Abstract 2954: MAIT engagers: An efficacious novel modality in the field of T-cell engagers for the treatment of solid tumors

Background: Mucosal-Associated Invariant T cells (MAITs) are an abundant subset of non-conventional T-cells with potent cytotoxic capacity (up to 20% of circulating T-cells) that are naturally resident in many tissues and solid tumors. T-cell redirection is a clinically validated approach to treating haematological cancers but has limited success in solid tumors. Classical T-cell engagers (TCE) bind the epsilon chain of the TCR leading to activation of all T-cells. MAIT cells utilize a semi-invariant TCR and recognize bacterial metabolites presented in the context of the MR1 protein. Biomunex has generated bispecific antibodies that bind the MAIT semi-invariant TCR (iTCR) and the HER2 receptor tyrosine kinase expressed on tumor cells. This enables the formation of an efficient immunological synapse and exclusive redirection of MAIT cells to directly kill cancer cells.

Methods: Using the Biomunex proprietary BiXAb® platform, bispecific, tetravalent antibodies were generated that target the MAIT iTCR and HER2. Specific binding to the two targets was demonstrated by ELISA, DUAL ELISA and in FACS. In general, BiXAb®-mediated MAIT-cell activation, proliferation and degranulation were followed by gating on MAIT cells within a purified CD8 cell population. Tumor cell lines expressing varying amounts of HER2 were co-cultured with MAIT cells (peripheral and tumor-resident) and the BiXAb®s in several cytotoxic assays which were evaluated by measuring Chromium release, LDH release and FACS.

Results: The iTCR x HER2 BiXAb® efficiently binds both target proteins with similar affinities to the parental Mabs and can bind both simultaneously, as judged by Dual ELISA. The iTCR x HER2 BiXAb® binds the MAIT-cell TCR and can bind cancer cells over a wide range of HER2 expression. BiXAb® engagement of MAIT cells and cancer cells leads to rapid activation, proliferation and degranulation of MAIT cells. In a population of PBMCs, only MAIT cells are activated by the BiXAb®. Even at low effector to target ratios (E:T = 2:1), MAIT cells efficiently kill engaged cancer cells in a HER2-dependent manner (over 50% cytotoxicity in 18 hrs). The MAIT-directed BiXAb® does not activate other T-cell subsets and hence has significantly reduced cytokine release when compared to a classical T-cell engager.

Conclusions: BiXAb® mediated MAIT cell redirection leads to efficient killing of cancer cells and is a promising new approach for the treatment of solid tumors. The iTCR x HER2 BiXAb® has no impact on the general CD8 or CD4 T-cell population which may address some of the clinical limitations of classical TCEs.

Citation Format: Simon Edward Plyte, Marie Fraudeau, Jonathan Grivel, Paloma Hougron, Katja Klausz, Dorothee Winterberg, Britta von Below, Alexandre Ivagnes, Claire Germain, Sebastian Amigorena, Eugene Zhukovsky, Matthias Peipp, Pierre-Emmanuel Gerard, Olivier Lantz, Julie Prigent. MAIT engagers: An efficacious novel modality in the field of T-cell engagers for the treatment of solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2954.

Regulatory T cells infiltrate the tumor-induced tertiary lymphoïd structures and are associated with poor clinical outcome in NSCLC

On one hand, regulatory T cells (Tregs) play an immunosuppressive activity in most solid tumors but not all. On the other hand, the organization of tumor-infiltrating immune cells into tertiary lymphoid structures (TLS) is associated with long-term survival in most cancers. Here, we investigated the role of Tregs in the context of Non-Small Cell Lung Cancer (NSCLC)-associated TLS. We observed that Tregs show a similar immune profile in TLS and non-TLS areas. Autologous tumor-infiltrating Tregs inhibit the proliferation and cytokine secretion of CD4⁺ conventional T cells, a capacity which is recovered by antibodies against Cytotoxic T-Lymphocyte-Associated protein-4 (CTLA-4) and Glucocorticoid-Induced TNFR-Related protein (GITR) but not against other immune checkpoint (ICP) molecules. Tregs in the whole tumor, including in TLS, are associated with a poor outcome of NSCLC patients, and combination with TLS-dendritic cells (DCs) and CD8⁺ T cells allows higher overall survival discrimination. Thus, Targeting Tregs especially in TLS may represent a major challenge in order to boost anti-tumor immune responses initiated in TLS.

LLT1-CD161 Interaction in Cancer: Promises and Challenges

The success of immune checkpoint therapy in cancer has changed our way of thinking, promoting the design of future cancer treatments that places the immune system at the center stage. The knowledge gained on immune regulation and tolerance helped the identification of promising new clinical immune targets. Among them, the lectin-like transcript 1 (LLT1) is the ligand of CD161 (NKR-P1A) receptor expressed on natural killer cells and T cells. LLT1/CD161 interaction modulates immune responses but the exact nature of the signals delivered is still partially resolved. Investigation on the role of LLT1/CD161 interaction has been hampered by the lack of functional homologues in animal models. Also, some studies have been misled by the use of non-specific reagents. Recent studies and meta-analyses of single cell data are bringing new insights into the function of LLT1 and CD161 in human pathology and notably in cancer. The advances made on the characterization of the tumor microenvironment prompt us to integrate LLT1/CD161 interaction into the equation. This review recapitulates the key findings on the expression profile of LLT1 and CD161, their regulation, the role of their interaction in cancer development, and the relevance of targeting LLT1/CD161 interaction.

