Phenotype and Reactivity of Lymphocytes Expanded from Benign Prostate Hyperplasic Tissues and Prostate Cancer

Benign prostate hyperplasia (BPH) is a frequent condition in aging men, which affects life quality, causing principally lower urinary tract symptoms. Epidemiologic studies suggest that BPH may raise the risk of developing prostate cancer (PCa), most likely promoting a chronic inflammatory environment. Studies aiming at elucidating the link and risk factors that connect BPH and PCa are urgently needed to develop prevention strategies. The BPH microenvironment, similar to the PCa one, increases immune infiltration of the prostate, but, in contrast to PCa, immunosuppression may not be established yet. In this study, we found that prostate-infiltrating lymphocytes (PILs) expanded from hyperplastic prostate tissue recognized tumor-associated antigens (TAA) and autologous tissue, regardless of the presence of tumor cells. PILs expanded from BPH samples of patients with PCa, however, seem to respond more strongly to autologous tissue. Phenotypic characterization of the infiltrating PILs revealed a trend towards better expanding CD4⁺ T cells in infiltrates derived from PCa, but no significant differences were found. These findings suggest that T cell tolerance is compromised in BPH-affected prostates, likely due to qualitative or quantitative alterations of the antigenic landscape. Our data support the hypothesis that BPH increases the risk of PCa and may pave the way for new personalized preventive vaccine strategies for these patients.

C-type lectin receptor agonists elicit functional IL21-expressing Tfh cells and induce primary B cell responses in neonates

Introduction

C-type lectin receptor (CLR) agonists emerged as superior inducers of primary B cell responses in early life compared with Toll-like receptor (TLR) agonists, while both types of adjuvants are potent in adults.

Methods

Here, we explored the mechanisms accounting for the differences in neonatal adjuvanticity between a CLR-based (CAF®01) and a TLR4-based (GLA-SE) adjuvant administered with influenza hemagglutinin (HA) in neonatal mice, by using transcriptomics and systems biology analyses.

Results

On day 7 after immunization, HA/CAF01 increased IL6 and IL21 levels in the draining lymph nodes, while HA/GLA-SE increased IL10. CAF01 induced mixed Th1/Th17 neonatal responses while T cell responses induced by GLA-SE had a more pronounced Th2-profile. Only CAF01 induced T follicular helper (Tfh) cells expressing high levels of IL21 similar to levels induced in adult mice, which is essential for germinal center (GC) formation. Accordingly, only CAF01- induced neonatal Tfh cells activated adoptively transferred hen egg lysozyme (HEL)-specific B cells to form HEL+ GC B cells in neonatal mice upon vaccination with HEL-OVA.

Discussion

Collectively, the data show that CLR-based adjuvants are promising neonatal and infant adjuvants due to their ability to harness Tfh responses in early life.

Longitudinal analysis of DC subsets in patients with ovarian cancer: Implications for immunotherapy

Background

The use of circulating cDC1 to generate anti-cancer vaccines is among the most promising approaches to overcome the limited immunogenicity and clinical efficacy of monocyte-derived DC. However, the recurrent lymphopenia and the reduction of DC numbers and functionality in patients with cancer may represent an important limitation of such approach. In patients with ovarian cancer (OvC) that had received chemotherapy, we previously showed that cDC1 frequency and function were reduced.

Methods

We recruited healthy donors (HD, n=7) and patients with OvC at diagnosis and undergoing interval debulking surgery (IDS, n=6), primary debulking surgery (PDS, n=6) or at relapse (n=8). We characterized longitudinally phenotypic and functional properties of peripheral DC subsets by multiparametric flow cytometry.

Results

We show that the frequency of cDC1 and the total CD141+ DC capacity to take up antigen are not reduced at the diagnosis, while their TLR3 responsiveness is partially impaired in comparison with HD. Chemotherapy causes cDC1 depletion and increase in cDC2 frequency, but mainly in patients belonging to the PDS group, while in the IDS group both total lymphocytes and cDC1 are preserved. The capacity of total CD141+ DC and cDC2 to take up antigen is not impacted by chemotherapy, while the activation capacity upon Poly(I:C) (TLR3L) stimulation is further decreased.

Conclusions

Our study provides new information about the impact of chemotherapy on the immune system of patients with OvC and sheds a new light on the importance of considering timing with respect to chemotherapy when designing new vaccination strategies that aim at withdrawing or targeting specific DC subsets.

