Characterization of atypical T cells generated during ex vivo expansion process for T cell-based adoptive immunotherapy.

Engineered T cell-based adoptive immunotherapies met promising success for the treatment of hematological malignancies. Nevertheless, major hurdles remain to be overcome regarding the management of relapses and the translation to solid tumor settings. Properties of T cell-based final product should be appropriately controlled to fine-tune the analysis of clinical trial results, to draw relevant conclusions, and finally to improve the efficacy of these immunotherapies. For this purpose, we addressed the existence of atypical T cell subsets and deciphered their phenotypic and functional features in an HPV16-E7 specific and MHC II-restricted transgenic-TCR-engineered T cell setting. To note, atypical T cell subsets include mismatched MHC/co-receptor CD8 or CD4 and miscommitted CD8+ or CD4+ T cells. We generated both mismatched and appropriately matched MHC II-restricted transgenic TCR on CD8 and CD4-expressing T cells, respectively. We established that CD4+ cultured T cells exhibited miscommitted phenotypic cytotoxic pattern and that both interleukin (IL)-2 or IL-7/IL-15 supplementation allowed for the development of this cytotoxic phenotype. Both CD4+ and CD8+ T cell subsets, transduced with HPV16-E7 specific transgenic TCR, demonstrated cytotoxic features after exposure to HPV-16 E7-derived antigen. Ultimately, the presence of such atypical T cells, either mismatched MHC II-restricted TCR/CD8+ T cells or cytotoxic CD4+ T cells, is likely to influence the fate of patient-infused T cell product and would need further investigation.

Response to Chemoimmunotherapy Is Associated With Expansion of Systemic Antitumor CD4 + Th1 Response in Metastatic Non-Small Cell Lung Cancer.

Limited data have reported the evolution of antitumor immune responses under chemoimmunotherapy (chemo-IO) in patients with metastatic non-small cell lung cancer. In this concise study, we performed dynamic monitoring of antitumor CD4 + T helper 1 (Th1) response in peripheral blood from 12 patients receiving a first-line chemo-IO. Tumor-reactive CD4 + Th1 cells were assessed within blood lymphocytes using interferon-gamma enzyme-linked immunospot assay to detect telomerase (TERT)-specific T cells at baseline, 3 and 12 months after treatment. An induction of circulating anti-TERT CD4 + Th1 response were found in 6 of 12 patients at 3 months after chemo-IO. In contrast, 3 patients had a substantial decrease in their preexisting response and 3 remained nonimmune responders. Among patients with chemo-IO-induced immune response, half achieved an objective clinical response and had long-lasting circulating anti-TERT CD4 + Th1 cells detected for at least 1 year. In contrast, no objective response was documented in nonimmune responders and a link between the loss of anti-TERT CD4 + Th1 responses were observed in patients with progressive disease. This preliminary work supports a relationship between the efficacy of combinatorial chemo-IO and circulating anti-TERT CD4 + Th1 responses and highlights the interest to implement blood-based monitoring of tumor-reactive CD4 + T cells that could be additional help for patient management.

Safety, Immunogenicity, and 1-Year Efficacy of Universal Cancer Peptide-Based Vaccine in Patients With Refractory Advanced Non-Small-Cell Lung Cancer: A Phase Ib/Phase IIa De-Escalation Study.

