Réponses immunitaires T dirigées contre SARS-CoV-2 : identification de la région immunogène associée à la protection contre l’infection

Une vaccination optimale et le développement d’immunothérapies contre la maladie à coronavirus COVID-19 repose sur une compréhension approfondie des réponses immunitaires déterminant la susceptibilité des individus à être infecté par le SARS-CoV-2 et à développer des formes sévères de la maladie. Afin de déterminer les corrélats immunitaire T avec une protection contre l’infection ou la réinfection par le SARS-CoV-2, nous avons caractérisé la polarité et la spécificité des réponses lymphocytaires T circulantes contre du lysat total de virus ou contre 186 peptides uniques dérivés des ORFéomes du SARS-CoV-2 et du SARS-CoV-1 chez des patients sains ou atteints de cancer (à plus haut risque de forme sévère de la COVID-19). Le ratio entre les cytokines prototypiques T helper 1 (Th1) et T helper 2 (Th2), interleukine-2 (IL-2) et interleukine-5 (IL-5), secrétées par des lymphocytes T mémoires spécifiques du SARS-CoV-2, mesuré début 2020 chez des individus non infectés par le SARS-CoV-2, est associé avec la susceptibilité de ces individus de développer une infection à SARS-CoV-2 détectable par PCR entre fin 2020 et début 2021. A noter que les lymphocytes T d’individus ayant été infectés à plusieurs reprises produisent spontanément des niveaux élevés d’IL-5 et secrète la cytokine immunosuppressive Th2 interleukine-10 en réponse au lysat de SARS-CoV-2, suggérant que les réponses Th2 dirigées contre le SARS-CoV-2 sont inadaptées. De plus les individus susceptibles à l’infection par SARS-CoV-2 présente un déficit de répertoire Th1 dirigé contre la région de la protéine Spike, hautement sujette à mutations, Receptor Binding Domain (RBD) (a.a. 331-525), et ce malgré un schéma vaccinal complet. Finalement, les vaccins actuels induisent des réponses Th1/Tc1 dirigées contre RBD chez la majorité des sujets sains qui ne présentaient pas réponses préexistantes. L’immunité T dirigée contre la séquence de référence de RBD réagit de façon croisée contre les séquences RBD des variants préoccupants (variants of concern, VOC). Ces résultats indiquent que la protection contre la COVID-19 s’appuie sur une immunité cellulaire Th1 contre la zone RBD du SARS-CoV-2, participant potentiellement à l’échappement phylogénétique du virus. La nouvelle génération de vaccins contre le SARS-CoV-2 devra permettre de développer des réponses Th1 (plutôt que Th2) de haute affinité pour le domaine RBD des variants actuels et émergeants.Optimal vaccination and immunotherapy against coronavirus disease COVID-19 relies on the in-depth comprehension of immune responses determining the individual susceptibility to be infected by SARS-CoV-2 and to develop severe disease. We characterized the polarity and specificity of circulating SARS-CoV-2-specific T cell responses against whole virus lysates or 186 unique peptides derived from the SARS-CoV-2 or SARS-CoV-1 ORFeome to determine T cell immune correlates with spontaneous (cross-reactive), SARS-CoV-2 or vaccine-induced protection against COVID-19 infection or reinfection in healthy individuals and patients with cancer, at higher risk of severe COVID-19. The ratio between the prototypic T helper 1 (TH1) cytokine, interleukin-2, and the prototypic T helper 2 (TH2) cytokine, interleukin-5 (IL-5), released from SARS-CoV-2-specific memory T cells measured in early 2020, among SARS-CoV-2-negative persons, was associated with the susceptibility of these individuals to develop PCR-detectable SARS-CoV-2 infection in late 2020 or 2021 in patients with or without cancer. Of note, T cells from individuals who recovered after SARS-CoV-2 re-infection spontaneously produced elevated levels of IL-5 and secreted the immunosuppressive TH2 cytokine interleukin-10 in response to SARS-CoV-2 lysate, suggesting that TH2 responses to SARS-CoV-2 are inadequate. Moreover, individuals susceptible to SARS-CoV-2 infection exhibited a deficit in the TH1 peptide repertoire affecting the highly mutated receptor binding domain (RBD) amino acids (331-525) of the spike protein, and this, despite complete vaccination. Finally, current vaccines successfully triggered anti-S1-RBD specific TH1/Tc1 responses in the vast majority of healthy subjects that were negative prior to immunization. Of note, T cell immunity against the S1-RBD reference strain cross-reacted against the RBD sequences of viral variants of concern. These findings indicate that COVID-19 protection relies on TH1 cell immunity against SARS-CoV-2 S1-RBD which in turn likely drives the phylogenetic escape of the virus. The next generation of COVID-19 vaccines should elicit high-avidity TH1 (rather than TH2)-like T cell responses against the RBD domain of current and emerging viral variants

