A Novel Haplo-Identical Adoptive CTL Therapy As Treatment For EBV-Associated Lymphoma After Stem Cell Transplantation

Abstract

We have developed a cancer vaccine in which autologous myeloma cells are fused with dendritic cells (DCs) resulting in the presentation of tumor antigens in the context of DC mediated costimulation. In animal models, vaccination with fusion cells results in eradication of established tumor, and in clinical trials, both immunologic and clinical responses have been observed. However, response to vaccination may be muted by inhibitory signals such as the PD1/PDL1 pathway which blunt activated T cell responses. In this study, we evaluated expression of PD1 on T cells derived from patients with multiple myeloma (MM), and PDL1 expression on primary myeloma cells and DC/MM fusions. We evaluated the effect of PD-1 blockade on T cell response to DC/MM fusion cell vaccination in vitro. Tumor cells were obtained from bone marrow aspirates of MM patients. Nonadherent peripheral blood mononuclear cells (PBMCs) obtained from patients with MM and normal volunteers were cultured in RPMI supplemented with 10U/ml IL-2, and expression of PD-1 on CD4 + T cells was assessed by flow cytometry. DCs were generated from adherent PBMCs cultured with rhIL-4, GM-CSF and TNFa and fused with MM cells by coculture in 50% solution of PEG. T cells were stimulated by DC/MM fusions in the presence or absence of PD-1 blockade. We demonstrate that PD-1 expression is markedly upregulated on T cells in patients with advanced MM. As compared to a control population in which mean levels of PD-1 expression was 6% (n 5 7), mean expression in patients with MM was 20% (n 5 9). Mean expression of PDL-1 was 66% on patient derived MM cells (n 5 3) and. 90% on DC/MM fusions (n 5 2), which potentially provides an inhibitory signal dampening fusion mediated immunologic response. We examined the effect of PD-1 blockade on T cell response to DC/MM fusions ex vivo. Enhanced fusion mediated stimulation of T cells was noted in the presence of anti-PD-1, resulting in a greater than 5 fold increase in T cell proliferation. Interferon gamma secretion by CD4 + T cells in response to stimulation by DC/MM fusions increased from 4% to 11% in the presence of PD1 blockade, while IL-10 secretion decreased from 6.5% to 3.5%. In summary, we demonstrate that PD-1 expression is increased in T cells of MM patients, and PD-1 blockade enhances activated T cell responses following stimulation with a DC/MM fusion vaccine. A clinical trial in which MM patients are treated with DC/MM fusions in conjunction with anti-PD1 is planned.

EBV-induced post transplant lymphoproliferative disorders: a persisting challenge in allogeneic hematopoetic SCT

“…A CR was achieved in one exemplary case. 40 The occurrence of EBV-PTLD in recipients of allogeneic cord blood units represents a further challenge as the donor is usually not available. Therefore, alternative T-cell sources with at least a single match in one HLA-class I loci (for example, HLA-A201) are required.…”

Umbilical cord blood graft engineering: challenges and opportunities

“…88,89 Rapid isolation strategies such as 'gamma catch' can be utilized when VSTs occur at high frequency in the donor's blood. This strategy has been successfully used in patients with CMV disease or viremia, with a response rate of 83%, 90 EBV, with a response rate of 50-70% 91,92 and ADV, with responses in 5 of 6 patients in a small study.…”

Immunotherapy against cancer-related viruses

“…Over the past 20 years, major improvements have been made to the manufacture and processing of these EB-VSTs, many of which have also facilitated the manufacture of T cells directed to other oncogenic viruses (see HPV below) [11,[53][54]. In early studies, EBV-transformed B-lymphoblastoid cell lines (LCLs), which express the same viral antigens as Latency 3 tumors and high levels of HLA class I/class II and co-stimulatory molecules, were used to generate EB-VSTs [44][45][46].…”

“…First, they isolated EB-VSTs by using HLA-peptide multimers or streptamers [57] or by selecting T cells that secrete IFN-γ in response to EBV antigen stimulation (γ-capture) without any ex vivo expansion [53] (Figure 2). A small number of T cells responding in vitro to two HLA A2-restricted EBV-associated peptides (GLC and CLG) showed substantial in vivo expansion and dramatic clinical effects [53].…”

“…First, they isolated EB-VSTs by using HLA-peptide multimers or streptamers [57] or by selecting T cells that secrete IFN-γ in response to EBV antigen stimulation (γ-capture) without any ex vivo expansion [53] (Figure 2). A small number of T cells responding in vitro to two HLA A2-restricted EBV-associated peptides (GLC and CLG) showed substantial in vivo expansion and dramatic clinical effects [53]. Similarly, IFN-γ capture has been used clinically by Moosmann and colleagues [54], who isolated EB-VSTs by stimulating donor leukapheresis products overnight with EBV peptides, followed by IFN-γ capture and immunomagnetic separation (Figure 2).…”