Wanyong Zeng

Bevacizumab plus Ipilimumab in Patients with Metastatic Melanoma

Hodi and colleagues report the safety and efficacy of targeting angiogenesis and CTLA-4 in a phase I trial of 46 patients with metastatic melanoma, which revealed the influence of VEGF-A blockade on inflammation, lymphocyte trafficking, and immune regulation, and their synergistic therapeutic effects. Ipilimumab improves survival in advanced melanoma and can induce immune-mediated tumor vasculopathy. Besides promoting angiogenesis, vascular endothelial growth factor (VEGF) suppresses dendritic cell maturation and modulates lymphocyte endothelial trafficking. This study investigated the combination of CTLA4 blockade with ipilimumab and VEGF inhibition with bevacizumab. Patients with metastatic melanoma were treated in four dosing cohorts of ipilimumab (3 or 10 mg/kg) with four doses at 3-week intervals and then every 12 weeks, and bevacizumab (7.5 or 15 mg/kg) every 3 weeks. Forty-six patients were treated. Inflammatory events included giant cell arteritis (n = 1), hepatitis (n = 2), and uveitis (n = 2). On-treatment tumor biopsies revealed activated vessel endothelium with extensive CD8+ and macrophage cell infiltration. Peripheral blood analyses demonstrated increases in CCR7+/−/CD45RO+ cells and anti-galectin antibodies. Best overall response included 8 partial responses, 22 instances of stable disease, and a disease-control rate of 67.4%. Median survival was 25.1 months. Bevacizumab influences changes in tumor vasculature and immune responses with ipilimumab administration. The combination of bevacizumab and ipilimumab can be safely administered and reveals VEGF-A blockade influences on inflammation, lymphocyte trafficking, and immune regulation. These findings provide a basis for further investigating the dual roles of angiogenic factors in blood vessel formation and immune regulation, as well as future combinations of antiangiogenesis agents and immune checkpoint blockade. Cancer Immunol Res; 2(7); 632–42. ©2014 AACR.

Autologous CLL cell vaccination early after transplant induces leukemia-specific T cells

BACKGROUND Patients with advanced hematologic malignancies remain at risk for relapse following reduced-intensity conditioning (RIC) allogeneic hematopoietic stem cell transplantation (allo-HSCT). We conducted a prospective clinical trial to test whether vaccination with whole leukemia cells early after transplantation facilitates the expansion of leukemia-reactive T cells and thereby enhances antitumor immunity. METHODS We enrolled 22 patients with advanced chronic lymphocytic leukemia (CLL), 18 of whom received up to 6 vaccines initiated between days 30 and 45 after transplantation. Each vaccine consisted of irradiated autologous tumor cells admixed with GM-CSF-secreting bystander cells. Serial patient PBMC samples following transplantation were collected, and the impact of vaccination on T cell activity was evaluated. RESULTS At a median follow-up of 2.9 (range, 1-4) years, the estimated 2-year progression-free and overall survival rates of vaccinated subjects were 82% (95% CI, 54%-94%) and 88% (95% CI, 59%-97%), respectively. Although vaccination only had a modest impact on recovering T cell numbers, CD8+ T cells from vaccinated patients consistently reacted against autologous tumor, but not alloantigen-bearing recipient cells with increased secretion of the effector cytokine IFN-γ, unlike T cells from nonvaccinated CLL patients undergoing allo-HSCT. Further analysis confirmed that 17% (range, 13%-33%) of CD8+ T cell clones isolated from 4 vaccinated patients by limiting dilution of bulk tumor-reactive T cells solely reacted against CLL-associated antigens. CONCLUSION Our studies suggest that autologous tumor cell vaccination is an effective strategy to advance long-term leukemia control following allo-HSCT. TRIAL REGISTRATION Clinicaltrials.gov NCT00442130. FUNDING NCI (5R21CA115043-2), NHLBI (5R01HL103532-03), and Leukemia and Lymphoma Society Translational Research Program.

Graft-versus-leukemia antigen CML66 elicits coordinated B-cell and T-cell immunity after donor lymphocyte infusion.

Purpose: The target antigens of graft-versus-leukemia that are tumor associated are incompletely characterized. Experimental Design: We examined responses developing against CML66, an immunogenic antigen preferentially expressed in myeloid progenitor cells identified from a patient with chronic myelogenous leukemia who attained long-lived remission following CD4+ donor lymphocyte infusion (DLI). Results: From this patient, CML66-reactive CD8+ T-cell clones were detected against an endogenously presented HLA-B*4403–restricted epitope (HDVDALLW). Neither CML66-specific antibody nor T-cell responses were detectable in peripheral blood before DLI. However, by 1 month after DLI, CD8+ T cells were present in peripheral blood and at 10-fold higher frequency in marrow. Subsequently, plasma antibody to CML66 developed in association with disease remission. Donor-derived CML66-reactive T cells were detected at low levels in vivo in marrow before DLI by ELISpot and by a nested PCR-based assay to detect clonotypic T-cell receptor sequences but not in blood of the patient pre-DLI nor of the graft donor. Conclusions: CD4+ DLI results in rapid expansion of preexisting marrow-resident leukemia-specific donor CD8+ T cells, followed by a cascade of antigen-specific immune responses detectable in blood. Our single-antigen analysis thus shows that durable posttransplant tumor immunity is directed in part against nonpolymorphic overexpressed leukemia antigens that elicit coordinated cellular and humoral immunity. Clin Cancer Res; 16(10); 2729–39. ©2010 AACR.