Abstract CT021: INVAC-1, an optimized telomerase DNA vaccine in patients with advanced solid tumors: Final results of first-in-human phase I study

Background INVAC-1 is an optimized DNA plasmid encoding an inactive form of human Telomerase Reverse Transcriptase (hTERT), a universal tumor antigen expressed in most of human tumors with little or no expression in normal somatic cells. Primary pharmacodynamics, safety and toxicology studies showed that INVAC-1 was enzymatically inactive, immunogenically safe and well tolerated. In murine models, we demonstrated that INVAC-1 was able to induce hTERT specific cellular immune responses with CD4+ Th1 effector and memory CD8+ T-cells as well as slow tumor growth and increase survival rate by 50% in tumor-bearing mice. Methods We conducted a First-In-Human (FIH) study, 2-centre, Phase I, open label, 3+3 escalation design and multiple dose study examining the safety and tolerability of INVAC-1 administered at three dose levels (100, 400 and 800 µg) in 26 patients with relapsed or solid refractory tumors. INVAC-1 was administered either by intradermal (ID) injection followed by electroporation (EP) (n=20) or by Tropis® Needle Free Injection System (n=6). Results INVAC-1 vaccination was safe and well tolerated when administered ID (either with EP or by Tropis®) at the three tested doses. Only one treatment-related grade 3 SAE was reported. 58% of patients experienced disease stabilization up to 9.9 months. One-year survival was reached for 65% of patients. INVAC-1 elicited both hTERT specific Th1-dominant CD4 and cytotoxic CD8 T cell responses with no vaccine-induced peripheral immunosuppression. Anti-hTERT immune responses were enhanced by adding anti-PD-1 immune checkpoint inhibitor ex vivo. In addition, INVAC-1 vaccination was able to promote epitope spreading. Finally, correlation analysis between clinical and immunological data showed that patients with OS >1 year presented a significantly higher hTERT immune response after INVAC-1 vaccination compared to patients with OS <1 year. Moreover, estimated median OS in INVAC-1 immune responders was 17.4 months vs. 7 months for non-responders. Conclusion INVAC-1 vaccination was safe, well tolerated and immunogenic when administered ID at the three tested doses. Disease stabilization was observed for the majority of patients during the treatment period and beyond. Clinical trial identification #NCT02301754

Citation Format: Julie Garibal, Jacques Medioni, Luis Teixeira, Olivier Adotevi, Marie-Agnès Dragon-Durey, Caroline Laheurte, Claire Germain, Marie Escande, Maria Wehbe, Valérie Doppler, Thierry Huet, Pierre Langlade Demoyen. INVAC-1, an optimized telomerase DNA vaccine in patients with advanced solid tumors: Final results of first-in-human phase I study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT021.

Tertiary Lymphoid Structure-B Cells Narrow Regulatory T Cells Impact in Lung Cancer Patients

The presence of tertiary lymphoid structures (TLS) in the tumor microenvironment is associated with better clinical outcome in many cancers. In non-small cell lung cancer (NSCLC), we have previously showed that a high density of B cells within TLS (TLS-B cells) is positively correlated with tumor antigen-specific antibody responses and increased intratumor CD4⁺ T cell clonality. Here, we investigated the relationship between the presence of TLS-B cells and CD4⁺ T cell profile in NSCLC patients. The expression of immune-related genes and proteins on B cells and CD4⁺ T cells was analyzed according to their relationship to TLS-B density in a prospective cohort of 56 NSCLC patients. We observed that tumor-infiltrating T cells showed marked differences according to TLS-B cell presence, with higher percentages of naïve, central-memory, and activated CD4⁺ T cells and lower percentages of both immune checkpoint (ICP)-expressing CD4⁺ T cells and regulatory T cells (Tregs) in the TLS-B^high tumors. A retrospective study of 538 untreated NSCLC patients showed that high TLS-B cell density was even able to counterbalance the deleterious impact of high Treg density on patient survival, and that TLS-B^high Treg^low patients had the best clinical outcomes. Overall, the correlation between the density of TLS-B^high tumors with early differentiated, activated and non-regulatory CD4⁺ T cell cells suggest that B cells may play a central role in determining protective T cell responses in NSCLC patients.

Natural killer cells in the human lung tumor microenvironment display immune inhibitory functions

BACKGROUND

Natural killer (NK) cells play a crucial role in tumor immunosurveillance through their cytotoxic effector functions and their capacity to interact with other immune cells to build a coordinated antitumor immune response. Emerging data reveal NK cell dysfunction within the tumor microenvironment (TME) through checkpoint inhibitory molecules associated with a regulatory phenotype.

OBJECTIVE

We aimed at analyzing the gene expression profile of intratumoral NK cells compared with non-tumorous NK cells, and to characterize their inhibitory function in the TME.

METHODS

NK cells were sorted from human lung tumor tissue and compared with non- tumoral distant lungs.

RESULTS

In the current study, we identify a unique gene signature of NK cell dysfunction in human non-small cell lung carcinoma (NSCLC). First, transcriptomic analysis reveals significant changes related to migratory pattern with a downregulation of sphingosine-1-phosphate receptor 1 (S1PR1) and CX3C chemokine receptor 1 (CX3CR1) and overexpression of C-X-C chemokine receptor type 5 (CXCR5) and C-X-C chemokine receptor type 6 (CXCR6). Second, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and killer cell lectin like receptor (KLRC1) inhibitory molecules were increased in intratumoral NK cells, and CTLA-4 blockade could partially restore MHC class II level on dendritic cell (DC) that was impaired during the DCs/NK cell cross talk. Finally, NK cell density impacts the positive prognostic value of CD8⁺ T cells in NSCLC.

CONCLUSIONS

These findings demonstrate novel molecular cues associated with NK cell inhibitory functions in NSCLC.

Impaired Tumor-Infiltrating T Cells in Patients with Chronic Obstructive Pulmonary Disease Impact Lung Cancer Response to PD-1 Blockade

RATIONALE

Patients with chronic obstructive pulmonary disease (COPD) have a higher prevalence of lung cancer. The chronic inflammation associated with COPD probably promotes the earliest stages of carcinogenesis. However, once tumors have progressed to malignancy, the impact of COPD on the tumor immune microenvironment remains poorly defined, and its effects on immune-checkpoint blockers' efficacy are still unknown.