Trial Watch: Oncolytic viro-immunotherapy of hematologic and solid tumors

International audienceOncolytic viruses selectively target and kill cancer cells in an immunogenic fashion, thus supporting the establishment of therapeutically relevant tumor-specific immune responses. In 2015, the US Food and Drug Administration (FDA) approved the oncolytic herpes simplex virus T-VEC for use in advanced melanoma patients. Since then, a plethora of trials has been initiated to assess the safety and efficacy of multiple oncolytic viruses in patients affected with various malignancies. Here, we summarize recent preclinical and clinical progress in the field of oncolytic virotherapy

Metabolomic analyses of COVID-19 patients unravel stage-dependent and prognostic biomarkers

Abstract The circulating metabolome provides a snapshot of the physiological state of the organism responding to pathogenic challenges. Here we report alterations in the plasma metabolome reflecting the clinical presentation of COVID-19 patients with mild (ambulatory) diseases, moderate disease (radiologically confirmed pneumonitis, hospitalization and oxygen therapy), and critical disease (in intensive care). This analysis revealed major disease- and stage-associated shifts in the metabolome, meaning that at least 77 metabolites including amino acids, lipids, polyamines and sugars, as well as their derivatives, were altered in critical COVID-19 patient’s plasma as compared to mild COVID-19 patients. Among a uniformly moderate cohort of patients who received tocilizumab, only 10 metabolites were different among individuals with a favorable evolution as compared to those who required transfer into the intensive care unit. The elevation of one single metabolite, anthranilic acid, had a poor prognostic value, correlating with the maintenance of high interleukin-10 and -18 levels. Given that products of the kynurenine pathway including anthranilic acid have immunosuppressive properties, we speculate on the therapeutic utility to inhibit the rate-limiting enzymes of this pathway including indoleamine 2,3-dioxygenase and tryptophan 2,3-dioxygenase

Gut Bacteria Composition Drives Primary Resistance to Cancer Immunotherapy in Renal Cell Carcinoma Patients

