Influenza vaccination in immunocompromised populations: Strategies to improve immunogenicity.

Immunocompromised individuals are at high risk of severe illness and complications from influenza infection. For this reason, immunization using inactivated influenza vaccines is recommended for transplant patients, individuals receiving immunosuppressant treatments, and other persons with immunodeficiency. However, these immunocompromised populations are more likely to have lower and non-protective responses to annual vaccination with a standard influenza vaccine. Here, we review strategies aimed to improve the immunogenicity of influenza vaccines in immunocompromised populations. The different strategies employed have included adjuvanted vaccines, high-dose vaccines, booster doses, intradermal vaccination, and temporary discontinuation of immunosuppressant treatment regimens. High-dose trivalent, inactivated, split-virus influenza vaccine (IIV3-HD) is so far one of the leading strategies for improving vaccine responses in HIV patients, transplant patients, and persons receiving immunosuppressant therapies for inflammatory diseases. Several studies in these populations have shown stronger humoral responses with IIV3-HD than existing standard-dose trivalent vaccine, and comparable safety. Accordingly, some scientific societies have stated that high-dose influenza vaccine could be a preferred option for immunocompromised patients. However, larger randomized controlled studies are needed to validate relative immunogenicity and safety of IIV3-HD and other enhanced vaccines and vaccination strategies in immunocompromised individuals.

Transcriptional profiling unveils type I and II interferon networks in blood and tissues across diseases.

Understanding how immune challenges elicit different responses is critical for diagnosing and deciphering immune regulation. Using a modular strategy to interpret the complex transcriptional host response in mouse models of infection and inflammation, we show a breadth of immune responses in the lung. Lung immune signatures are dominated by either IFN-γ and IFN-inducible, IL-17-induced neutrophil- or allergy-associated gene expression. Type I IFN and IFN-γ-inducible, but not IL-17- or allergy-associated signatures, are preserved in the blood. While IL-17-associated genes identified in lung are detected in blood, the allergy signature is only detectable in blood CD4+ effector cells. Type I IFN-inducible genes are abrogated in the absence of IFN-γ signaling and decrease in the absence of IFNAR signaling, both independently contributing to the regulation of granulocyte responses and pathology during Toxoplasma gondii infection. Our framework provides an ideal tool for comparative analyses of transcriptional signatures contributing to protection or pathogenesis in disease.

Immunogenic and Non-immunogenic Cell Death in the Tumor Microenvironment.

The host immune system is continuously exposed to dying cells and has evolved to distinguish between cell death events signaling potential threats and physiological apoptosis that should be tolerated. Tumors can use this distinction to their advantage, promoting apoptotic death of cancer cells to induce tolerance and evasion of immunosurveillance. On the other hand, stimuli that cause immunogenic death of cancer cells can induce an effective anti-tumor immune response. In this chapter we discuss different forms of cell death in the tumor microenvironment, and how these interact with host immune cells to impact tumor progression and cancer therapy. We focus on how cancer cells hijack aspects of cell death to promote tumor survival, and how anti-cancer treatments that activate immunogenic death modalities give strong and durable clinical efficacy.

Immunogenic stress and death of cancer cells: Contribution of antigenicity vs adjuvanticity to immunosurveillance.

Cancer cells are subjected to constant selection by the immune system, meaning that tumors that become clinically manifest have managed to subvert or hide from immunosurveillance. Immune control can be facilitated by induction of autophagy, as well as by polyploidization of cancer cells. While autophagy causes the release of ATP, a chemotactic signal for myeloid cells, polyploidization can trigger endoplasmic reticulum stress with consequent exposure of the "eat-me" signal calreticulin on the cell surface, thereby facilitating the transfer of tumor antigens into dendritic cells. Hence, both autophagy and polyploidization cause the emission of adjuvant signals that ultimately elicit immune control by CD8+ T lymphocytes. We investigated the possibility that autophagy and polyploidization might also affect the antigenicity of cancer cells by altering the immunopeptidome. Mass spectrometry led to the identification of peptides that were presented on major histocompatibility complex (MHC) class I molecules in an autophagy-dependent fashion or that were specifically exposed on the surface of polyploid cells, yet lost upon passage of such cells through immunocompetent (but not immunodeficient) mice. However, the preferential recognition of autophagy-competent and polyploid cells by the innate and cellular immune systems did not correlate with the preferential recognition of such peptides in vivo. Moreover, vaccination with such peptides was unable to elicit tumor growth-inhibitory responses in vivo. We conclude that autophagy and polyploidy increase the immunogenicity of cancer cells mostly by affecting their adjuvanticity rather than their antigenicity.

