scholarly journals PD-1/CTLA-4 Blockade Inhibits Epstein-Barr Virus-Induced Lymphoma Growth in a Cord Blood Humanized-Mouse Model

2016 ◽  
Vol 12 (5) ◽  
pp. e1005642 ◽  
Author(s):  
Shi-Dong Ma ◽  
Xuequn Xu ◽  
Richard Jones ◽  
Henri-Jacques Delecluse ◽  
Nicholas A. Zumwalde ◽  
...  
2018 ◽  
Vol 14 (8) ◽  
pp. e1007221 ◽  
Author(s):  
James C. Romero-Masters ◽  
Makoto Ohashi ◽  
Reza Djavadian ◽  
Mark R. Eichelberg ◽  
Mitch Hayes ◽  
...  

2017 ◽  
Vol 91 (7) ◽  
Author(s):  
Shi-Dong Ma ◽  
Ming-Han Tsai ◽  
James C. Romero-Masters ◽  
Erik A. Ranheim ◽  
Shane M. Huebner ◽  
...  

ABSTRACT Epstein-Barr virus (EBV) infection is associated with B cell lymphomas in humans. The ability of EBV to convert human B cells into long-lived lymphoblastoid cell lines (LCLs) in vitro requires the collaborative effects of EBNA2 (which hijacks Notch signaling), latent membrane protein 1 (LMP1) (which mimics CD40 signaling), and EBV-encoded nuclear antigen 3A (EBNA3A) and EBNA3C (which inhibit oncogene-induced senescence and apoptosis). However, we recently showed that an LMP1-deleted EBV mutant induces B cell lymphomas in a newly developed cord blood-humanized mouse model that allows EBV-infected B cells to interact with CD4 T cells (the major source of CD40 ligand). Here we examined whether the EBV LMP2A protein, which mimics constitutively active B cell receptor signaling, is required for EBV-induced lymphomas in this model. We find that the deletion of LMP2A delays the onset of EBV-induced lymphomas but does not affect the tumor phenotype or the number of tumors. The simultaneous deletion of both LMP1 and LMP2A results in fewer tumors and a further delay in tumor onset. Nevertheless, the LMP1/LMP2A double mutant induces lymphomas in approximately half of the infected animals. These results indicate that neither LMP1 nor LMP2A is absolutely essential for the ability of EBV to induce B cell lymphomas in the cord blood-humanized mouse model, although the simultaneous loss of both LMP1 and LMP2A decreases the proportion of animals developing tumors and increases the time to tumor onset. Thus, the expression of either LMP1 or LMP2A may be sufficient to promote early-onset EBV-induced tumors in this model. IMPORTANCE EBV causes human lymphomas, but few models are available for dissecting how EBV causes lymphomas in vivo in the context of a host immune response. We recently used a newly developed cord blood-humanized mouse model to show that EBV can cooperate with human CD4 T cells to cause B cell lymphomas even when a major viral transforming protein, LMP1, is deleted. Here we examined whether the EBV protein LMP2A, which mimics B cell receptor signaling, is required for EBV-induced lymphomas in this model. We find that the deletion of LMP2A alone has little effect on the ability of EBV to cause lymphomas but delays tumor onset. The deletion of both LMP1 and LMP2A results in a smaller number of lymphomas in infected animals, with an even more delayed time to tumor onset. These results suggest that LMP1 and LMP2A collaborate to promote early-onset lymphomas in this model, but neither protein is absolutely essential.


2020 ◽  
Vol 94 (10) ◽  
Author(s):  
James C. Romero-Masters ◽  
Makoto Ohashi ◽  
Reza Djavadian ◽  
Mark R. Eichelberg ◽  
Mitchell Hayes ◽  
...  

ABSTRACT Epstein-Barr virus (EBV) causes B cell lymphomas and transforms B cells in vitro. The EBV protein EBNA3A collaborates with EBNA3C to repress p16 expression and is required for efficient transformation in vitro. An EBNA3A deletion mutant EBV strain was recently reported to establish latency in humanized mice but not cause tumors. Here, we compare the phenotypes of an EBNA3A mutant EBV (Δ3A) and wild-type (WT) EBV in a cord blood-humanized (CBH) mouse model. The hypomorphic Δ3A mutant, in which a stop codon is inserted downstream from the first ATG and the open reading frame is disrupted by a 1-bp insertion, expresses very small amounts of EBNA3A using an alternative ATG at residue 15. Δ3A caused B cell lymphomas at rates similar to their induction by WT EBV but with delayed onset. Δ3A and WT tumors expressed equivalent levels of EBNA2 and p16, but Δ3A tumors in some cases had reduced LMP1. Like the WT EBV tumors, Δ3A lymphomas were oligoclonal/monoclonal, with typically one dominant IGHV gene being expressed. Transcriptome sequencing (RNA-seq) analysis revealed small but consistent gene expression differences involving multiple cellular genes in the WT EBV- versus Δ3A-infected tumors and increased expression of genes associated with T cells, suggesting increased T cell infiltration of tumors. Consistent with an impact of EBNA3A on immune function, we found that the expression of CLEC2D, a receptor that has previously been shown to influence responses of T and NK cells, was markedly diminished in cells infected with EBNA3A mutant virus. Together, these studies suggest that EBNA3A contributes to efficient EBV-induced lymphomagenesis in CBH mice. IMPORTANCE The EBV protein EBNA3A is expressed in latently infected B cells and is important for efficient EBV-induced transformation of B cells in vitro. In this study, we used a cord blood-humanized mouse model to compare the phenotypes of an EBNA3A hypomorph mutant virus (Δ3A) and wild-type EBV. The Δ3A virus caused lymphomas with delayed onset compared to the onset of those caused by WT EBV, although the tumors occurred at a similar rate. The WT EBV and EBNA3A mutant tumors expressed similar levels of the EBV protein EBNA2 and cellular protein p16, but in some cases, Δ3A tumors had less LMP1. Our analysis suggested that Δ3A-infected tumors have elevated T cell infiltrates and decreased expression of the CLEC2D receptor, which may point to potential novel roles of EBNA3A in T cell and NK cell responses to EBV-infected tumors.