PURPOSE: Universal cancer peptide-based vaccine (UCPVax) is a therapeutic vaccine composed of two highly selected helper peptides to induce CD4+ T helper-1 response directed against telomerase. This phase Ib/IIa trial was designed to test the safety, immunogenicity, and efficacy of a three-dose schedule in patients with metastatic non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Patients with refractory NSCLC were assigned to receive three vaccination doses of UCPVax (0.25 mg, 0.5 mg, and 1 mg) using a Bayesian-based phase Ib followed by phase IIa de-escalating design. The primary end points were dose-limiting toxicity and immune response after three first doses of vaccine. Secondary end points were overall survival (OS) and progression-free survival at 1 year. RESULTS: A total of 59 patients received UCPVax; 95% had three prior lines of systemic therapy. No dose-limiting toxicity was observed in 15 patients treated in phase Ib. The maximum tolerated dose was 1 mg. Fifty-one patients were eligible for phase IIa. The third and sixth dose of UCPVax induced specific CD4+ T helper 1 response in 56% and 87.2% of patients, respectively, with no difference between three dose levels. Twenty-one (39%) patients achieved disease control (stable disease, n = 20; complete response, n = 1). The 1-year OS was 34.1% (95% CI, 23.1 to 50.4), and the median OS was 9.7 months, with no significant difference between dose levels. The 1-year progression-free survival and the median OS were 17.2% (95% CI, 7.8 to 38.3) and 11.6 months (95% CI, 9.7 to 16.7) in immune responders (P = .015) and 4.5% (95% CI, 0.7 to 30.8) and 5.6 months (95% CI, 2.5 to 10) in nonresponders (P = .005), respectively. CONCLUSION: UCPVax was highly immunogenic and safe and provide interesting 1-year OS rate in heavily pretreated advanced NSCLC.

Interplay between plasmacytoid dendritic cells and tumor-specific T cells in peripheral blood influences long-term survival in non-small cell lung carcinoma.

Plasmacytoid dendritic cells (pDCs) represent a subset of antigen-presenting cells that play an ambivalent role in cancer immunity. Here, we investigated the clinical significance of circulating pDCs and their interaction with tumor-specific T cell responses in patients with non-small cell lung cancer (NSCLC, n = 126) . The relation between intratumoral pDC signature and immune checkpoint inhibitors efficacy was also evaluated. Patients with NSCLC had low level but activated phenotype pDC compared to healthy donors. In overall population, patients with high level of pDC (pDChigh) had improved overall survival (OS) compared to patients with pDClow, median OS 30.4 versus 20.7 months (P = 0.013). This clinical benefit was only observed in stage I to III patients, but not in metastatic disease. We showed that patients harboring pDChigh profile had high amount of Th1-diffentiation cytokine interleukin-12 (IL-12) in blood and had functional T cells directed against a broad range of tumor antigens. Furthermore, a high pDC signature in the tumor microenvironment was associated with improved clinical outcome in patients treated with anti-PD-(L)1 therapy. Overall, this study showed that circulating pDChigh is associated with long-term OS in NSCLC and highlighted the predictive value of intratumor pDC signature in the efficacy of immune checkpoint inhibitors.

TIE-2 Signaling Activation by Angiopoietin 2 On Myeloid-Derived Suppressor Cells Promotes Melanoma-Specific T-cell Inhibition.

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous group of immune suppressive cells detected in several human cancers. In this study, we investigated the features and immune suppressive function of a novel subset of monocytic MDSC overexpressing TIE-2 (TIE-2+ M-MDSC), the receptor for the pro-angiogenic factor angiopoietin 2 (ANGPT2). We showed that patients with melanoma exhibited a higher circulating rate of TIE-2+ M-MDSCs, especially in advanced stages, as compared to healthy donors. The distribution of the TIE-2+ M-MDSC rate toward the melanoma stage correlated with the serum level of ANGPT2. TIE-2+ M-MDSC from melanoma patients overexpressed immune suppressive molecules such as PD-L1, CD73, TGF-ß, and IL-10, suggesting a highly immunosuppressive phenotype. The exposition of these cells to ANGPT2 increased the expression of most of these molecules, mainly Arginase 1. Hence, we observed a profound impairment of melanoma-specific T-cell responses in patients harboring high levels of TIE-2+ M-MDSC along with ANGPT2. This was confirmed by in vitro experiments indicating that the addition of ANGPT2 increased the ability of TIE-2+ M-MDSC to suppress antitumor T-cell function. Furthermore, by using TIE-2 kinase-specific inhibitors such as regorafenib or rebastinib, we demonstrated that an active TIE-2 signaling was required for optimal suppressive activity of these cells after ANGPT2 exposition. Collectively, these results support that TIE-2+ M-MDSC/ANGPT2 axis represents a potential immune escape mechanism in melanoma.