The renaissance of anti-neoplastic immunity from tumor cell demise.

Cancer therapies can temporarily reduce tumor burdens by inducing malignant cell death. However, cancer cure is still far from realization because tumors often gain resistance to current treatment and eventually relapse. Accumulating evidence suggests that successful cancer interventions require anti-tumor immunity. Therapy-induced cell stress responses ultimately result in one or more cell death modalities, including apoptosis, autophagy, necroptosis, and pyroptosis. These irreversible dying processes are accompanied by active or passive release of cell death-associated molecular patterns (CDAMPs), which can be sensed by corresponding pattern recognition receptors (PRR) on tumor-infiltrating immune cells. This crosstalk with the immune system can reawaken immune surveillance in the tumor microenvironment (TME). This review focuses on immune-modulatory properties of anti-cancer regimens and CDAMP-mediated communications between cell stress responses and the immune contexture of TME. In addition, we describe how immunogenic cell death can elicit strong and durable anti-tumor immune responses.

Efficacy and Tolerability of IncobotulinumtoxinA for Treating Glabellar Frown Lines in Korean Adults: A Postmarketing Observational Study.

BACKGROUND: IncobotulinumtoxinA is safe and effective in Caucasian adults. Its effects have been less documented in Asian adults. OBJECTIVE: To describe the efficacy and tolerability of incobotulinumtoxinA for treating glabellar frown lines (GFLs) in South Korean adults. METHODS: South Korean adults aged 18 to 65 years with moderate-to-severe GFLs received a single dose of 10 to 28 U incobotulinumtoxinA during routine clinical practice. After 30 ± 14 days, investigators assessed the efficacy using the Global Aesthetic Improvement Scale and rated tolerability using a 4-point scale. RESULTS: Six hundred seventy-three subjects were enrolled, of which 528 completed the study according to protocol. Glabellar frown lines improved in 98.7% (521/528) of subjects, with 30.8% of cases rated as "very much improved" and 47.4% as "much improved." The extent of improvement was unaffected by sex, age, and weight but was greater when the time between GFL identification and treatment was <6 months (p < .001) and when concomitant aesthetic nondrug treatments were used (p < .001). For 94% of subjects, tolerability was good or very good. All reported adverse events were transient and mild or moderate in severity. CONCLUSION: IncobotulinumtoxinA was well tolerated and effective for treating moderate-to-severe GFLs in Korean adults irrespective of age, sex, or weight.

Immune biomarkers for prognosis and prediction of responses to immune checkpoint blockade in cutaneous melanoma.

Existing clinical, anatomopathological and molecular biomarkers fail to reliably predict the prognosis of cutaneous melanoma. Biomarkers for determining which patients receive adjuvant therapies are needed. The emergence of new technologies and the discovery of new immune populations with different prognostic values allow the immune network in the tumor to be better understood. Importantly, new molecules identified and expressed by immune cells have been shown to reduce the antitumor immune efficacy of therapies, prompting researchers to develop antibodies targeting these so-called "immune checkpoints", which have now entered the oncotherapeutic armamentarium.

Immune Checkpoint Blockade, Immunogenic Chemotherapy or IFN-α Blockade Boost the Local and Abscopal Effects of Oncolytic Virotherapy.

Athough the clinical efficacy of oncolytic viruses has been demonstrated for local treatment, the ability to induce immune-mediated regression of distant metastases is still poorly documented. We report here that the engineered oncolytic vaccinia virus VVWR-TK-RR--Fcu1 can induce immunogenic cell death and generate a systemic immune response. Effects on tumor growth and survival was largely driven by CD8+ T cells, and immune cell infiltrate in the tumor could be reprogrammed toward a higher ratio of effector T cells to regulatory CD4+ T cells. The key role of type 1 IFN pathway in oncolytic virotherapy was also highlighted, as we observed a strong abscopal response in Ifnar-/- tumors. In this model, single administration of virus directly into the tumors on one flank led to regression in the contralateral flank. Moreover, these effects were further enhanced when oncolytic treatment was combined with immunogenic chemotherapy or with immune checkpoint blockade. Taken together, our results suggest how to safely improve the efficacy of local oncolytic virotherapy in patients whose tumors are characterized by dysregulated IFNα signaling. Cancer Res; 77(15); 4146-57. ©2017 AACR.