International audienceBackground: The development of immune checkpoint blockade (ICB) has revolutionized the clinical outcome of renal cell carcinoma (RCC). Nevertheless, improvement of durability and prediction of responses remain unmet medical needs. While it has been recognized that antibiotics (ATBs) decrease the clinical activity of ICB across various malignancies, little is known about the direct impact of distinct intestinal nonpathogenic bacteria (commensals) on therapeutic outcomes of ICB in RCC.Objective: To evaluate the predictive value of stool bacteria composition for ICB efficacy in a cohort of advanced RCC patients.Design, setting, and participants: We prospectively collected fecal samples from 69 advanced RCC patients treated with nivolumab and enrolled in the GETUG-AFU 26 NIVO-REN microbiota translational substudy phase 2 trial (NCT03013335) at Gustave Roussy. We recorded patient characteristics including ATB use, prior systemic therapies, and response criteria. We analyzed 2994 samples of feces from healthy volunteers (HVs). In parallel, preclinical studies performed in RCC-bearing mice that received fecal transplant (FMT) from RCC patients resistant to ICB (NR-FMT) allowed us to draw a cause-effect relationship between gut bacteria composition and clinical outcomes for ICB. The influence of tyrosine kinase inhibitors (TKIs) taken before starting nivolumab on the microbiota composition has also been assessed.Outcome measurements and statistical analysis: Metagenomic data (MG) from whole genome sequencing (WGS) were analyzed by multivariate and pairwise comparisons/ fold ratio to identify bacterial fingerprints related to ATB or prior TKI exposure and patients' therapeutic response (overall response and progression-free survival), and compared with the data from cancer-free donors.Results and limitations: Recent ATB use (n = 11; 16%) reduced objective response rates (from 28% to 9%, p < 0.03) and markedly affected the composition of the microbiota, facilitating the dominance of distinct species such as Clostridium hathewayi, which were also preferentially over-represented in stools from RCC patients compared with HVs. Importantly, TKIs taken prior to nivolumab had implications in shifting the microbiota composition. To establish a cause-effect relationship between gut bacteria composition and ICB efficacy, NR-FMT mice were successfully compensated with either FMT from responding RCC patients or beneficial commensals identified by WGS-MG (Akkermansia muciniphila and Bacteroides salyersiae).Conclusions: The composition of the microbiota is influenced by TKIs and ATBs, and impacts the success of immunotherapy. Future studies will help sharpen the role of these specific bacteria and their potential as new biomarkers.Patient summary: We used quantitative shotgun DNA sequencing of fecal microbes as well as preclinical models of fecal or bacterial transfer to study the association between stool composition and (pre)clinical outcome to immune checkpoint blockade. Novel insights into the pathophysiological relevance of intestinal dysbiosis in the prognosis of kidney cancer may lead to innovative therapeutic solutions, such as supplementation with probiotics to prevent primary resistance to therapy. (c) 2020 Published by Elsevier B.V. on behalf of European Association of Urology

Genomic Instability and Pro-Tumoral Inflammation are associated with Primary Resistance to Anti-PD1 + Anti-Angiogenesis in Malignant Pleural Mesothelioma

International audienceCancer immunotherapy combinations have recently shown to improve the overall survival of advanced mesotheliomas especially for patients responding to those treatments. We aimed to characterize the biological correlates of malignant pleural mesotheliomas primary resistance to immunotherapy and anti-angiogenics by testing the combination of pembrolizumab, an anti-PD-1 antibody, and nintedanib, a pan anti-angiogenic tyrosine kinase inhibitor (TKI), in the multi-center PEMBIB trial (NCT02856425). Thirty patients with advanced malignant pleural mesothelioma were treated and explored. Unexpectedly, we found that refractory patients were actively recruiting CD3+CD8+ cytotoxic T-cells in their tumors through CXCL9 tumor release upon treatment. However, these patients displayed high levels of somatic copy number alterations in their tumors that correlated with high blood and tumor levels of IL-6 and CXCL8. Those pro-inflammatory cytokines resulted in higher tumor secretion of VEGF and tumor enrichment in regulatory T-cells. Advanced mesothelioma should further benefit from stratified combination therapies adapted to their tumor biology

Immune system and intestinal microbiota determine efficacy of androgen deprivation therapy against prostate cancer

