Passive immune transfer in puppies

Le chiot nait presque agammaglobulinémique. Il acquiert une immunité passive systémique grâce au colostrum au cours des deux premiers jours de vie, La qualité du transfert d’immunité passive (appréciée par la concentration circulante des IgG à deux jours de vie) a un impact sur la santé du chiot et sur son taux de mortalité (multiplié par neuf en cas de déficit de transfert) mais interfère avec l’efficacité vaccinale. Elle est très variable entre portées ainsi qu’entre les chiots d’une même portée. La concentration des IgG du colostrum semble avoir peu d’impact sur la qualité du transfert de l’immunité passive. Ce transfert dépend davantage du délai écoulé entre la naissance et l’ingestion du colostrum du fait, du côté maternel, de la détérioration rapide de la qualité immunologique du colostrum (qui chute de plus de 50% au cours des 24 premières heures post partum) et du côté du nouveau-né, de la fermeture de la barrière intestinale (la perméabilité de l’intestin du chiot aux IgG diminue de moitié toutes les quatre heures pour devenir nulle au-delà de 12 heures de vie). L’activité sérique des gammaglutamyltranférases permet le diagnostic du déficit de transfert d’immunité passive (sensibilité : 87,5% ; spécificité : 80%). Ce déficit peut également être diagnostiqué par le calcul du taux de croissance entre la naissance et l’âge de deux jours (sensibilité : 96,3% ; spécificité : 83,1%). En l’absence de colostrum, peu de solutions sont disponibles pour faire acquérir un transfert d’immunité adéquat : la constitution d’une banque de colostrum est la solution optimale. Outre le transfert d’immunité systémique, les anticorps maternels (principalement les IgA) assurent une immunité locale, digestive dont les rôles à moyen terme pour la protection du chiot contre les entéropathogènes et, à long terme dans l’éduction du système immunitaire digestif, restent à explorer.The puppy, born without immunoglobulins G (IgG), acquires a passive systemic immunity thanks to colostrum during the two first days of life. The quality of passive immune transfer (i.e. blood IgG concentration at two days of age) impacts puppy’s health and its mortality rate but interferes with response to vaccination. It is highly variable between litters and between puppies within litters. Colostrum IgG concentration is of very limited influence on passive immune transfer, which rather depends on the time elapsed between birth and ingestion of colostrum. Deficit in passive immune transfer can be diagnosed through blood gammaglutamyltranferases assay and growth rate over the two first days of life. Colostrum banking is the optimal solution for orphan puppies. In addition to systemic passive immune transfer, maternal antibodies (mainly IgA) would provide local (digestive) immunity, ensuring mid-term protection of the puppies gut together with probably long term training of the digestive immune system

Comprehensive analysis of current approaches to inhibit regulatory T cells in cancer

CD4+CD25+Foxp3+ regulatory T cells (Treg) have emerged as a dominant T cell population inhibiting anti-tumor effector T cells. Initial strategies used for Treg-depletion (cyclophosphamide, anti-CD25 mAb…) also targeted activated T cells, as they share many phenotypic markers. Current, ameliorated approaches to inhibit Treg aim to either block their function or their migration to lymph nodes and the tumor microenvironment. Various drugs originally developed for other therapeutic indications (anti-angiogenic molecules, tyrosine kinase inhibitors,etc) have recently been discovered to inhibit Treg. These approaches are expected to be rapidly translated to clinical applications for therapeutic use in combination with immunomodulators

Effect of thrombospondin-1 inhibition by RNA interference on the potentiation of the immune reponse in a tumor context