OBJECTIVES

To study the impact of COPD on the immune contexture of non-small cell lung cancer.

METHODS

We performed in-depth immune profiling of lung tumors by immunohistochemistry and we determined its impact on patient survival (n = 435). Tumor-infiltrating T lymphocyte (TIL) exhaustion by flow cytometry (n = 50) was also investigated. The effectiveness of an anti-PD-1 (programmed cell death-1) treatment (nivolumab) was evaluated in 39 patients with advanced-stage non-small cell lung cancer. All data were analyzed according to patient COPD status.

MEASUREMENTS AND MAIN RESULTS

Remarkably, COPD severity is positively correlated with the coexpression of PD-1/TIM-3 (T-cell immunoglobulin and mucin domain-containing molecule-3) by CD8 T cells. In agreement, we observed a loss of CD8 T cell-associated favorable clinical outcome in COPD⁺ patients. Interestingly, a negative prognostic value of PD-L1 (programmed cell death ligand 1) expression by tumor cells was observed only in highly CD8 T cell-infiltrated tumors of COPD⁺ patients. Finally, data obtained on 39 patients with advanced-stage non-small cell lung cancer treated by an anti-PD-1 antibody showed longer progression-free survival in COPD⁺ patients, and also that the association between the severity of smoking and the response to nivolumab was preferentially observed in COPD⁺ patients.

CONCLUSIONS

COPD is associated with an increased sensitivity of CD8 tumor-infiltrating T lymphocytes to immune escape mechanisms developed by tumors, thus suggesting a higher sensitivity to PD-1 blockade in patients with COPD.

Identification of Tertiary Lymphoid Structure-Associated Follicular Helper T Cells in Human Tumors and Tissues

Follicular helper T (Tfh) cells are major components of the humoral immune response due to their pivotal role in germinal center formation and antibody affinity maturation following B-cell isotype switching. This CD4⁺ T-cell subtype is mainly found in the B-cell zone of secondary lymphoid organs as well as in tertiary lymphoid structures (TLS), which are highly organized structures composed of T and B cells, occasionally found at the invasive margin in the tumor microenvironment.We describe here how to perform immunofluorescence staining of tumor tissue sections and multicolor flow cytometry on tumor cell suspensions to identify and visualize these TLS-associated Tfh cells within the tumor microenvironment of various human cancers. These assays take advantage of combinations of markers and molecules involved in Tfh differentiation and function.

[Consensus approach: Prior to the construction of an evaluation scale of risk constipation patients hospitalized for nursing practice]

BACKGROUND

Constipation is a frequent issue during hospitalization. Multiple causes such as the existence of irregular habits, lack of exercise as well as medical history have been identified. Drugs such as strong painkillers, central nervous system therapies and treatments of the digestive tract are a major cause of constipation. Additionally, unbalanced diet, fluid deficiency, and anxiety may aggravate constipation. The consideration of all these risk factors being under the responsibility of nurses. The difficulty to take into account such a multifactorial aetiology in nursing practice and the fact that there is no easy to use and validated tool to assess the risk of constipation in current nurse practice has led us to consider the development of a Risk Assessment scale of Constipation in Patient Hospitalized (ERCoPH) to facilitate preventive management of this trouble. We present here the first step of the elaboration of this scale, the identification of risk factors through a consensus approach after a systematic literature review.

METHODS

The key informants consensus-based approach proposed by Pineault and Daveluy is based on five steps: (1) a literature review to identify risk factors for constipation; (2) the elaboration of a questionnaire containing the factors identified in the first step; (3) pre-select a panel of experts; (4) submission the questionnaire to the panel; (5) analysis the results of the consensus survey. Only factors that received a rating>6 by at least 80 % of the experts were retained.

RESULTS

The systematic literature review identified 69 risk factors submitted to the 23 experts of the panel. Fifteen risk factors were retained after analyzing the answers of the experts. The Scientific Committee added eight risk factors because of their importance in the literature and decided to group together some factors of the same domain.

CONCLUSION

A total of 19 risk factors were selected and grouped by major class (age, physical activity, medication, social data, food/hydration, medical and surgical history and environmental data). These factors have been tested among 300 patients enrolled in different clinical settings as part of the construction and validation of ERCoPH.

TP53, STK11, and EGFR Mutations Predict Tumor Immune Profile and the Response to Anti-PD-1 in Lung Adenocarcinoma

Purpose: By unlocking antitumor immunity, antibodies targeting programmed cell death 1 (PD-1) exhibit impressive clinical results in non-small cell lung cancer, underlining the strong interactions between tumor and immune cells. However, factors that can robustly predict long-lasting responses are still needed.Experimental Design: We performed in-depth immune profiling of lung adenocarcinoma using an integrative analysis based on immunohistochemistry, flow-cytometry, and transcriptomic data. Tumor mutational status was investigated using next-generation sequencing. The response to PD-1 blockers was analyzed from a prospective cohort according to tumor mutational profiles and PD-L1 expression, and a public clinical database was used to validate the results obtained.Results: We showed that distinct combinations of STK11, EGFR, and TP53 mutations were major determinants of the tumor immune profile (TIP) and of the expression of PD-L1 by malignant cells. Indeed, the presence of TP53 mutations without co-occurring STK11 or EGFR alterations (TP53-mut/STK11-EGFR-WT), independently of KRAS mutations, identified the group of tumors with the highest CD8 T-cell density and PD-L1 expression. In this tumor subtype, pathways related to T-cell chemotaxis, immune cell cytotoxicity, and antigen processing were upregulated. Finally, a prolonged progression-free survival (PFS: HR = 0.32; 95% CI, 0.16-0.63, P < 0.001) was observed in anti-PD-1-treated patients harboring TP53-mut/STK11-EGFR-WT tumors. This clinical benefit was even more remarkable in patients with associated strong PD-L1 expression.Conclusions: Our study reveals that different combinations of TP53, EGFR, and STK11 mutations, together with PD-L1 expression by tumor cells, represent robust parameters to identify best responders to PD-1 blockade. Clin Cancer Res; 24(22); 5710-23. ©2018 AACR.