Background Prostate cancer (PC) responds to androgen deprivation therapy (ADT) usually in a transient fashion, progressing from hormone-sensitive PC (HSPC) to castration-resistant PC (CRPC). We investigated a mouse model of PC as well as specimens from PC patients to unravel an unsuspected contribution of thymus-derived T lymphocytes and the intestinal microbiota in the efficacy of ADT.Methods Preclinical experiments were performed in PC-bearing mice, immunocompetent or immunodeficient. In parallel, we prospectively included 65 HSPC and CRPC patients (Oncobiotic trial) to analyze their feces and blood specimens.Results In PC-bearing mice, ADT increased thymic cellularity and output. PC implanted in T lymphocyte-depleted or athymic mice responded less efficiently to ADT than in immunocompetent mice. Moreover, depletion of the intestinal microbiota by oral antibiotics reduced the efficacy of ADT. PC reduced the relative abundance of Akkermansia muciniphila in the gut, and this effect was reversed by ADT. Moreover, cohousing of PC-bearing mice with tumor-free mice or oral gavage with Akkermansia improved the efficacy of ADT. This appears to be applicable to PC patients because long-term ADT resulted in an increase of thymic output, as demonstrated by an increase in circulating recent thymic emigrant cells (sjTRECs). Moreover, as compared with HSPC controls, CRPC patients demonstrated a shift in their intestinal microbiota that significantly correlated with sjTRECs. While feces from healthy volunteers restored ADT efficacy, feces from PC patients failed to do so.Conclusions These findings suggest the potential clinical utility of reversing intestinal dysbiosis and repairing acquired immune defects in PC patients

Cancer Induces a Stress Ileopathy Depending on beta-Adrenergic Receptors and Promoting Dysbiosis that Contributes to Carcinogenesis

Gut dysbiosis has been associated with intestinal and extraintestinal malignancies, but whether and how carcinogenesis drives compositional shifts of the microbiome to its own benefit remains an open conundrum. Here, we show that malignant processes can cause ileal mucosa atrophy, with villous microvascular constriction associated with dominance of sympathetic over cholinergic signaling. The rapid onset of tumorigenesis induced a burst of REG3γ release by ileal cells, and transient epithelial barrier permeability that culminated in overt and long-lasting dysbiosis dominated by Gram-positive Clostridium species. Pharmacologic blockade of β-adrenergic receptors or genetic deficiency in Adrb2 gene, vancomycin, or cohousing of tumor bearers with tumor-free lit-termates prevented cancer-induced ileopathy, eventually slowing tumor growth kinetics. Patients with cancer harbor distinct hallmarks of this stress ileopathy dominated by Clostridium species. Hence, stress ileopathy is a corollary disease of extraintestinal malignancies requiring specific therapies. SIGNIFICANCE: Whether gut dysbiosis promotes tumorigenesis and how it controls tumor progression remain open questions. We show that 50% of transplantable extraintestinal malignancies triggered a β-adrenergic receptor–dependent ileal mucosa atrophy, associated with increased gut permeability, sustained Clostridium spp.–related dysbiosis, and cancer growth. Vancomycin or propranolol prevented cancer-associated stress ileopathy

Cancer Induces a Stress Ileopathy Depending on β-Adrenergic Receptors and Promoting Dysbiosis that Contributes to Carcinogenesis

International audienceAbstract Gut dysbiosis has been associated with intestinal and extraintestinal malignancies, but whether and how carcinogenesis drives compositional shifts of the microbiome to its own benefit remains an open conundrum. Here, we show that malignant processes can cause ileal mucosa atrophy, with villous microvascular constriction associated with dominance of sympathetic over cholinergic signaling. The rapid onset of tumorigenesis induced a burst of REG3γ release by ileal cells, and transient epithelial barrier permeability that culminated in overt and long-lasting dysbiosis dominated by Gram-positive Clostridium species. Pharmacologic blockade of β-adrenergic receptors or genetic deficiency in Adrb2 gene, vancomycin, or cohousing of tumor bearers with tumor-free littermates prevented cancer-induced ileopathy, eventually slowing tumor growth kinetics. Patients with cancer harbor distinct hallmarks of this stress ileopathy dominated by Clostridium species. Hence, stress ileopathy is a corollary disease of extraintestinal malignancies requiring specific therapies. Significance: Whether gut dysbiosis promotes tumorigenesis and how it controls tumor progression remain open questions. We show that 50% of transplantable extraintestinal malignancies triggered a β-adrenergic receptor–dependent ileal mucosa atrophy, associated with increased gut permeability, sustained Clostridium spp.–related dysbiosis, and cancer growth. Vancomycin or propranolol prevented cancer-associated stress ileopathy. This article is highlighted in the In This Issue feature, p. 87