The Quality of Anti-SARS-CoV-2 T Cell Responses Predicts the Neutralizing Antibody Titer in Convalescent Plasma Donors.

Convalescent plasma therapy has been described as an attractive approach to treat critically ill patients with COVID-19 (Coronavirus disease 2019). The selection of convalescent plasma donors (CPD) is commonly based on neutralizing antibody titer. A better understanding of the quality of immune responses following COVID-19 will enable the optimization of convalescent donors' selection in convalescent plasma programs. The involvement of SARS-CoV-2 specific T cells in the induction and persistence of high affinity anti-SARS-CoV-2 neutralizing antibody is still poorly investigated. In this study, 115 CPD who presented SARS-CoV-2 and who were eligible for plasma donation were included. Comprehensive analysis of T cells together with humoral responses were performed in regards of sex, age and blood group type. High frequency of T cell responses against SARS-CoV-2 related protein such as spike glycoprotein (80.0%), nucleocapsid (NCAP) (70.4%) and membrane protein (VME1) (74.8%) were detected in CPD by ex vivo IFN-γ and TNF-α ELISpot assays. Among CPD responders, most exhibited poly-specific T cell responses (75%) defined by the ability to mount responses against at least two SARS-CoV-2 antigens. We found a positive correlation between the magnitude and the poly-specificity of anti-SARS-CoV-2 T cell responses in CPD. Notably, both the magnitude and poly-specificity of SARS-CoV-2 T cell responses were highly correlated with neutralizing antibody titer in CPD. The present study highlights that the poly-specificity and strength of SARS-CoV-2 specific T cell responses predicts neutralizing antibody titer following COVID-19. These observations show the interest to combine T cell assays and antibody titer for the selection of CPD and to a latter extend to assess COVID-19 vaccine efficacy in at-risk patients.

Naturally Occurring Telomerase-Specific CD4 T-Cell Immunity in Melanoma.

CD4 T cells play a key role in anticancer immunity. In this study, we investigate the clinical relevance of circulating CD4 T helper type 1 (Th1) response against telomerase (anti-TERT Th1 response) in patients with melanoma. The spontaneous anti-TERT Th1 response was detected in 54.5% (85/156) of patients with melanoma before treatment. The prevalence of this systemic response was inversely related to Breslow thickness >1 mm and American Joint Committee on Cancer stage ≥II (P = 0.001 and 0.032, respectively). In contrast to patients treated with targeted therapies, the anti-TERT Th1 immunity was associated with an objective response after immune checkpoint inhibitors treatment. Hence, 86% (18/21) of responder patients exhibited pre-existing anti-TERT Th1 versus 35% (6/19) in nonresponders (P = 0.001). This response was also associated with increased progression-free survival and overall survival in patients with melanoma treated with immune checkpoint inhibitors (P = 0.0008 and 0.012, respectively). Collectively, the presence of circulating anti-TERT Th1 response is inversely related to melanoma evolution and appears to be a predictive factor of response to immunotherapy. Our results highlight the interest in telomerase-specific CD4 Th1 response as a promising blood-based biomarker of immune checkpoint inhibitors therapy in melanoma.

Chemoradiation triggers antitumor Th1 and tissue resident memory-polarized immune responses to improve immune checkpoint inhibitors therapy.