Expression of LLT1 and its receptor CD161 in lung cancer is associated with better clinical outcome

Co-stimulatory and inhibitory receptors expressed by immune cells in the tumor microenvironment modulate the immune response and cancer progression. Their expression and regulation are still not fully characterized and a better understanding of these mechanisms is needed to improve current immunotherapies. Our previous work has identified a novel ligand/receptor pair, LLT1/CD161, that modulates immune responses. Here, we extensively characterize its expression in non-small cell lung cancer (NSCLC). We show that LLT1 expression is restricted to germinal center (GC) B cells within tertiary lymphoid structures (TLS), representing a new hallmark of the presence of active TLS in the tumor microenvironment. CD161-expressing immune cells are found at the vicinity of these structures, with a global enrichment of NSCLC tumors in CD161+ CD4+ and CD8+ T cells as compared to normal distant lung and peripheral blood. CD161+ CD4+ T cells are more activated and produce Th1-cytokines at a higher frequency than their matched CD161-negative counterparts. Interestingly, CD161+ CD4+ T cells highly express OX40 co-stimulatory receptor, less frequently 4-1BB, and display an activated but not completely exhausted PD-1-positive Tim-3-negative phenotype. Finally, a meta-analysis revealed a positive association of CLEC2D (coding for LLT1) and KLRB1 (coding for CD161) gene expression with favorable outcome in NSCLC, independently of the size of T and B cell infiltrates. These data are consistent with a positive impact of LLT1/CD161 on NSCLC patient survival, and make CD161-expressing CD4+ T cells ideal candidates for efficient anti-tumor recall responses.

Development of Tools for the Selective Visualization and Quantification of TLS-Immune Cells on Tissue Sections

Tertiary lymphoid structures (TLS) are considered as genuine markers of inflammation. Their presence within inflamed tissues or within the tumor microenvironment has been associated with the local development of an active immune response. While high densities of TLS are correlated with disease severity in autoimmune diseases or during graft rejection, it has been associated with longer patient survival in many cancer types. Their efficient visualization and quantification within human tissues may represent new tools for helping clinicians in adjusting their therapeutic strategy. Some immunohistochemistry (IHC) protocols are already used in the clinic to appreciate the level of immune infiltration in formalin-fixed, paraffin-embedded (FFPE) tissues. However, the use of two or more markers may sometimes be useful to better characterize this immune infiltrate, especially in the case of TLS. Besides the growing development of multiplex labeling approaches, imaging can also be used to overcome some technical difficulties encountered during the immunolabeling of tissues with several markers.This chapter describes IHC methods to visualize in a human tissue (tumoral or not) the presence of TLS. These methods are based on the immunostaining of four TLS-associated immune cell populations, namely follicular B cells, follicular dendritic cells (FDCs), mature dendritic cells (mDCs), and follicular helper T cells (T_FH), together with non-T_FH T cells. Methodologies for subsequent quantification of TLS density are also proposed, as well as a virtual multiplexing method based on image registration using the open-source software ImageJ (IJ), aiming at co-localizing several immune cell populations from different IHC stainings performed on serial tissue sections.

Tumor-Infiltrating and Peripheral Blood T-cell Immunophenotypes Predict Early Relapse in Localized Clear Cell Renal Cell Carcinoma

Purpose: The efficacy of PD-1 checkpoint blockade as adjuvant therapy in localized clear cell renal cell carcinoma (ccRCC) is currently unknown. The identification of tumor microenvironment (TME) prognostic biomarkers in this setting may help define which patients could benefit from checkpoint blockade and uncover new therapeutic targets.Experimental Design: We performed multiparametric flow cytometric immunophenotypic analysis of T cells isolated from tumor tissue [tumor-infiltrating lymphocytes (TIL)], adjacent non-malignant renal tissue [renal-infiltrating lymphocytes (RIL)], and peripheral blood lymphocytes (PBL), in a cohort of patients (n = 40) with localized ccRCC. Immunophenotypic data were integrated with prognostic and histopathologic variables, T-cell receptor (TCR) repertoire analysis of sorted CD8⁺PD-1⁺ TILs, tumor mRNA expression, and digital quantitative immunohistochemistry.Results: On the basis of TIL phenotypic characterization, we identified three dominant immune profiles in localized ccRCC: (i) immune-regulated, characterized by polyclonal/poorly cytotoxic CD8⁺PD-1⁺Tim-3⁺Lag-3⁺ TILs and CD4⁺ICOS⁺ cells with a Treg phenotype (CD25⁺CD127^-Foxp3⁺/Helios⁺GITR⁺), that developed in inflamed tumors with prominent infiltrations by dysfunctional dendritic cells and high PD-L1 expression; (ii) immune-activated, enriched in oligoclonal/cytotoxic CD8⁺PD-1⁺Tim-3⁺ TILs, that represented 22% of the tumors; and (iii) immune-silent, enriched in TILs exhibiting RIL-like phenotype, that represented 56% of patients in the cohort. Only immune-regulated tumors displayed aggressive histologic features, high risk of disease progression in the year following nephrectomy, and a CD8⁺PD-1⁺Tim-3⁺ and CD4⁺ICOS⁺ PBL phenotypic signature.Conclusions: In localized ccRCC, the infiltration with CD8⁺PD-1⁺Tim-3⁺Lag-3⁺ exhausted TILs and ICOS⁺ Treg identifies the patients with deleterious prognosis who could benefit from adjuvant therapy with TME-modulating agents and checkpoint blockade. This work also provides PBL phenotypic markers that could allow their identification. Clin Cancer Res; 23(15); 4416-28. ©2017 AACR.