Adoptive Transfer of Invariant NKT Cells as Immunotherapy for Advanced Melanoma: A Phase I Clinical Trial

Purpose: Invariant NKT cells (iNKT) are innate-like CD1d-restricted T cells with immunoregulatory activity in diseases including cancer. iNKT from advanced cancer patients can have reversible defects including IFNγ production, and iNKT IFNγ production may stratify for survival. Previous clinical trials using iNKT cell activating ligand α-galactosylceramide have shown clinical responses. Therefore, a phase I clinical trial was performed of autologous in vitro expanded iNKT cells in stage IIIB–IV melanoma. Experimental Design: Residual iNKT cells [<0.05% of patient peripheral blood mononuclear cell (PBMC)] were purified from autologous leukapheresis product using an antibody against the iNKT cell receptor linked to magnetic microbeads. iNKT cells were then expanded with CD3 mAb and IL2 in vitro to obtain up to approximately 109 cells. Results: Expanded iNKT cells produced IFNγ, but limited or undetectable IL4 or IL10. Three iNKT infusions each were completed on 9 patients, and produced only grade 1–2 toxicities. The 4th patient onward received systemic GM-CSF with their second and third infusions. Increased numbers of iNKT cells were seen in PBMCs after some infusions, particularly when GM-CSF was also given. IFNγ responses to α-galactosylceramide were increased in PBMCs from some patients after infusions, and delayed-type hypersensitivity responses to Candida increased in 5 of 8 evaluated patients. Three patients have died, three were progression-free at 53, 60, and 65 months, three received further treatment and were alive at 61, 81, and 85 months. There was no clear correlation between outcome and immune parameters. Conclusions: Autologous in vitro expanded iNKT cells are a feasible and safe therapy, producing Th1-like responses with antitumor potential. Clin Cancer Res; 23(14); 3510–9. ©2017 AACR.

Cyclin D1^ Specific Cytotoxic T Lymphocytes Are Present in the Repertoire of Cancer Patients: Implications for Cancer Immunotherapy

Purpose: Cyclin D1, a key cell cycle regulator, is overexpressed in multiple types of cancer. Such tumor-associated genes may be useful targets for cancer immunotherapy. Nevertheless, it had previously been suggested that efficient T cells recognizing cyclin D1-derived epitopes are absent from the repertoire because of thymic deletion. We attempted to induce autologous CTL from healthy donors and patients with cyclin D1-overexpressing tumors using a highly efficient T-cell expansion system based on CD40-activated B cells as antigen-presenting cells. Experimental Design: Cyclin D1-derived, HLA-A*0201–restricted epitopes were predicted by multiple computer algorithms, screened in HLA-A2-binding assays, and used for T-cell stimulation. The generated CTL lines and clones were analyzed by IFN-γ enzyme-linked immunosorbent spot assay or cytolysis assay. Results: After screening, at least two naturally processed and presented HLA-A*0201–binding cyclin D1 epitopes were identified. CTL specific for these epitopes could be successfully generated from HLA-A2+ donors. T cells efficiently recognized target cells pulsed with the cognate peptide and cyclin D1-expressing tumor cell lines in an HLA-A*0201–restricted manner. More importantly, HLA-A*0201–matched, primary cyclin D1+ tumor cells were efficiently recognized by cyclin D1-specific CTL. These CTL could be generated from patients with mantle cell lymphoma and cyclin D1+ colon cancer. Conclusions: These results underscore that cyclin D1 needs to be considered as a target for broad-based antitumor immunotherapy.

Artificial antigen-presenting cells expressing CD80, CD70, and 4-1BB ligand efficiently expand functional T cells specific to tumor-associated antigens

Professional antigen-presenting cells (APCs), notably dendritic cells (DCs), are the most potent for expanding antigen-specific T cells ex vivo. However, the labor-intensive and expensive procedure for customized preparation of autologous APCs has hampered their broad clinical application. Artificial APC (aAPC) systems, which can be readily prepared from off-the-shelf components, have been proposed as a promising alternative to custom-made professional APCs. Here, in order to develop a novel aAPC system, we established K562 erythroleukemia cells expressing different combinations of co-stimulatory molecule ligands, CD80, CD70, and/or 4-1BB ligand (4-1BBL). When nucleofected with in vitro-generated mRNA encoding a tumor-associated antigen, MART-1, the K562 cells expressing all of CD80, CD70, and 4-1BBL were the most efficient for expansion of functional T cells specific to an HLA-A2-restricted immunodominant epitope, MART-126-35. In addition, only the K562 cells expressing all three of these co-stimulatory molecule ligands could clearly expand T cells specific to other less immunogenic antigen epitopes, gp100154-162 and Cyp1B1239-247, through transfection with in vitro generated gp100 and Cyp1B1 mRNA, respectively. These results indicated that non-redundant and synergistic effects of co-stimulation via CD28/CD80, CD27/CD70, and 4-1BB/4-1BBL might be critical for eliciting efficient expansion of T cells; co-stimulation via the 4-1BB/4-1BBL interaction might expand antigen-specific T cells by preventing apoptotic cell death triggered by specific antigens in the presence of the CD28/CD80 and CD27/CD70 signaling. Taken together, our findings suggested that this K562-based aAPC system expressing CD80, CD70, and 4-1BBL would be useful for efficiently stimulating functional antigen-specific T cells ex vivo, in particular when detailed information on the epitope specificities is unavailable.