BACKGROUND: Multiple synergistic combination approaches with cancer drugs are developed to overcome primary resistance to immunotherapy; however, the mechanistic rationale to combine chemoradiotherapy (CRT) with immune checkpoint inhibitors remains elusive. METHODS: This study described the immunological landscape of tumor microenvironment (TME) exposed to CRT. Tumor samples from patients with rectal cancer (n=43) treated with neoadjuvant CRT or radiotherapy were analyzed by nanostring and immunohistochemistry. Studies in mice were performed using three syngeneic tumors (TC1, CT26 and MC38). Tumor-bearing mice were treated either with platinum-based CRT, radiotherapy or chemotherapy. Anti-CTLA-4 and/or anti-Programmed Cell Death Receptor-1 (PD-1) therapy was used in combination with CRT. The therapy-exposed TME was screened by RNA sequencing and flow cytometry and tumor-infiltrating T lymphocyte functionality was evaluated by interferon (IFN)-γ ELIspot and intracellular cytokine staining. RESULTS: Front-to-front comparison analysis revealed the synergistic effect of CRT to establish a highly inflamed and Th1-polarized immune signature in the TME of patients and mice. In both settings, CRT-exposed TMEs were highly enriched in newly-infiltrated tumor-specific CD8+ T cells as well as tissue resident memory CD103+CD8+ T cells. In mice, CD8 T cells were involved in the antitumor response mediated by CRT and were primed by CRT-activated CD103+ dendritic cells. In the three tumor models, we showed that concurrent combination of CRT with a dual CTLA-4 and PD-1 blockade was required to achieve an optimal antitumor effect and to establish a broad and long-lasting protective antitumor T cell immunity. CONCLUSIONS: Our results highlight the ability of CRT to stimulate strong antitumor T-cell-mediated immunity and tissue resident memory T activation in TME, to foster immune checkpoint inhibitors action. These findings have implications in clinic for the design clinical trials combining chemoradiation with immunotherapy.

Inflammatory and immunological profile in COPD secondary to organic dust exposure.

Inflammatory response in patients with COPD secondary to organic dust exposure (OD-COPD) is poorly understood. We therefore aimed to characterize inflammatory and immune profile from peripheral blood mononuclear cells (PBMC) in a group of patients with mild-to-moderate COPD secondary to organic dust exposure (OD-COPD), tobacco smoking (T-COPD), or both. We compared T, B and NK cells distribution and inflammatory (TNF-α, Il-1ß, IL-6), type 1 (IFN-γ), type 2 (IL-4, IL-13) and type 3 (IL-17) immunity related cytokines at baseline, and after stimulation with LPS, flagellin and CD3/CD28 beads in all COPD groups. OD-COPD displayed significantly lower NK cells and CD8+ T cells compared with controls. After flagellin stimulation, T-COPD had significantly lower IL-13 levels than OD-COPD and controls (p < 0.05) whereas IFN-γ tended to be lower in OD-COPD. All COPD groups displayed higher IL-1ß and IL-17 than controls after CD3/CD28 stimulation. Inflammatory responses in OD-COPD were different from T-COPD. OD-COPD displayed higher levels of type 2 immunity related cytokines.

Immunoregulation and Clinical Implications of ANGPT2/TIE2+ M-MDSC Signature in Non-Small Cell Lung Cancer.

Myeloid-derived suppressor cells (MDSC) promote immunosuppression and are a target in the field of immuno-oncology. Accumulation of MDSCs is associated with poor prognosis and resistance to immunotherapy for several cancers. Here, we describe an accumulation of a subset of circulating monocytic MDSCs (M-MDSC) overexpressing TIE2, the receptor for angiopoietin-2 (ANGPT2), in patients with non-small cell lung cancer (NSCLC). Greater numbers of circulating TIE2+ M-MDSCs were detected in patients with NSCLC compared with healthy subjects, and this accumulation correlated with ANGPT2 concentration in blood. The presence of an ANGPT2-rich environment was associated with impairment of preexisting T-cell responses against tumor-associated antigens (TAA) in patients with NSCLC. We demonstrated that ANGPT2 sensitizes TIE2+ M-MDSCs such that these cells suppress TAA-specific T cells. In patients with NSCLC, upregulation of the ANGPT2/TIE2+ M-MDSC signature in blood was associated with a poor prognosis. Our results identify the ANGPT2/TIE2+ M-MDSC axis as a participant in tumor immune evasion that should be taken into account in future cancer immunotherapy.