Tertiary lymphoid structures, drivers of the anti-tumor responses in human cancers

The characterization of the microenvironment of human tumors led to the description of tertiary lymphoid structures (TLS) characterized by mature dendritic cells in a T-cell zone adjacent to B-cell follicle including a germinal center. TLS represent sites of lymphoid neogenesis that develop in most solid cancers. Analysis of the current literature shows that the TLS presence is associated with a favorable clinical outcome for cancer patients, regardless of the approach used to quantify TLS and the stage of the disease. Using several approaches that combine immunohistochemistry, gene expression assays, and flow cytometry on large series of lung tumors, our work demonstrated that TLS are important sites for the initiation and/or maintenance of the local and systemic T- and B-cell responses against tumors. Surrounded by high endothelial venules, they represent a privileged area for the recruitment of lymphocytes into tumors and generation of central-memory T and B cells that circulate and limit cancer progression. TLS can be considered as a novel biomarker to stratify the overall survival risk of untreated cancer patients and as a marker of efficient immunotherapies. The induction and manipulation of cancer-associated TLS using drug agonists and/or biotherapies should open new avenues to treat cancer patients.

Randomized clinical trial of sacral nerve stimulation for refractory constipation

Background

Open studies have reported favourable results for sacral nerve stimulation in the treatment of refractory constipation. Here, its efficacy was assessed in a double-blind crossover RCT.

Methods

Patients with at least two of the following criteria were included: fewer than three bowel movements per week; straining to evacuate on more than 25 per cent of attempts; or sensation of incomplete evacuation on more than 25 per cent of occasions. Response to therapy was defined as at least three bowel movements per week and/or more than 50 per cent improvement in symptoms. Responders to an initial 3-week peripheral nerve evaluation were offered permanent implantation of a pulse generator and were assigned randomly in a crossover design to two 8-week intervals of active or sham stimulation. At the end of the two trial periods, the patients received active stimulation until the final evaluation at 1 year.

Results

Thirty-six patients (34 women; mean(s.d.) age 45(14) years) underwent peripheral nerve evaluation. Twenty responded and received a permanent stimulator. A positive response was observed in 12 of 20 and 11 of 20 patients after active and sham stimulation periods respectively (P = 0·746). Pain related to the device occurred in five patients and wound infection or haematoma in three, leading to definitive removal of the pulse generator in two patients. At 1 year, 11 of the 20 patients with an implanted device continued to respond. Stimulation had no significant effect on colonic transit time.

Conclusion

These results do not support the recommendation of permanent implantation of a pulse generator in patients with refractory constipation who initially responded to temporary nerve stimulation. Registration number: NCT01629303 (http://www.clinicaltrials.gov).

Tertiary Lymphoid Structures in Cancers: Prognostic Value, Regulation, and Manipulation for Therapeutic Intervention

Tertiary lymphoid structures (TLS) are ectopic lymphoid aggregates that reflect lymphoid neogenesis occurring in tissues at sites of inflammation. They are detected in tumors where they orchestrate local and systemic anti-tumor responses. A correlation has been found between high densities of TLS and prolonged patient's survival in more than 10 different types of cancer. TLS can be regulated by the same set of chemokines and cytokines that orchestrate lymphoid organogenesis and by regulatory T cells. Thus, TLS offer a series of putative new targets that could be used to develop therapies aiming to increase the anti-tumor immune response.

Abstract LB-273: Identity card of tumor-infiltrating regulatory T cells in the context of tertiary lymphoid structures in lung cancer patients

Regulatory T cells (Tregs) exert various suppressive mechanisms to dampen the host immune response which can help tumor cells to escape immune surveillance. However, the prognostic value of tumor-infiltrating Tregs (Ti-Tregs) is controversial. We described, tumor-associated tertiary lymphoid structures (TLS) in lung cancers, shown that they are critical for the local coordination and polarization of protective immunity and are able to imprint the behavior of intra-tumoral CD8+ T cells. The aim of the study was to determine the role of Ti-Tregs in the shaping of the local immune response in the context of TLS. We studied the differentiation, activation, immunosuppression, and immune checkpoint (ICP) status of Ti-Tregs in different areas of human lung tumors on a prospective cohort of 50 lung cancer specimens.

In lung cancer patients, CD3+FoxP3+ cells were detected in different zones of the tumor i.e. the tumor stroma (TLS and non-TLS areas) and to a lesser extend in tumor nests. They express CD4 and all markers of human Tregs. As observed for conventional CD4+ T cells, Ti-Tregs show central-memory and effector-memory phenotype. Based on the expression of activation, immunosuppression and ICP (gene and protein level), Tregs exhibit a fully activated phenotype in tumor compared to distant sites of NSCLC patients. Interestingly, Ti-Tregs display a common phenotype in TLS versus out TLS but with some key specificities regarding immune checkpoint expression.

In conclusion, the presence of several Ti-Treg subsets in lung tumor suggests they may use distinct mechanisms to exert their immunosuppressive functions in the different tumor areas.

Citation Format: Priyanka DEVI, Sylvain Leveugle, Jeremy Goc, Helene Kaplon, Claire Germain, Samantha Knockaert, Pierre Validire, Diane Damotte, Sandrine Katsahian, Wolf Herve Fridman, Catherine Sautes-Fridman, Myriam Lawand, Marie-Caroline Dieu-Nosjean. Identity card of tumor-infiltrating regulatory T cells in the context of tertiary lymphoid structures in lung cancer patients. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-273.

