Active and Adoptive Immunotherapy in Indolent Lymphoproliferative Diseases

Although monoclonal antibody (mAb) therapy has improved the outcome of low-grade B-cell non-Hodgkin lymphomas (B-NHL), they remain incurable diseases. The intimate relationship between immune cells and lymphomas for its maintenance and progression suggests that immunotherapy may represent a valuable strategy towards the control and eradication of these malignancies. Despite initial successes of anti-idiotype vaccination, its clinical benefits have not been definitely proven. New insights into the mechanisms whereby (i) tumour escape immunity, (ii) certain anticancer treatments exert immunogenic functions, (iii) microenvironment influences lymphoma growth should open new ways for immunotherapeutic intervention. Towards this goal, dendritic cells (DCs) loaded with autologous killed tumour cells were used to immunize indolent B-NHL patients against a wide spectrum of tumour antigens, thereby enhancing the possibility of a clinical success. A significant correlation was observed between clinical responses and both regulatory T cell frequency decrease and natural killer cell activation. These effects were positively associated with calreticulin and heat shock protein (HSP)90 surface expression in dying tumour cells used in the vaccine formulations. Therapeutic improvements might thus be accomplished by stimulating tumour release of "eat-me” signals. T-cell maturation and anti-lymphoma activation were also associated with a positive clinical outcome. A novel artificial expansion system was developed to boost these effects through the ex-vivo generation of functional, long-lasting polyclonal T cells and adoptive cell therapy. Finally, the investigation of tumour-restricted humoral immunity in clinical responders permitted the serological identification of HSP105 as a novel potential NHL immunodominant antigen. HSP105 expression correlated with B-NHL proliferation and aggressiveness. A specific neutralizing Ab significantly reduced lymphoma burden in xenotransplanted mice, thus laying the basis for a novel passive immunotherapy for B-NHL. Collectively, these results provide important information on mechanisms underlying anti-lymphoma immunity and open up the possibility of improving active and passive immunotherapy to the treatment of indolent B-NHLs

Artificial Antigen Presenting Cells With Preclustered anti-CD28/-CD3/-LFA-1 Monoclonal Antibodies Are Highly Effective To Induce The Ex-Vivo Expansion Of Functional Human Antitumor T Cells

Effective adoptive T cell therapy requires the _ex vivo_ generation of functional T lymphocytes with a long lifespan _in vivo_. We evaluated _in vitro_ T cell expansion by artificial antigen presenting cells (aAPC) generated with activating (human anti-CD3), co-stimulating (human anti-CD28) and adhesion (human anti-LFA-1) monoclonal antibodies pre-clustered in microdomains (MDs) held by a liposome scaffold. The co-localization of T cell ligands in MDs and the targeting of an adhesion protein, increasing the efficiency of immunological synapse formations, represent the novelties of our system. These aAPCs allowed increased expansion of polyclonal CD4^+^ and CD8^+^ T cells and of tumor antigen-specific CD8^+^ T cells compared to anti-CD28- and anti-CD3-coated microbeads and to immobilized anti-CD3. These aAPCs allowed the generation of T cells displaying an immunophenotype consistent with long-term _in vivo_ persistence, without increasing the frequency of regulatory T cells. Finally, our aAPCs proved to be suitable for large scale T cell expansion required in immunotherapy trials

Primary Effusion Lymphoma Cell Death Induced by Bortezomib and AG 490 Activates Dendritic Cells through CD91

To understand how cytotoxic agent-induced cancer cell death affects the immune system is of fundamental importance to stimulate immune response to counteract the high mortality due to cancer. Here we compared the immunogenicity of Primary Effusion Lymphoma (PEL) cell death induced by anticancer drug Bortezomib (Velcade) and Tyrphostin AG 490, a Janus Activated Kinase 2/signal trasducer and activator of transcription-3 (JAK2/STAT3) inhibitor. We show that both treatments were able to induce PEL apoptosis with similar kinetics and promote dendritic cells (DC) maturation. The surface expression of molecules involved in immune activation, namely calreticulin (CRT), heat shock proteins (HSP) 90 and 70 increased in dying cells. This was correlated with DC activation. We found that PEL cell death induced by Bortezomib was more effective in inducing uptake by DC compared to AG 490 or combination of both drugs. However the DC activation induced by all treatments was completely inhibited when these cells were pretreated with a neutralizing antiboby directed against the HSP90/70 and CRT common receptor, CD91. The activation of DC by Bortezomib and AG 490 treated PEL cells, as seen in the present study, might have important implications for a combined chemo and immunotherapy in such patients

Updates on radiotherapy-immunotherapy combinations: Proceedings of 6(th) annual ImmunoRad conference

Focal radiation therapy (RT) has attracted considerable attention as a combinatorial partner for immunotherapy (IT), largely reflecting a well-defined, predictable safety profile and at least some potential for immunostimulation. However, only a few RT-IT combinations have been tested successfully in patients with cancer, highlighting the urgent need for an improved understanding of the interaction between RT and IT in both preclinical and clinical scenarios. Every year since 2016, ImmunoRad gathers experts working at the interface between RT and IT to provide a forum for education and discussion, with the ultimate goal of fostering progress in the field at both preclinical and clinical levels. Here, we summarize the key concepts and findings presented at the Sixth Annual ImmunoRad conference

Toward a comprehensive view of cancer immune responsiveness: a synopsis from the SITC workshop.