2012 ◽  
Vol 86 (15) ◽  
pp. 7976-7987 ◽  
Author(s):  
S.-D. Ma ◽  
X. Yu ◽  
J. E. Mertz ◽  
J. E. Gumperz ◽  
E. Reinheim ◽  
...  

2020 ◽  
Vol 18 ◽  
pp. 504-524
Author(s):  
Constanze Slabik ◽  
Maja Kalbarczyk ◽  
Simon Danisch ◽  
Reinhard Zeidler ◽  
Frank Klawonn ◽  
...  

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2405-2405
Author(s):  
Renata Stripecke ◽  
Simon Danisch ◽  
Constanze Slabik ◽  
Reinhard Zeidler ◽  
Wolfgang Hammerschmidt ◽  
...  

Abstract INTRODUCTION: A promising rich pipeline of combination therapies targeting checkpoint molecules expressed on T cells and/or tumor cells is currently being developed to abrogate tumor-induced immunosuppression. Novel in vivo models suitable for validating these immunotherapies and predict safety issues are warranted to accelerate their translation to patients. AIM: Epstein Barr virus (EBV) is a type 1 carcinogen that is directly associated with the development of human B cell neoplasms. We modelled EBV infection and tumor progression in long-term humanized mice and investigated the activation of T cells with PD-1 expression. Further, we performed studies evaluating the effects of an anti-PD-1 antibody (pembrolizumab/ keytruda) in on EBV infections and/or tumor growth. METHODS: Humanized mice transplanted with human cord-blood CD34+ stem cells and showing long-term (15 weeks) human T cell reconstitution were infected with an oncogenic recombinant Epstein Barr Virus (EBV), encoding enhanced firefly luciferase (fLuc) and green fluorescent protein (GFP). EBV infections were monitored by optical imaging analyses and PCR. CD8+ and CD4+ T cell subtypes (PD-1+, naïve, central memory, effector memory and terminal effector) were sequentially monitored in blood by longitudinal flow cytometry analyses and in organs at experimental endpoint. Histopathological analyses were performed to characterize EBV infection (EBER+) and PD-1+ T cell-rich infiltrates in tissues and tumors. We used the model to evaluate the effects of pembrolizumab administered after EBV challenge at low dose (first dose 1.65mg/kg and then 3.30 mg/kg, every other week, n=3) or high dose (first dose 5.00 mg/kg and then 10.00 mg/kg every other week, n=3) in respect to EBV infected controls (n=2). RESULTS: EBV-fLuc was detectable one week after infection by non-invasive optical imaging in the spleen, from where it spread rapidly and systemically. Among the EBV-infected mice, 8/18 (=44%) developed macroscopically visible tumors in the spleen. For further analyses of the data, we then compared EBV-infected mice with ("EBV-Tumor") or without ("EBV") macroscopic tumors. At 6 weeks post-infection, the relative CD8+ T cell frequencies increased significantly and constantly (control Vs. EBV p=0.0021, control Vs. EBV-Tumor p=<0.0001, EBV Vs. EBV-Tumor p=0.0072). For absolute cell counts in tissues, CD8+ T cell increases were more dramatic in mice infected with EBV and developing tumors. These differences amounted to approximately tenfold relative to controls and 3-fold relative to mice not developing tumors. Mice infected with EBV showed 90-100% of the CD4+ and CD8+ T cells in lymphatic tissues expressing PD-1. Mice with EBV-tumors showed twice as many PD-1+ CD4+ and three times as many PD-1+ CD8+ T cells as infected mice without tumors. Histopathology combined with EBER in situ hybridization, showed foci of EBV infected cells in close association with PD-1+ infiltrating lymphocytes, often in perivascular regions. This model was then used to evaluate dose-dependent effects of pembrolizumab. The check-point inhibitor controlled EBV-fLUC spread for 2 weeks, but later prompted increased levels of infections. At endpoint analyses, mice receiving pembrolizumab showed larger dissemination of tumors. CONCLUSIONS: We are currently performing additional experiments in order to elucidate this mechanism of EBV rebound. This humanized mouse model contributes to risk assessment prior to clinical trials of the use of checkpoint inhibitors in patients after transplantations at high risk of EBV infections. Disclosures Ganser: Novartis: Membership on an entity's Board of Directors or advisory committees.


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