A high density of tertiary lymphoid structure B cells in lung tumors is associated with increased CD4+ T cell receptor repertoire clonality

T and B cell receptor (TCR and BCR, respectively) Vβ or immunoglobulin heavy chain complementarity-determining region 3 sequencing allows monitoring of repertoire changes through recognition, clonal expansion, affinity maturation, and T or B cell activation in response to antigen. TCR and BCR repertoire analysis can advance understanding of antitumor immune responses in the tumor microenvironment. TCR and BCR repertoires of sorted CD4⁺, CD8⁺ or CD19⁺ cells in tumor, non-tumoral distant tissue (NT), and peripheral compartments (blood/draining lymph node [P]) from 47 non-small cell lung cancer (NSCLC) patients (age_median = 68 y) were sequenced. The clonotype spectra were assessed among different tissues and correlated with clinical and immunological parameters. In all tissues, CD4⁺ and CD8⁺ TCR repertoires had greater clonality relative to CD19⁺ BCR. CD4⁺ T cells exhibited greater clonality in NT compared to tumor (p = 0.002) and P (p < 0.001), concentrated among older patients (age > 68). Younger patients exhibited greater CD4⁺ T cell diversity in P compared to older patients (p = 0.05), and greater CD4⁺ T cell clonality in tumor relative to P (p < 0.001), with fewer shared clonotypes between tumor and P than older patients (p = 0.04). More interestingly, greater CD4⁺ and CD8⁺ T cell clonality in tumor and P, respectively (both p = 0.05), correlated with high density of tumor-associated tertiary lymphoid structure (TLS) B cells, a biomarker of higher overall survival in NSCLC. Results indicate distinct adaptive immune responses in NSCLC, where peripheral T cell diversity is modulated by age, and tumor T cell clonal expansion is favored by the presence of TLSs in the tumor microenvironment.

Role of tumor-infiltrating regulatory T cells according to the presence of tertiary lymphoid structures in human lung cancer (IRC5P.619)

Regulatory T cells (Tregs) exert various suppressive mechanisms to dampen the host immune response which can help tumor cells to escape immune surveillance. However, the prognostic value of tumor-infiltrating Tregs (Ti-Tregs) is controversial based on the expression of FoxP3 marker in cancer patients. Here, we decipher the phenotype of Tregs infiltrating human lung cancer to determine their role in shaping the immune response against tumor cells. Our aim was to study the differentiation, activation, and immunosuppression status of Ti-Tregs in different areas of human lung tumors. Immunohistochemistry was performed on paraffin-embedded tissue sections for CD3 and FoxP3 stainings, and phenotypic analysis was carried out on fresh human lung cancer specimens (n=50) by flow cytometry. In lung cancer patients, Ti-Tregs localize in the different part of the tumor i.e. tumor nests, stroma, and tertiary lymphoid structures (TLS). Ti-Tregs are CD4+ and show central-memory and effector-memory phenotype. Interestingly, Ti-Tregs exhibit different phenotypes based on the differential expression of activation and immunosuppression molecules. In conclusion, the presence of several Ti-Treg subsets in lung tumor suggests that they may play different roles in distinct tumor areas. Thus, the next step will be to decipher the mechanisms and functions used by these Treg populations in order to manipulate them for therapeutic intervention.

Lectin-like transcript 1 is a marker of germinal center-derived B-cell non-Hodgkin's lymphomas dampening natural killer cell functions

Non-Hodgkin's lymphomas (NHLs) are malignant neoplasms which are clinically and biologically diverse. Their incidence is constantly increasing and despite treatment advances, there is a need for novel targeted therapies. Here, we identified Lectin-like transcript 1 (LLT1) as a biomarker of germinal center (GC)-derived B-cell NHLs. LLT1 identifies GC B cells in reactive tonsils and lymph nodes and its expression is maintained in B-cell NHLs which derive from GC, including Burkitt lymphoma (BL), follicular lymphoma (FL), and GC-derived diffuse large B-cell lymphoma (DLBCL). We further show that LLT1 expression by tumors dampens natural killer (NK) cell functions following interaction with its receptor CD161, uncovering a potential immune escape mechanism. Our results pinpoint LLT1 as a novel biomarker of GC-derived B-cell NHLs and as a candidate target for innovative immunotherapies.

Tertiary Lymphoid Structure-Associated B Cells are Key Players in Anti-Tumor Immunity

It is now admitted that the immune system plays a major role in tumor control. Besides the existence of tumor-specific T cells and B cells, many studies have demonstrated that high numbers of tumor-infiltrating lymphocytes are associated with good clinical outcome. In addition, not only the density but also the organization of tumor-infiltrating immune cells has been shown to determine patient survival. Indeed, more and more studies describe the development within the tumor microenvironment of tertiary lymphoid structures (TLS), whose presence has a positive impact on tumor prognosis. TLS are transient ectopic lymphoid aggregates displaying the same organization and functionality as canonical secondary lymphoid organs, with T-cell-rich and B-cell-rich areas that are sites for the differentiation of effector and memory T cells and B cells. However, factors favoring the emergence of such structures within tumors still need to be fully characterized. In this review, we survey the state of the art of what is known about the general organization, induction, and functionality of TLS during chronic inflammation, and more especially in cancer, with a particular focus on the B-cell compartment. We detail the role played by TLS B cells in anti-tumor immunity, both as antigen-presenting cells and tumor antigen-specific antibody-secreting cells, and raise the question of the capacity of chemotherapeutic and immunotherapeutic agents to induce the development of TLS within tumors. Finally, we explore how to take advantage of our knowledge on TLS B cells to develop new therapeutic tools.

Shaping of an effective immune microenvironment to and by cancer cells

A high density of intratumoral effector memory CD8+/Th1 T cells is associated with favorable prognosis in most cancers and may be induced or increased by immunotherapy. Efficient adaptive immune reactions are shaped in tumor adjacent tertiary lymphoid structures, which exhibit all characteristics of immunity generating lymphoid formations in reactive lymph nodes. Malignant tumor cells impact favorably or deleteriously their immune microenvironment if they bear genetic mutations that result in neo-antigens or by producing chemokines and cytokines that recruit lymphocytes and myeloid cells or increase inflammation and neo-angiogenesis. This intricate network of interactions results in control or escape of tumors, and its understanding will help define goals to monitor efficiency of immunotherapies.