Enhancing the clinical coverage and anticancer efficacy of immune checkpoint blockade through manipulation of the gut microbiota.

Although anticancer therapy with immune checkpoint blockers has seen unprecedented success, it fails to control neoplasia in most patients and often causes immune-related adverse events (irAEs). Our recent research shows the immunostimulatory and antitumor effects of CTLA-4 blockade depend on distinct Bacteroides species of the gut microbiota, signifying novel approaches to improve such immunotherapies.

NKp30 isoforms and NKp30 ligands are predictive biomarkers of response to imatinib mesylate in metastatic GIST patients.

Despite effective targeted therapy acting on KIT and PDGFRA tyrosine kinases, gastrointestinal stromal tumors (GIST) escape treatment by acquiring mutations conveying resistance to imatinib mesylate (IM). Following the identification of NKp30-based immunosurveillance of GIST and the off-target effects of IM on NK cell functions, we investigated the predictive value of NKp30 isoforms and NKp30 soluble ligands in blood for the clinical response to IM. The relative expression and the proportions of NKp30 isoforms markedly impacted both event-free and overall survival, in two independent cohorts of metastatic GIST. Phenotypes based on disbalanced NKp30B/NKp30C ratio (ΔBClow) and low expression levels of NKp30A were identified in one third of patients with dismal prognosis across molecular subtypes. This ΔBClow blood phenotype was associated with a pro-inflammatory and immunosuppressive tumor microenvironment. In addition, detectable levels of the NKp30 ligand sB7-H6 predicted a worse prognosis in metastatic GIST. Soluble BAG6, an alternate ligand for NKp30 was associated with low NKp30 transcription and had additional predictive value in GIST patients with high NKp30 expression. Such GIST microenvironments could be rescued by therapy based on rIFN-α and anti-TRAIL mAb which reinstated innate immunity.

Mouse models in oncoimmunology.

Fundamental cancer research and the development of efficacious antineoplastic treatments both rely on experimental systems in which the relationship between malignant cells and immune cells can be studied. Mouse models of transplantable, carcinogen-induced or genetically engineered malignancies - each with their specific advantages and difficulties - have laid the foundations of oncoimmunology. These models have guided the immunosurveillance theory that postulates that evasion from immune control is an essential feature of cancer, the concept that the long-term effects of conventional cancer treatments mostly rely on the reinstatement of anticancer immune responses and the preclinical development of immunotherapies, including currently approved immune checkpoint blockers. Specific aspects of pharmacological development, as well as attempts to personalize cancer treatments using patient-derived xenografts, require the development of mouse models in which murine genes and cells are replaced with their human equivalents. Such 'humanized' mouse models are being progressively refined to characterize the leukocyte subpopulations that belong to the innate and acquired arms of the immune system as they infiltrate human cancers that are subjected to experimental therapies. We surmise that the ever-advancing refinement of murine preclinical models will accelerate the pace of therapeutic optimization in patients.

Fine-Tuning Cancer Immunotherapy: Optimizing the Gut Microbiome.

The equilibrium linking the intestinal microbiota, the intestinal epithelium, and the host immune system establishes host health and homeostasis, with perturbations of this balance resulting in chronic inflammatory and autoimmune immunopathologies. The mutualistic symbiosis between gut microbiota and host immunity raises the possibility that dysbiosis of the intestinal content also influences the outcome of cancer immunotherapy. Here, we present our recent findings that specific gut-resident bacteria determine the immunotherapeutic responses associated with CTLA-4 checkpoint blockade. This new evidence hints that interindividual differences in the microbiome may account for the significant heterogeneity in therapeutic and immunopathologic responses to immune checkpoint therapies. We discuss how this new understanding could improve the therapeutic coverage of immune checkpoint inhibitors, and potentially limit their immune-mediated toxicity, through the use of adjunctive "oncomicrobiotics" that indirectly promote beneficial immune responses through optimizing the gut microbiome. Cancer Res; 76(16); 4602-7. ©2016 AACR.

Resistance Mechanisms to Immune-Checkpoint Blockade in Cancer: Tumor-Intrinsic and -Extrinsic Factors.