Metronomic cyclophosphamide induces regulatory T cells depletion and PSA-specific T cells reactivation in patients with biochemical recurrent prostate cancer.

Biochemical recurrence (BCR) occurs in up to 40% of prostate cancer patients after prostatectomy. In our study, we performed an immune monitoring study in 20 prostate cancer patients with BCR previously treated with metronomic cyclophosphamide (mCTX). We observed a decrease of regulatory T cells (Tregs) from 2 months and this was more pronounced after 6 months of mCTX treatment. This drop of Tregs was associated with increased level of activated HLADR+ CD45R0+ T cells in peripheral blood. Furthermore, a reactivation of Th1 polarized anti-PSA T-cell response was detected in BCR patients treated with mCTX. However, dendritic cell subsets counts and activation were not influenced by the treatment. In the clinical setting, we found that PSA level control was observed in 82% (9/11) of patients with a significant diminution of Tregs after mCTX compared to 33% (3/9) in patients without Tregs decrease. In addition, 30% (6/20) of patients previously treated with mCTX remained free for androgen deprivation therapy. In conclusion, Tregs diminution and immune activation associated with PSA level control occurred after mCTX in prostate cancer patients with BCR.

Increased Levels of Interleukin-17A Exosomes in Psoriasis.

Exosomes are involved in modulating the immune system and mediating communication between cells. The aim of this study was to investigate the involvement of exosomes in psoriasis. Exosomes from patients with psoriasis were analysed by nanoparticle tracking analysis and protein expression was analysed by western blotting. The concentration of HSP70 was determined by an enzyme-linked immunosorbent assay, and concentrations of interleukin (IL)-1ß, IL-2, IL-6, IL-10, IL-17A and tumour necrosis factor alpha (TNF-α) were determined by flow cytometry. Based on the severity of psoriasis, evaluated by body surface area (≤ 10% vs. > 10%), 2 groups of patients were compared (49 with mild psoriasis and 71 with moderate-to-severe psoriasis). The number (2.52×1011 ± 2.29×1010 vs. 1.79×1011 ± 1.93×1010, p = 0.19) and size (94.44 ± 22.00 nm vs. 96.87 ± 28.30 nm, p = 0.72) of exosomes and the concentration of HSP70 in the exosomes were not significantly different in the 2 groups of patients. IL-17A exosome levels were significantly higher in patients with moderate-to-severe psoriasis compared with those with mild psoriasis (p = 0.02). There were no significant differences in levels of TNF-α, IL-1, IL-2, IL-6 and IL-10. This study shows, for the first time, the presence of circulating exosomes in patients with psoriasis. These data confirm the involvement of circulating exosomes in psoriasis, in particular in moderate-to-severe psoriasis, through IL-17A-producing exosomes.

Distinct prognostic value of circulating anti-telomerase CD4+ Th1 immunity and exhausted PD-1+/TIM-3+ T cells in lung cancer.

BACKGROUND: Despite the critical roles of Th1-polarised CD4+ T cells in cancer immunosurveillance, the translation of their potential to clinical use remains challenging. Here, we investigate the clinical relevance of circulating antitumor Th1 immunity in non-small cell lung cancer (NSCLC). METHODS: The circulating antitumor Th1 response was assessed by the ELISpot assay in 170 NSCLC patients using a mixture of HLA class II-restricted peptides from telomerase (TERT). Phenotyping of blood immune cells was performed by flow cytometry. RESULTS: TERT-reactive CD4 T-cell response was detected in 35% of NSCLC patients before any treatment. Functional analysis showed that these cells were effector memory and Th1 polarised capable to produce effector cytokines, such as IFN-γ, TNF-α and IL-2. The presence of anti-TERT Th1 response was inversely correlated with the level of exhausted PD-1+/TIM-3+CD4 T cells. The level of these two immune parameters differentially affected the survival, so that increased level of anti-TERT Th1 response and low rate of exhausted PD-1+TIM-3+CD4+ T cells were associated with a better prognosis. CONCLUSIONS: Systemic anti-TERT Th1 response plays a strong antitumor protective role in NSCLC. This study underlines the potential interest of monitoring circulating antitumor Th1 response for patients' stratification and therapy decision.