Presence of B cells in tertiary lymphoid structures is associated with a protective immunity in patients with lung cancer

RATIONALE

It is now well established that immune responses can take place outside of primary and secondary lymphoid organs. We previously described the presence of tertiary lymphoid structures (TLS) in patients with non-small cell lung cancer (NSCLC) characterized by clusters of mature dendritic cells (DCs) and T cells surrounded by B-cell follicles. We demonstrated that the density of these mature DCs was associated with favorable clinical outcome.

OBJECTIVES

To study the role of follicular B cells in TLS and the potential link with a local humoral immune response in patients with NSCLC.

METHODS

The cellular composition of TLS was investigated by immunohistochemistry. Characterization of B-cell subsets was performed by flow cytometry. A retrospective study was conducted in two independent cohorts of patients. Antibody specificity was analyzed by ELISA.

MEASUREMENTS AND MAIN RESULTS

Consistent with TLS organization, all stages of B-cell differentiation were detectable in most tumors. Germinal center somatic hypermutation and class switch recombination machineries were activated, associated with the generation of plasma cells. Approximately half of the patients showed antibody reactivity against up to 7 out of the 33 tumor antigens tested. A high density of follicular B cells correlated with long-term survival, both in patients with early-stage NSCLC and with advanced-stage NSCLC treated with chemotherapy. The combination of follicular B cell and mature DC densities allowed the identification of patients with the best clinical outcome.

CONCLUSIONS

B-cell density represents a new prognostic biomarker for NSCLC patient survival, and makes the link between TLS and a protective B cell-mediated immunity.

Dendritic cells in tumor-associated tertiary lymphoid structures signal a Th1 cytotoxic immune contexture and license the positive prognostic value of infiltrating CD8+ T cells

Tumor-infiltrating T cells, particularly CD45RO(+)CD8(+) memory T cells, confer a positive prognostic value in human cancers. However, the mechanisms that promote a protective T-cell response in the tumor microenvironment remain unclear. In chronic inflammatory settings such as the tumor microenvironment, lymphoid neogenesis can occur to create local lymph node-like structures known as tertiary lymphoid structures (TLS). These structures can exacerbate a local immune response, such that TLS formation in tumors may help promote an efficacious immune contexture. However, the role of TLS in tumors has yet to be investigated carefully. In lung tumors, mature dendritic cells (DC) present in tumor-associated TLS can provide a specific marker of these structures. In this study, we evaluated the influence of TLS on the characteristics of the immune infiltrate in cohorts of prospective and retrospective human primary lung tumors (n = 458). We found that a high density of mature DC correlated closely to a strong infiltration of T cells that are predominantly of the effector-memory phenotype. Moreover, mature DC density correlated with expression of genes related to T-cell activation, T-helper 1 (Th1) phenotype, and cytotoxic orientation. Lastly, a high density of TLS-associated DC correlated with long-term survival, which also allowed a distinction of patients with high CD8(+) T-cell infiltration but a high risk of death. Taken together, our results show how tumors infiltrated by TLS-associated mature DC generate a specific immune contexture characterized by a strong Th1 and cytotoxic orientation that confers the lowest risk of death. Furthermore, our findings highlight the pivotal function of TLS in shaping the immune character of the tumor microenvironment, in promoting a protective immune response mediated by T cells against cancer.

Mechanisms of NK cell activation: CD4(+) T cells enter the scene

Natural killer (NK) cells are innate lymphocytes involved in immunosurveillance through their cytotoxic activity and their capacity to secrete inflammatory cytokines. NK cell activation is necessary to initiate effector functions and results from a complex series of molecular and cellular events. We review here the signals that trigger NK cells and discuss recent findings showing that, besides antigen-presenting cells, T cells can play a central role in the initiation of NK cell activation in lymph nodes.

Induction of lectin-like transcript 1 (LLT1) protein cell surface expression by pathogens and interferon-γ contributes to modulate immune responses

CD161 is a C-type lectin-like receptor expressed on human natural killer (NK) cells and subsets of T cells. CD161 has been described as an inhibitory receptor that regulates NK cell-mediated cytotoxicity and IFN-γ production. Its role on T cells has remained unclear. Studies have shown that triggering of CD161 enhances NK T cell proliferation and T cell-IFN-γ production while inhibiting TNF-α production by CD8(+) T cells. Lectin-like transcript 1 (LLT1), the ligand of CD161, was found to be expressed on Toll-like receptor (TLR)-activated plasmacytoid and monocyte-derived dendritic cells (DC) and on activated B cells. Using newly developed anti-LLT1 mAbs, we show that LLT1 is not expressed on the surface of circulating B and T lymphocytes, NK cells, monocytes, and dendritic cells but that LLT1 is up-regulated upon activation. Not only TLR-stimulated dendritic cells and B cells but also T cell receptor-activated T cells and activated NK cells up-regulate LLT1. Interestingly, IFN-γ increases LLT1 expression level on antigen-presenting cells. LLT1 is also induced on B cells upon viral infection such as Epstein-Barr virus or HIV infection and in inflamed tonsils. Finally, expression of LLT1 on B cells inhibits NK cell function but costimulates T cell proliferation or IFN-γ production, and coengagement of CD161 with CD3 increases IL-17 secretion. Altogether, our results point toward a role for LLT1/CD161 in modulating immune responses to pathogens.