Inhibition of immune regulatory checkpoints, such as CTLA-4 and the PD-1-PD-L1 axis, is at the forefront of immunotherapy for cancers of various histological types. However, such immunotherapies fail to control neoplasia in a significant proportion of patients. Here, we review how a range of cancer-cell-autonomous cues, tumor-microenvironmental factors, and host-related influences might account for the heterogeneous responses and failures often encountered during therapies using immune-checkpoint blockade. Furthermore, we describe the emerging evidence of how the strong interrelationship between the immune system and the host microbiota can determine responses to cancer therapies, and we introduce a concept by which prior or concomitant modulation of the gut microbiome could optimize therapeutic outcomes upon immune-checkpoint blockade.

Dendritic cell-derived exosomes as maintenance immunotherapy after first line chemotherapy in NSCLC.

Dendritic cell-derived exosomes (Dex) are small extracellular vesicles secreted by viable dendritic cells. In the two phase-I trials that we conducted using the first generation of Dex (IFN-γ-free) in end-stage cancer, we reported that Dex exerted natural killer (NK) cell effector functions in patients. A second generation of Dex (IFN-γ-Dex) was manufactured with the aim of boosting NK and T cell immune responses. We carried out a phase II clinical trial testing the clinical benefit of IFN-γ-Dex loaded with MHC class I- and class II-restricted cancer antigens as maintenance immunotherapy after induction chemotherapy in patients bearing inoperable non-small cell lung cancer (NSCLC) without tumor progression. The primary endpoint was to observe at least 50% of patients with progression-free survival (PFS) at 4 mo after chemotherapy cessation. Twenty-two patients received IFN-γ-Dex. One patient exhibited a grade three hepatotoxicity. The median time to progression was 2.2 mo and median overall survival (OS) was 15 mo. Seven patients (32%) experienced stabilization of >4 mo. The primary endpoint was not reached. An increase in NKp30-dependent NK cell functions were evidenced in a fraction of these NSCLC patients presenting with defective NKp30 expression. Importantly, MHC class II expression levels of the final IFN-γ-Dex product correlated with expression levels of the NKp30 ligand BAG6 on Dex, and with NKp30-dependent NK functions, the latter being associated with longer progression-free survival. This phase II trial confirmed the capacity of Dex to boost the NK cell arm of antitumor immunity in patients with advanced NSCLC.

Extracellular vesicles: masters of intercellular communication and potential clinical interventions.

Intercellular signaling via extracellular vesicles (EVs) is an underappreciated modality of cell-cell crosstalk that enables cells to convey packages of complex instructions to specific recipient cells. EVs transmit these instructions through their cargoes of multiple proteins, nucleic acids, and specialized lipids, which are derived from their cells of origin and allow for combinatorial effects upon recipient cells. This Review series brings together the recent progress in our understanding of EV signaling in physiological and pathophysiological conditions, highlighting how certain EVs, particularly exosomes, can promote or regulate infections, host immune responses, development, and various diseases - notably cancer. Given the diverse nature of EVs and their abilities to profoundly modulate host cells, this series puts particular emphasis on the clinical applications of EVs as therapeutics and as diagnostic biomarkers.

Dendritic cell-derived exosomes for cancer therapy.

DC-derived exosomes (Dex) are nanometer-sized membrane vesicles that are secreted by the sentinel antigen-presenting cells of the immune system: DCs. Like DCs, the molecular composition of Dex includes surface expression of functional MHC-peptide complexes, costimulatory molecules, and other components that interact with immune cells. Dex have the potential to facilitate immune cell-dependent tumor rejection and have distinct advantages over cell-based immunotherapies involving DCs. Accordingly, Dex-based phase I and II clinical trials have been conducted in advanced malignancies, showing the feasibility and safety of the approach, as well as the propensity of these nanovesicles to mediate T and NK cell-based immune responses in patients. This Review will evaluate the interactions of Dex with immune cells, their clinical progress, and the future of Dex immunotherapy for cancer.

Therapy-induced microenvironmental changes in cancer.