Circulating NKp46+ Natural Killer cells have a potential regulatory property and predict distinct survival in Non-Small Cell Lung Cancer.

Natural killer (NK) cells are innate effector lymphocytes widely involved in cancer immunosurveillance. In this study, we described three circulating NK cell subsets in patients with non-small cell lung cancer (NSCLC). Compared to healthy donors (HD), lower rate of the cytotoxic CD56dim CD16+ NK cells was found in NSCLC patients (76.1% vs 82.4%, P = 0.0041). In contrast, the rate of CD56bright NK cells was similar between patients and HD. We showed in NSCLC patients a higher rate of a NK cell subset with CD56dim CD16- phenotype (16.7% vs 9.9% P = 0.0001). The degranulation property and cytokines production were mainly drive by CD56dim CD16- NK cell subset in patients. Analysis of natural cytotoxicity receptors (NCRs) expression identified four distinct clusters of patients with distinct NK cell subset profiles as compared to one major cluster in HD. Notably the cluster characterized by a low circulating level of NKp46+ NK cell subsets was absent in HD. We showed that the rate of circulating NKp46+ CD56dim CD16+ NK cells influenced the patients' survival. Indeed, the median overall survival in patients exhibiting high versus low level of this NK cell subset was 16 and 27 months respectively (P = 0.02). Finally, we demonstrated that blocking NKp46 receptor in vitro was able to restore spontaneous tumor specific T cell responses in NSCLC patients. In conclusion, this study showed a distinct distribution and phenotype of circulating NK cell subsets in NSCLC. It also supports the regulatory role of NKp46+ NK cell subset in NSCLC patients.

Rapalog combined with CCR4 antagonist improves anticancer vaccines efficacy.

mTOR pathway inhibitors such as rapalogs represent a promising tool to induce functional memory CD8 T cells. In our study, we investigated the combination of temsirolimus with anticancer vaccines. Using various designs of cancer vaccines (short and long peptides or the B subunit of Shiga toxin as an antigen delivery vector) and tumor models (melanoma, lung and colon cancer), we showed that the administration of temsirolimus efficiently decreased tumor growth and enhanced tumor-specific CD8 T-cell responses induced by vaccination. Furthermore, tumor-specific CD8 T cells induced by the bi-therapy (vaccine + temsirolimus) exhibit phenotypic characteristics of central memory (CD127+ CD62L+ ) CD8 T cells compared to vaccination alone. We demonstrated that regulatory CD4 T cells (Tregs ) expansion in vivo limits the efficacy of the bi-therapy by altering the antitumor CD8 T-cell responses. Finally, the use of a small molecule CCR4 antagonist to prevent Tregs induction considerably improved the efficacy of the bi-therapy by enhancing CD8 T cells-mediated antitumor immunity. Taken together, our study highlights the potential interest of combining cancer vaccines with drugs that promote memory CD8 T cells and inhibit Tregs .

SALL4 oncogene is an immunogenic antigen presented in various HLA-DR contexts.

