assess the role of KDM2B in the process of EBV-mediated lymphomagenesis.\n\nIMPORTANCE. In Africa, Epstein-Barr virus infection is associated with endemic Burkitt lymphoma, a pediatric cancer. The molecular events leading to its development are poorly understood compared to the sporadic Burkitt lymphoma. In a previous study, by analyzing the DNA methylation changes in endemic compared to sporadic Burkitt lymphomas cell lines, we identified several differential methylated genomic positions in proximity of genes with a potential role in cancer, among them the KDM2B gene. KDM2B encodes a histone H3 demethylase already shown to be involved in some hematological disorders. However, whether KDM2B plays a role in the development of Epstein-Barr virus-mediated lymphoma has never been investigated before. In this study we show that Epstein-Barr virus deregulates KDM2B expression and describe the underlying mechanisms. We also reveal a role of the demethylase in controlling viral and B-cells genes expression, thus highlighting a novel interaction between the virus and the cellular epigenome.

microbiology↗