In the past decade, the focus of tumor biology research has been switching from the functional dissection of oncogenes and tumor suppressor genes to investigation of the cross-talk between tumor cells and their microenvironment. Tumorigenesis requires the organized assembly of cancer cells with non-malignant cells and non-cellular stroma, resembling an abnormal organogenesis. This process can be modulated by local cellular stress responses, such as senescence, ER stress and autophagy, and inflammatory and immunosuppressive cells and effector molecules within the tumor microenvironment (TME). Various cellular stress responses and cell death modalities are triggered in response to chemotherapies, radiotherapies, and targeted therapies (including immunotherapies). The exposure of immunostimulatory factors could (re)awaken anti-tumor immunity. Unexpectedly, the gut microbial flora is becoming recognized as an important external modulator of the TME. We will discuss in detail the TME changes that take place after certain cancer therapies, highlighting the importance of cellular stress responses, tumor-infiltrating immune cells, and microbiota-derived factors.

Analysis of Transcriptional Signatures in Response to Listeria monocytogenes Infection Reveals Temporal Changes That Result from Type I Interferon Signaling.

Analysis of the mouse transcriptional response to Listeria monocytogenes infection reveals that a large set of genes are perturbed in both blood and tissue and that these transcriptional responses are enriched for pathways of the immune response. Further we identified enrichment for both type I and type II interferon (IFN) signaling molecules in the blood and tissues upon infection. Since type I IFN signaling has been reported widely to impair bacterial clearance we examined gene expression from blood and tissues of wild type (WT) and type I IFNαß receptor-deficient (Ifnar1-/-) mice at the basal level and upon infection with L. monocytogenes. Measurement of the fold change response upon infection in the absence of type I IFN signaling demonstrated an upregulation of specific genes at day 1 post infection. A less marked reduction of the global gene expression signature in blood or tissues from infected Ifnar1-/- as compared to WT mice was observed at days 2 and 3 after infection, with marked reduction in key genes such as Oasg1 and Stat2. Moreover, on in depth analysis, changes in gene expression in uninfected mice of key IFN regulatory genes including Irf9, Irf7, Stat1 and others were identified, and although induced by an equivalent degree upon infection this resulted in significantly lower final gene expression levels upon infection of Ifnar1-/- mice. These data highlight how dysregulation of this network in the steady state and temporally upon infection may determine the outcome of this bacterial infection and how basal levels of type I IFN-inducible genes may perturb an optimal host immune response to control intracellular bacterial infections such as L. monocytogenes.

Chemokine receptor patterns in lymphocytes mirror metastatic spreading in melanoma.

Melanoma prognosis is dictated by tumor-infiltrating lymphocytes, the migratory and functional behavior of which is guided by chemokine or cytokine gradients. Here, we retrospectively analyzed the expression patterns of 9 homing receptors (CCR/CXCR) in naive and memory CD4+ and CD8+ T lymphocytes in 57 patients with metastatic melanoma (MMel) with various sites of metastases to evaluate whether T cell CCR/CXCR expression correlates with intratumoral accumulation, metastatic progression, and/or overall survival (OS). Homing receptor expression on lymphocytes strongly correlated with MMel dissemination. Loss of CCR6 or CXCR3, but not cutaneous lymphocyte antigen (CLA), on circulating T cell subsets was associated with skin or lymph node metastases, loss of CXCR4, CXCR5, and CCR9 corresponded with lung involvement, and a rise in CCR10 or CD103 was associated with widespread dissemination. High frequencies of CD8+CCR9+ naive T cells correlated with prolonged OS, while neutralizing the CCR9/CCL25 axis in mice stimulated tumor progression. The expansion of CLA-expressing effector memory CD8+ T cells in response to a single administration of CTLA4 blockade predicted disease control at 3 months in 47 patients with MMel. Thus, specific CCR/CXCR expression patterns on circulating T lymphocytes may guide potential diagnostic and therapeutic approaches.

Anticancer immunotherapy by CTLA-4 blockade relies on the gut microbiota.

Antibodies targeting CTLA-4 have been successfully used as cancer immunotherapy. We find that the antitumor effects of CTLA-4 blockade depend on distinct Bacteroides species. In mice and patients, T cell responses specific for B. thetaiotaomicron or B. fragilis were associated with the efficacy of CTLA-4 blockade. Tumors in antibiotic-treated or germ-free mice did not respond to CTLA blockade. This defect was overcome by gavage with B. fragilis, by immunization with B. fragilis polysaccharides, or by adoptive transfer of B. fragilis-specific T cells. Fecal microbial transplantation from humans to mice confirmed that treatment of melanoma patients with antibodies against CTLA-4 favored the outgrowth of B. fragilis with anticancer properties. This study reveals a key role for Bacteroidales in the immunostimulatory effects of CTLA-4 blockade.