Targeted Delivery of BZLF1 to DEC205 Drives EBV-Protective Immunity in a Spontaneous Model of EBV-Driven Lymphoproliferative Disease

Abstract

Epstein-Barr virus (EBV) is a human herpes virus that infects over 90% of the world’s population and is linked to development of cancer. In immune-competent individuals, EBV infection is mitigated by a highly efficient virus-specific memory T-cell response. Risk of EBV-driven cancers increases with immune suppression (IS). EBV-seronegative recipients of solid organ transplants are at high risk of developing post-transplant lymphoproliferative disease (PTLD) due to iatrogenic IS. While reducing the level of IS may improve EBV-specific immunity and regression of PTLD, patients are at high risk for allograft rejection and need for immune-chemotherapy. Strategies to prevent PTLD in this vulnerable patient population represents an unmet need. We have previously shown that BZLF1-specific cytotoxic T-cell (CTL) expansion following reduced IS correlated with immune-mediated PTLD regression and improved patient survival. We have developed a vaccine to bolster EBV-specific immunity to the BZLF1 protein and show that co-culture of dendritic cells (DCs) loaded with a αDEC205-BZLF1 fusion protein with peripheral blood mononuclear cells (PMBCs) leads to expansion and increased cytotoxic activity of central-effector memory CTLs against EBV-transformed B-cells. Human–murine chimeric Hu-PBL-SCID mice were vaccinated with DCs loaded with αDEC205-BZLF1 or control to assess prevention of fatal human EBV lymphoproliferative disease. Despite a profoundly immunosuppressive environment, vaccination with αDEC205-BZLF1 stimulated clonal expansion of antigen-specific T-cells that produced abundant IFNγ and significantly prolonged survival. These results support preclinical and clinical development of vaccine approaches using BZLF1 as an immunogen to harness adaptive cellular responses and prevent PTLD in vulnerable patient populations.

Targeted delivery of autoantigen to dendritic cells prevents development of spontaneous uveitis

“…Delivery of fusion proteins in the context of inflammation (e.g. with an adjuvant), promotes immunity and has been applied to promoting protective immunity against infections and cancer ( 20 , 42 – 52 ). In contrast, targeting steady state DC in the absence of additional activation has been used to restore tolerance in autoimmune disease ( 23 , 28 , 29 , 47 , 53 , 54 ).…”

Follicular Helper and Regulatory T Cells Drive the Development of Spontaneous Epstein–Barr Virus Lymphoproliferative Disorder

“…We inoculated PBMCs from EBV+ donors (fifty healthy human volunteers) into CB.17 SCID mice (5 × 10 7 cells per mouse) as described previously [13,26]. Mice injected with human PBMCs were bled every other week.…”

“…Metal-labeled antibodies were purchased or conjugated in-house using the Maxpar antibody conjugation kit per the manufacturer's instructions (Fluidigm, San Francisco, CA, USA) [33]. Cells were stained for the surface and intracellular antibodies as described previously [26]. Before data acquisition, cells were washed once with CSM and twice with sterile water, then resuspended in pure water mixed with 1:20 dilution of 4 elemental mass standard beads (Fluidigm) at 1 mL per million cells.…”

Cancer Vaccines and Immunotherapy for Tumor Prevention and Treatment

“…While vaccine strategies for cancer are inherently more challenging than those against viruses, cancers of viral origin [hepatitis B virus (HBV) and human papillomavirus (HPV)] provide an excellent opportunity for primary cancer prevention through viral-directed vaccines [6,10]. HBV and HPV infection, major viral causes of hepatocellular and cervical cancer, respectively, have been successfully prevented through FDA-approved vaccines [9].…”

“…Vaccines can potentially provide lifelong immunity against infection and can help reduce the significant global burden of these cancers [9]. Complementary to these observations is a study by Ahmed et al showing that the Epstein-Barr virus (EBV) protein BZLF1 may be a good candidate for dendritic cell (DC)-based vaccines in immunosuppressed solid organ transplants recipients with post-transplant lymphoproliferative disease (PTLD) [10]. Despite the success in preventing viral infections through vaccination, there is limited success in developing therapeutic vaccines targeting viral antigens for the treatment of cancers of viral origin.…”