Non-destructive optical monitoring of grape maturation by proximal sensing

A new, commercial, fluorescence-based optical sensor for plant constituent assessment was recently introduced. This sensor, called the Multiplex(®) (FORCE-A, Orsay, France), was used to monitor grape maturation by specifically monitoring anthocyanin accumulation. We derived the empirical anthocyanin content calibration curves for Champagne red grape cultivars, and we also propose a general model for the influence of the proportion of red berries, skin anthocyanin content and berry size on Multiplex(®) indices. The Multiplex(®) was used on both berry samples in the laboratory and on intact clusters in the vineyard. We found that the inverted and log-transformed far-red fluorescence signal called the FERARI index, although sensitive to sample size and distance, is potentially the most widely applicable. The more robust indices, based on chlorophyll fluorescence excitation ratios, showed three ranges of dependence on anthocyanin content. We found that up to 0.16 mg cm(-2), equivalent to approximately 0.6 mg g(-1), all indices increase with accumulation of skin anthocyanin content. Excitation ratio-based indices decrease with anthocyanin accumulation beyond 0.27 mg cm(-2). We showed that the Multiplex(®) can be advantageously used in vineyards on intact clusters for the non-destructive assessment of anthocyanin content of vine blocks and can now be tested on other fruits and vegetables based on the same model.

Characterization of alternatively spliced transcript variants of CLEC2D gene

Lectin-like transcript 1 (LLT1) encoded by CLEC2D gene is a C-type lectin-like molecule interacting with human CD161 (NKR-P1A) receptor expressed by natural killer cells and subsets of T cells. Using RT-PCR and sequencing, we identified several CLEC2D alternatively spliced transcript variants generated by exon skipping. In addition to the reported transcript variants 1 (LLT1) and 2, we identified a novel splice variant 4 and transcripts coding for putative soluble proteins. CLEC2D transcripts were detected primarily in hematopoietic cell lines and were found to be co-induced by the same activation signals. Although very low amounts of putative soluble CLEC2D protein isoforms could be produced by transfectants, CLEC2D isoforms 2 and 4 were efficiently expressed. By contrast to LLT1, which was detected on the cell surface, isoform 2 and 4 remained in the endoplasmic reticulum where they formed homodimers or heterodimers with LLT1. They failed to interact with CD161, leaving LLT1 as the sole ligand for this receptor. CLEC2D therefore uses gene splicing to generate protein isoforms that are structurally distinct and that have different biological activities.

New biomolecules for cancer therapy (88.2)

It has been previously demonstrated that tumor cells expressing MICA are no more able to grow in vivo due to the killing of tumor cells by both NK and CD8+ T cells.

In order to restore the presence of the MICA ligand at the surface of tumor cells, we designed biomolecules composed of MICA and an scFv (single chain fragment variable) that can recognise tumor associated antigens (TAA). The biomolecules should target tumor cells and re-direct the specific lysis of tumor cells by NK cells after interaction between NKG2D and exogenous MICA at the surface of tumor cells.

In vitro cytometry experiments showed that the biomolecules specifically bind different tumor cells expressing TAA. Using 51Cr release assay, we demonstrated that the biomolecules induce an efficient and specific killing of tumor cells mediated by NK cells or human PMBCs. In vivo, biodistribution studies showed that the biomolecules could target xenografted tumor when injected intravenously. Consequently, a protocol is investigated for therapy.

[Missed opportunities of in utero transfer of very preterm births (24-32 weeks gestation) in Aquitaine, 2003-2005]

OBJECTIVE

Describe and define the factors associated with missed opportunities of an in utero transfer (IUT), defined by by an absence of IUT where there was no counter-indication for a transfer.

MATERIALS AND METHODS

Multicentric and retrospective cohort study within the Aquitaine perinatal healthcare network from 1st January 2003 to 30th June 2005 on deliveries between 24 and 32 weeks gestation, depending on whether the woman initially followed care in level I or II facilities benefited from an IUT at a level III facility or not. associated with missed opportunities of IUT were analysed by a logistic regression.

RESULTS

Five hundred and twelve deliveries, eligible to deliver in level III facilities, were included in the study: 273 after an IUT and 239 in a level I or II maternity hospitals out of which 18% are defined as a missed opportunity of an in utero transfer. The multivariate analysis did not show a link between missed opportunities of an in utero transfer and the characteristics of maternities: status, size, level of care and distance from a level III facility. Only the delivery term appears to be linked to a missed opportunity of an in utero transfer (p=0.01): 32 weeks gestation versus 26-29 weeks gestation (RC=6.53; IC(95%): 2.00-21.25). While managing the delivery after 31 weeks gestation is considered suitable in a level IIb facility, the delivery term is no longer statistically related to a missed opportunity.

CONCLUSION

This study serves as a first analysis of the Aquitaine perinatal healthcare network. It shows that missed opportunities of IUT does not seem to be linked to characteristics of maternities but seems to be linked to deliveries after 31 weeks gestation in level IIb facilities.

Redirecting NK cells mediated tumor cell lysis by a new recombinant bifunctional protein

Natural killer (NK) cells are at the crossroad between innate and adaptive immunity and play a major role in cancer immunosurveillance. NK cell stimulation depends on a balance between inhibitory and activating receptors, such as the stimulatory lectin-like receptor NKG2D. To redirect NK cells against tumor cells, we designed bifunctional proteins able to specifically bind tumor cells and to induce their lysis by NK cells, after NKG2D engagement. To this aim, we used the 'knob into hole' heterodimerization strategy, in which 'knob' and 'hole' variants were generated by directed mutagenesis within the CH3 domain of human IgG1 Fc fragments fused to an anti-CEA or anti-HER2 scFv or to the H60 murine ligand of NKG2D, respectively. We demonstrated the capacity of the bifunctional proteins produced to specifically coat tumor cells surface with H60 ligand. Most importantly, we demonstrated that these bifunctional proteins were able to induce an NKG2D-dependent and antibody-specific tumor cell lysis by murine NK cells. Overall, the results show the possibility to redirect NK cytotoxicity to tumor cells by a new format of recombinant bispecific antibody, opening the way of potential NK cell-based cancer immunotherapies by specific activation of the NKG2D receptor at the tumor site.