A TLR7/8 Agonist-Including DOEPC-Based Cationic Liposome Formulation Mediates Its Adjuvanticity Through the Sustained Recruitment of Highly Activated Monocytes in a Type I IFN-Independent but NF-κB-Dependent Manner

Novel adjuvants, such as Toll-like receptors (TLRs) agonists, are needed for the development of new formulations able to circumvent limitations of current vaccines. Among TLRs, TLR7/8 agonists represent promising candidates, as they are well described to enhance antigen-specific antibody responses and skew immunity toward T helper (T_H) 1 responses. We find here that the incorporation of the synthetic TLR7/8 ligand 3M-052 in a cationic DOEPC-based liposome formulation shifts immunity toward T_H1 responses and elicits strong and long-lasting germinal center and follicular T helper cell responses in adult mice. This reflects the prolonged recruitment of innate cells toward the site of immunization and homing of activated antigen-loaded monocytes and monocyte-derived dendritic cells toward draining lymph nodes. We further show that this adjuvanticity is independent of type I IFN but NF-κB-dependent. Overall, our data identify TLR7/8 agonists incorporated in liposomes as promising and effective adjuvants to enhance T_H1 and germinal center responses.

Quantitative and qualitative impairments in dendritic cell subsets of patients with ovarian or prostate cancer

BACKGROUND

Dendritic cells (DCs) are the most efficient antigen-presenting cells, hence initiating a potent and cancer-specific immune response. This ability (mainly using monocyte-derived DCs) has been exploited in vaccination strategies for decades with limited clinical efficacy. Another alternative would be the use of conventional DCs (cDCs) of which at least three subsets circulate in human blood: cDC1s (CD141^bright), cDC2s (CD1c⁺) and plasmacytoid DCs. Despite their paucity, technical advances may allow for their selection and clinical use. However, many assumptions concerning the DC subset biology depend on observations from mouse models, hindering their translational potential. In this study, we characterise human DCs in patients with ovarian cancer (OvC) or prostate cancer (PrC).

PATIENTS AND METHODS

Whole blood samples from patients with OvC or PrC and healthy donors (HDs) were evaluated by flow cytometry for the phenotypic and functional characterisation of DC subsets.

RESULTS

In both patient groups, the frequency of total CD141⁺ DCs was lower than that in HDs, but the cDC1 subset was only reduced in patients with OvC. CD141⁺ DCs showed a reduced response to the TLR3 agonist poly (I:C) in both groups of patients. An inverse correlation between the frequency of cDC1s and CA125, the OvC tumour burden marker, was observed. Consistently, high expression of CLEC9A in OvC tissue (The Cancer Genome Atlas data set) indicated a better overall survival.

CONCLUSIONS

cDC1s are reduced in patients with OvC, and CD141⁺ DCs are quantitatively and qualitatively impaired in patients with OvC or PrC. CD141⁺ DC activation may predict functional impairment. The loss of cDC1s may be a bad prognostic factor for patients with OvC.

Immunosuppressive Mediators Impair Proinflammatory Innate Lymphoid Cell Function in Human Malignant Melanoma

Innate lymphoid cells (ILC) are a family of immune cells that are emerging as potent orchestrators of immune responses. In cancer, ILCs display both pro- and antitumorigenic functions depending on the nature of the tumor and the involved ILC subset. Little is known about the ILC-tumor cross-talk in human melanoma. Here, we showed that ILC1s were enriched but functionally impaired in cytokine secretion in both peripheral blood mononuclear cells and tumor-infiltrated lymph nodes of melanoma patients. These findings were confirmed in vivo in murine cutaneous melanoma. Multiple immunosuppressive mechanisms are described in the melanoma microenvironment. Among others, adenosine and kynurenines were shown to suppress antitumor immune responses. By exposing ILCs to adenosine and kynurenines, we observed a similar shift toward the ILC1 subset distribution and impairment in proinflammatory cytokine production to that of patient samples studied ex vivo. Thus, we hypothesized that the immunosuppressive microenvironment of malignant melanoma might shape ILC subpopulations. Hence, we provide a rationale for the use of drugs targeting adenosine and kynurenine pathways in melanoma patients.

Adenosine mediates functional and metabolic suppression of peripheral and tumor-infiltrating CD8+ T cells

Background

Several mechanisms are present in the tumor microenvironment (TME) to impair cytotoxic T cell responses potentially able to control tumor growth. Among these, the accumulation of adenosine (Ado) contributes to tumor progression and represents a promising immunotherapeutic target. Ado has been shown to impair T cell effector function, but the role and mechanisms employed by Ado/Ado receptors (AdoRs) in modulating human peripheral and tumor-infiltrating lymphocyte (TIL) function are still puzzling.