Identification of human leucocyte antigen (HLA)-A*0201-restricted cytotoxic T lymphocyte epitopes derived from HLA-DOβ as a novel target for multiple myeloma

Despite the recent development of effective therapeutic agents against multiple myeloma (MM), new therapeutic approaches, including immunotherapies, remain to be developed. Here we identified novel human leucocyte antigen (HLA)‐A*0201 (HLA‐A2)‐restricted cytotoxic T lymphocyte (CTL) epitopes from a B cell specific molecule HLA‐DOβ (DOB) as a potential target for MM. By DNA microarray analysis, the HLA‐DOB expression in MM cells was significantly higher than that in normal plasma cells. Twenty‐five peptides were predicted to bind to HLA‐A2 from the amino acid sequence of HLA‐DOB. When screened for the immunogenicity in HLA‐A2‐transgenic mice immunized with HLA‐DOB cDNA, 4 peptides were substantially immunogenic. By mass spectrometry analysis of peptides eluted from HLA‐A2‐immunoprecipitates of MM cell lines, only two epitopes, HLA‐DOB232–240 (FLLGLIFLL) and HLA‐DOB185–193 (VMLEMTPEL), were confirmed for their physical presence on cell surface. When healthy donor blood was repeatedly stimulated in vitro with these two peptides and assessed by antigen‐specific γ‐interferon secretion, HLA‐DOB232–240 was more immunogenic than HLA‐DOB185–193. Additionally, the HLA‐DOB232–240‐specific CTLs, but not the HLA‐DOB185–193‐specific CTLs, displayed an major histocompatibility complex class I‐restricted reactivity against MM cell lines expressing both HLA‐A2 and HLA‐DOB. Taken together, based on the physical presence on tumour cell surface and high immunogenicity, HLA‐DOB232–240 might be useful for developing a novel immunotherapy against MM.

Impaired Tumor Antigen Processing by Immunoproteasome-expressing CD40-Activated B cells and Dendritic Cells

Professional APCs, such as dendritic cells, are routinely used in vitro for the generation of cytotoxic T lymphocytes specific for tumor antigens. In addition to dendritic cells, CD40-activated B cells and variant K562 leukemic cells can be readily transfected with nucleic acids for in vitro and in vivo antigen presentation. However, the expression of immunoproteasome components in dendritic cells may preclude display of tumor antigens such as Mart1/MelanA. Here, we use three target epitopes, two derived from tumor antigens [Mart126–34 (M26) and Cyp1B1239–247 (Cyp239)] and one derived from the influenza A viral antigen [FluM158–66 (FluM58)], to demonstrate that CD40-activated B cells, like dendritic cells, have a limited capability to process certain tumor antigens. In contrast, the K562 HLA-A*0201 transfectant efficiently processes and presents M26 and Cyp239 as well as the influenza FluM58 epitopes to T cells. These results demonstrate that the choice of target APC for gene transfer of tumor antigens may be limited by the relative efficacy of proteasome components to process certain tumor epitopes. Importantly, K562 can be exploited as an artificial APC, efficient in processing both M26 and Cyp239 epitopes and presumably, by extension, other relevant tumor antigens.

A clonal model for human CD8+ regulatory T cells: unrestricted contact-dependent killing of activated CD4+ T cells.

Previous studies in murine systems have demonstrated that CD8+ Treg cells down‐regulate immune responses in vivo through suppressing activated CD4+ T cells. Here we describe novel regulatory CD8+ T‐cell clones isolated from healthy human peripheral blood following in vitro stimulation with autologous Epstein–Barr virus (EBV)‐specific CD4+ T cells. TCR activation of CD4+ target T cells was required for CD8+ Treg cells to exert suppressive activity, which was mediated through lysis of CD4+ targets in a cell contact‐dependent manner. Suppression was independent of Foxp3 expression in CD8+ Treg cells, HLA compatibility between CD8+ Treg cells and CD4+ target cells and antigen‐specificity of CD4+ target T cells. CD8+ Treg clones expressed CD3 and a variety of TCR Vβ chains as well as CD56, CD69, CD62L and CD95 but did not express CD16, CD161, CXCR4 and CCR7. When used together, antibodies specific for CD11a/CD18 and CD8 inhibited suppressive activity of CD8+ Treg clones. The ability to establish clonal CD8+ T cells that maintain regulatory function in vitro will facilitate further studies to define this population in vivo and to identify the mechanisms used for recognition and suppression of activated target cells.