Tumor immunology has changed the landscape of cancer treatment. Yet, not all patients benefit as cancer immune responsiveness (CIR) remains a limitation in a considerable proportion of cases. The multifactorial determinants of CIR include the genetic makeup of the patient, the genomic instability central to cancer development, the evolutionary emergence of cancer phenotypes under the influence of immune editing, and external modifiers such as demographics, environment, treatment potency, co-morbidities and cancer-independent alterations including immune homeostasis and polymorphisms in the major and minor histocompatibility molecules, cytokines, and chemokines. Based on the premise that cancer is fundamentally a disorder of the genes arising within a cell biologic process, whose deviations from normality determine the rules of engagement with the host\u27s response, the Society for Immunotherapy of Cancer (SITC) convened a task force of experts from various disciplines including, immunology, oncology, biophysics, structural biology, molecular and cellular biology, genetics, and bioinformatics to address the complexity of CIR from a holistic view. The task force was launched by a workshop held in San Francisco on May 14-15, 2018 aimed at two preeminent goals: 1) to identify the fundamental questions related to CIR and 2) to create an interactive community of experts that could guide scientific and research priorities by forming a logical progression supported by multiple perspectives to uncover mechanisms of CIR. This workshop was a first step toward a second meeting where the focus would be to address the actionability of some of the questions identified by working groups. In this event, five working groups aimed at defining a path to test hypotheses according to their relevance to human cancer and identifying experimental models closest to human biology, which include: 1) Germline-Genetic, 2) Somatic-Genetic and 3) Genomic-Transcriptional contributions to CIR, 4) Determinant(s) of Immunogenic Cell Death that modulate CIR, and 5) Experimental Models that best represent CIR and its conversion to an immune responsive state. This manuscript summarizes the contributions from each group and should be considered as a first milestone in the path toward a more contemporary understanding of CIR. We appreciate that this effort is far from comprehensive and that other relevant aspects related to CIR such as the microbiome, the individual\u27s recombined T cell and B cell receptors, and the metabolic status of cancer and immune cells were not fully included. These and other important factors will be included in future activities of the taskforce. The taskforce will focus on prioritization and specific actionable approach to answer the identified questions and implementing the collaborations in the follow-up workshop, which will be held in Houston on September 4-5, 2019

Correction to: Toward a comprehensive view of cancer immune responsiveness: a synopsis from the SITC workshop.

Following publication of the original article [1], the author reported that an author name, Roberta Zappasodi, was missed in the authorship list

Identification of unique neoantigen qualities in long-term survivors of pancreatic cancer

Pancreatic ductal adenocarcinoma is a lethal cancer with fewer than 7% of patients surviving past 5 years. T-cell immunity has been linked to the exceptional outcome of the few long-term survivors1,2, yet the relevant antigens remain unknown. Here we use genetic, immunohistochemical and transcriptional immunoprofiling, computational biophysics, and functional assays to identify T-cell antigens in long-term survivors of pancreatic cancer. Using whole-exome sequencing and in silico neoantigen prediction, we found that tumours with both the highest neoantigen number and the most abundant CD8+ T-cell infiltrates, but neither alone, stratified patients with the longest survival. Investigating the specific neoantigen qualities promoting T-cell activation in long-term survivors, we discovered that these individuals were enriched in neoantigen qualities defined by a fitness model, and neoantigens in the tumour antigen MUC16 (also known as CA125). A neoantigen quality fitness model conferring greater immunogenicity to neoantigens with differential presentation and homology to infectious disease-derived peptides identified long-term survivors in two independent datasets, whereas a neoantigen quantity model ascribing greater immunogenicity to increasing neoantigen number alone did not. We detected intratumoural and lasting circulating T-cell reactivity to both high-quality and MUC16 neoantigens in long-term survivors of pancreatic cancer, including clones with specificity to both high-quality neoantigens and predicted cross-reactive microbial epitopes, consistent with neoantigen molecular mimicry. Notably, we observed selective loss of high-quality and MUC16 neoantigenic clones on metastatic progression, suggesting neoantigen immunoediting. Our results identify neoantigens with unique qualities as T-cell targets in pancreatic ductal adenocarcinoma. More broadly, we identify neoantigen quality as a biomarker for immunogenic tumours that may guide the application of immunotherapies