Methods

CD8⁺ T cell cytokine production following stimulation was quantified by intracellular staining and flow cytometry. The cytotoxic capacity of tumor infiltrating lymphocytes (TILs) was quantified by the chromium release assay following co-culture with autologous or anti-CD3-loaded tumor cell lines. The CD8⁺ T cell metabolic fitness was evaluated by the seahorse assay and by the quantification of 2-NBDG uptake and CD71/CD98 upregulation upon stimulation. The expression of AdoRs was assessed by RNA flow cytometry, a recently developed technology that we validated by semiquantitative RT-PCR (qRT-PCR), while the impact on T cell function was evaluated by the use of selective antagonists and agonists. The influence of Ado/AdoR on the PKA and mTOR pathways was evaluated by phosphoflow staining of p-CREB and p-S6, respectively, and validated by western blot.

Results

Here, we demonstrate that Ado signaling through the A2A receptor (A2AR) in human peripheral CD8⁺ T cells and TILs is responsible for the higher sensitivity to Ado-mediated suppression of T central memory cells. We confirmed that Ado is able to impair peripheral and tumor-expanded T cell effector functions, and we show for the first time its impact on metabolic fitness. The Ado-mediated immunosuppressive effects are mediated by increased PKA activation that results in impairment of the mTORC1 pathway.

Conclusions

Our findings unveil A2AR/PKA/mTORC1 as the main Ado signaling pathway impairing the immune competence of peripheral T cells and TILs. Thus, p-CREB and p-S6 may represent useful pharmacodynamic and efficacy biomarkers of immunotherapies targeting Ado. The effect of Ado on T cell metabolic fitness reinforces the importance of the adenosinergic pathway as a target for next-generation immunotherapy.

Electronic supplementary material

The online version of this article (10.1186/s40425-019-0719-5) contains supplementary material, which is available to authorized users.

Neonatal T Follicular Helper Cells Are Lodged in a Pre-T Follicular Helper Stage Favoring Innate Over Adaptive Germinal Center Responses

T follicular helper (T_fh) cells have emerged as a critical limiting factor for controlling the magnitude of neonatal germinal center (GC) reactions and primary vaccine antibody responses. We compared the functional attributes of neonatal and adult T_fh cells at the transcriptomic level and demonstrated that the T_fh cell program is well-initiated in neonates although the T_fh gene-expression pattern (i.e., CXCR5, IL-21, BCL6, TBK1, STAT4, ASCL2, and c-MAF) is largely underrepresented as compared to adult T_fh cells. Importantly, we identified a TH2-bias of neonatal T_fh cells, with preferential differentiation toward short-lived pre-T_fh effector cells. Remarkably, adjuvantation with CpG-ODNs redirect neonatal pre-T_fh cells toward committed GC-T_fh cells, as illustrated by increased expression of T_fh signature genes and reduced expression of TH2-related genes.

Reactivating Immunity Primed by Acellular Pertussis Vaccines in the Absence of Circulating Antibodies: Enhanced Bacterial Control by TLR9 Rather Than TLR4 Agonist-Including Formulation

Pertussis is still observed in many countries despite of high vaccine coverage. Acellular pertussis (aP) vaccination is widely implemented in many countries as primary series in infants and as boosters in school-entry/adolescents/adults (including pregnant women in some). One novel strategy to improve the reactivation of aP-vaccine primed immunity could be to include genetically- detoxified pertussis toxin and novel adjuvants in aP vaccine boosters. Their preclinical evaluation is not straightforward, as it requires mimicking the human situation where T and B memory cells may persist longer than vaccine-induced circulating antibodies. Toward this objective, we developed a novel murine model including two consecutive adoptive transfers of the memory cells induced by priming and boosting, respectively. Using this model, we assessed the capacity of three novel aP vaccine candidates including genetically-detoxified pertussis toxin, pertactin, filamentous hemagglutinin, and fimbriae adsorbed to aluminum hydroxide, supplemented—or not—with Toll-Like-Receptor 4 or 9 agonists (TLR4A, TLR9A), to reactivate aP vaccine-induced immune memory and protection, reflected by bacterial clearance. In the conventional murine immunization model, TLR4A- and TLR9A-containing aP formulations induced similar aP-specific IgG antibody responses and protection against bacterial lung colonization as current aP vaccines, despite IL-5 down-modulation by both TLR4A and TLR9A and IL-17 up-modulation by TLR4A. In the absence of serum antibodies at time of boosting or exposure, TLR4A- and TLR9A-containing formulations both enhanced vaccine antibody recall compared to current aP formulations. Unexpectedly, however, protection was only increased by the TLR9A-containing vaccine, through both earlier bacterial control and accelerated clearance. This suggests that TLR9A-containing aP vaccines may better reactivate aP vaccine-primed pertussis memory and enhance protection than current or TLR4A-adjuvanted aP vaccines.