Purpose: To investigate the immunoprevalence of SALL4-derived peptides in healthy volunteers and cancer patients. Experimental Design: A multistep approach including prediction algorithms was used to design in silico SALL4-derived peptides theoretically able to bind on common HLA-DR and HLA-A/B molecules. The presence of T-cell responses after a long term T-cell assay (28 days) against SALL4 was monitored in 14 healthy donors and the presence of T-cell responses after a short term T-cell assay (10 days) was monitored in 67 cancer patients using IFN-γ ELISPOT assay. A T-cell clone specific for the immunoprevalent A18 K-derived peptide was isolated, characterized and used as a tool to characterize the natural processing of A18 K. Results: A SALL4 specific T-cell repertoire was present in healthy donors (8/14) and cancer patients (29/67) after short term T-cell assay. We further identified two immunoprevalant SALL4-derived peptides, R18 A and A18 K, which bind MHC-class II. In parallel, an A18 K specific Th1 clone recognized monocyte derived Dendritic Cell (moDC) loaded with SALL4 containing cell lysate. The level of IFN-γ secreted by specific T-cell clone was greater in presence of moDC loaded with SALL4 containing cell lysate (49.23 ± 14.02%) than with moDC alone (18.03 ± 3.072%) (p = 0.0477) Conclusion: These results show for the first time immunogenicity of SALL4 oncogenic protein-derived peptides, especially A18 K and R18 A peptides and make them potential targets for personalized medicine. Thus, SALL4 possess major characteristics of a tumor antigen.

Heparan Sulfate Proteoglycans Promote Telomerase Internalization and MHC Class II Presentation on Dendritic Cells.

Telomerase is a prototype-shared tumor Ag and represents an attractive target for anticancer immunotherapy. We have previously described promiscuous and immunogenic HLA-DR-restricted peptides derived from human telomerase reverse transcriptase (hTERT) and referred as universal cancer peptide (UCP). In nonsmall cell lung cancer, the presence of spontaneous UCP-specific CD4 T cell responses increases the survival of chemotherapy-responding patients. However, the precise mechanisms of hTERT's uptake, processing, and presentation on MHC-II molecules to stimulate CD4 T cells are poorly understood. In this work, by using well-characterized UCP-specific CD4 T cell clones, we showed that hTERT processing and presentation on MHC-II involve both classical endolysosomal and nonclassical cytosolic pathways. Furthermore, to our knowledge, we demonstrated for the first time that hTERT's internalization by dendritic cells requires its interaction with surface heparan sulfate proteoglycans. Altogether, our findings provide a novel mechanism of tumor-specific CD4 T cell activation and will be useful for the development of novel cancer immunotherapies that harness CD4 T cells.

Rapalogs Efficacy Relies on the Modulation of Antitumor T-cell Immunity.

The rapalogs everolimus and temsirolimus that inhibit mTOR signaling are used as antiproliferative drugs in several cancers. Here we investigated the influence of rapalogs-mediated immune modulation on their antitumor efficacy. Studies in metastatic renal cell carcinoma patients showed that everolimus promoted high expansion of FoxP3 (+)Helios(+)Ki67(+) regulatory CD4 T cells (Tregs). In these patients, rapalogs strongly enhanced the suppressive functions of Tregs, mainly in a contact-dependent manner. Paradoxically, a concurrent activation of spontaneous tumor-specific Th1 immunity also occurred. Furthermore, a high rate of Eomes(+)CD8(+) T cells was detected in patients after a long-term mTOR inhibition. We found that early changes in the Tregs/antitumor Th1 balance can differentially shape the treatment efficacy. Patients presenting a shift toward decreased Tregs levels and high expansion of antitumor Th1 cells showed better clinical responses. Studies conducted in tumor-bearing mice confirmed the deleterious effect of rapalogs-induced Tregs via a mechanism involving the inhibition of antitumor T-cell immunity. Consequently, the combination of temsirolimus plus CCR4 antagonist, a receptor highly expressed on rapalogs-exposed Tregs, was more effective than monotherapy. Altogether, our results describe for the first time a dual impact of host adaptive antitumor T-cell immunity on the clinical effectiveness of rapalogs and prompt their association with immunotherapies. Cancer Res; 76(14); 4100-12. ©2016 AACR.