Personalized Dendritic Cell Vaccines-Recent Breakthroughs and Encouraging Clinical Results

With the advent of combined immunotherapies, personalized dendritic cell (DC)-based vaccination could integrate the current standard of care for the treatment of a large variety of tumors. Due to their proficiency at antigen presentation, DC are key coordinators of the innate and adaptive immune system, and have critical roles in the induction of antitumor immunity. However, despite proven immunogenicity and favorable safety profiles, DC-based immunotherapies have not succeeded at inducing significant objective clinical responses. Emerging data suggest that the combination of DC-based vaccination with other cancer therapies may fully unleash the potential of DC-based cancer vaccines and improve patient survival. In this review, we discuss the recent efforts to develop innovative personalized DC-based vaccines and their use in combined therapies, with a particular focus on ovarian cancer and the promising results of mutanome-based personalized immunotherapies.

Induction of Paracrine Signaling in Metastatic Melanoma Cells by PPARγ Agonist Rosiglitazone Activates Stromal Cells and Enhances Tumor Growth

In addition to improving insulin sensitivity in type 2 diabetes, the thiazolidinedione family of compounds and the pharmacologic activation of their best-characterized target PPARγ have been proposed as a therapeutic option for cancer treatment. In this study, we reveal a new mode of action for the thiazolidinedione rosiglitazone that can contribute to tumorigenesis. Rosiglitazone activated a tumorigenic paracrine communication program in a subset of human melanoma cells that involves the secretion of cytokines, chemokines, and angiogenic factors. This complex blend of paracrine signals activated nonmalignant fibroblasts, endothelial cells, and macrophages in a tumor-friendly way. In agreement with these data, rosiglitazone promoted human melanoma development in xenografts, and tumors exposed to rosiglitazone exhibited enhanced angiogenesis and inflammation. Together, these findings establish an important tumorigenic action of rosiglitazone in a subset of melanoma cells. Although studies conducted on cohorts of diabetic patients report overall benefits of thiazolidinediones in cancer prevention, our data suggest that exposure of established tumors to rosiglitazone may be deleterious.Significance: These findings uncover a novel mechanism by which the thiazolidinedione compound rosiglitazone contributes to tumorigenesis, thus highlighting a potential risk associated with its use in patients with established tumors. Cancer Res; 78(22); 6447-61. ©2018 AACR.

Overcoming the Neonatal Limitations of Inducing Germinal Centers through Liposome-Based Adjuvants Including C-Type Lectin Agonists Trehalose Dibehenate or Curdlan

Neonates and infants are more vulnerable to infections and show reduced responses to vaccination. Consequently, repeated immunizations are required to induce protection and early life vaccines against major pathogens such as influenza are yet unavailable. Formulating antigens with potent adjuvants, including immunostimulators and delivery systems, is a demonstrated approach to enhance vaccine efficacy. Yet, adjuvants effective in adults may not meet the specific requirements for activating the early life immune system. Here, we assessed the neonatal adjuvanticity of three novel adjuvants including TLR4 (glucopyranosyl lipid adjuvant-squalene emulsion), TLR9 (IC31^®), and Mincle (CAF01) agonists, which all induce germinal centers (GCs) and potent antibody responses to influenza hemagglutinin (HA) in adult mice. In neonates, a single dose of HA formulated into each adjuvant induced T follicular helper (T_FH) cells. However, only HA/CAF01 elicited significantly higher and sustained antibody responses, engaging neonatal B cells to differentiate into GCs already after a single dose. Although antibody titers remained lower than in adults, HA-specific responses induced by a single neonatal dose of HA/CAF01 were sufficient to confer protection against influenza viral challenge. Postulating that the neonatal adjuvanticity of CAF01 may result from the functionality of the C-type lectin receptor (CLR) Mincle in early life we asked whether other C-type lectin agonists would show a similar neonatal adjuvanticity. Replacing the Mincle agonist trehalose 6,6′-dibehenate by Curdlan, which binds to Dectin-1, enhanced antibody responses through the induction of similar levels of T_FH, GCs and bone marrow high-affinity plasma cells. Thus, specific requirements of early life B cells may already be met after a single vaccine dose using CLR-activating agonists, identified here as promising B cell immunostimulators for early life vaccines when included into cationic liposomes.