Le cancer du sein est actuellement le cancer le plus fréquent et le plus mortel chez la femme. Malgré le fait que la prise en charge des patientes ait été améliorée dans nos sociétés occidentales au cours des dernières années, la principale cause de mortalité reste la dissémination métastatique. Force est de constater que de nombreuses stratégies thérapeutiques, comme des traitements anti-angiogéniques ou des immunothérapies ciblant des points de contrôle immunitaire, sont toujours en échec dans ce type de cancer, notamment dans les cancers du sein triple négatifs (TNBC), forme la plus agressive. L'hypoxie tumorale est un facteur de mauvais pronostic car facilitant la dissémination métastatique et inhibant la réponse immunitaire anti-tumorale. Dans ce contexte, la Thrombospondine-1 (TSP1), un anti-angiogène endogène majeur, a été décrite comme activatrice de TGFß, une cytokine immunosuppressive facilitant la transition épithélio-mésenchymateuse des cellules cancéreuses. Nous avons émis l'hypothèse que cibler la TSP1 dans les TNBC permettrait non seulement de normaliser l'angiogenèse tumorale mais aussi de faciliter la réponse immunitaire. Des analyses de bases de données publiques nous ont permis de montrer qu'une forte expression de TSP1 dans les biopsies tumorales est associée à une signature génique d'immunoéchappement et à un mauvais pronostic chez les patientes atteintes de TNBC. En accord avec ces observations, nos analyses d'immunohistochimie montrent une corrélation inverse entre l'infiltrat tumoral des lymphocytes T CD8+ et l'expression de TSP1 dans des biopsies tumorales de TNBC. Dans un modèle préclinique de TNBC, basé sur l'injection orthotopique de cellules 4T1, l'inhibition de la TSP1 par interférence ARN dans les cellules tumorales (i) augmente significativement le nombre de vaisseaux au sein des tumeurs et l'infiltration intratumorale des lymphocytes, incluant les lymphocytes T CD8, (ii) diminue la dissémination métastatique des 4T1 chez les souris immunocompétentes, mais pas chez les souris Nude, (iii) augmente la réponse aux anti-PD-1. En conclusion, nos résultats montrent que la TSP1, produite par les cellules cancéreuses de TNBC, favorise un remodelage vasculaire, inhibe l'infiltration lymphocytaire et facilite la dissémination métastatique. Cibler la TSP-1 permet de réorganiser le microenvironnement tumoral, augmentant la réponse immunitaire anti-tumorale et la réponse aux anti-PD-1. Ainsi, cette étude ouvre vers de nouvelles perspectives thérapeutiques chez les patientes atteintes de TNBC et vise à combiner des thérapies "anti-anti-angiogéniques" et des immunothérapies comme les anti-PD-1.Breast cancer is currently the most common and fatal cancer in women. The main cause of death remains metastatic dissemination despite the improvement of patient care in Western societies during the last few years. It is clear that recent therapeutic strategies, such as anti-angiogenic treatments or immunotherapies targeting immune checkpoints, are still failing to eliminate this type of cancer, especially in triple negative breast cancer (TNBC), the most aggressive form of breast cancer. At least part of the inhibition of anti-tumor immune response could be due to tumor hypoxia, a poor prognostic factor also promoting metastatic dissemination. In this context, Thrombospondin-1 (TSP1), a major endogenous antiangiogenic factor, has been described as the main activator of TGFß, an immunosuppressive cytokine facilitating the epithelial-to-mesenchymal transition of cancer cells. We hypothesized that targeting TSP1 in TNBC would not only normalize tumor angiogenesis but also facilitate the immune response. Public database analyses have shown that high TSP1 expression in tumor biopsies is associated with an immune escape gene signature and a poor prognosis in TNBC patients. Consistent with these observations, our immunohistochemistry analyses show an inverse correlation between tumor infiltration of CD8+ T cells and TSP1 expression in tumor biopsies of TNBC. In a preclinical model of TNBC, based on the orthotopic injection of 4T1 cells, the inhibition of TSP1 synthesis by RNA interference in tumor cells leads to (i) a significant increase in the number of vessels within tumors and the tumor infiltration of lymphocytes, including CD8 T cells, (ii) a decrease of metastatic dissemination of 4T1 in immunocompetent mice, but not in Nude mice, (iii) a potentiation of response to anti-PD-1. Collectively, our results show that TSP1 produced by TNBC cancer cells promotes vascular remodelling, inhibition of lymphocyte infiltration and facilitation of metastatic dissemination. Targeting TSP-1 remodelates the tumor microenvironment, increasing the anti-tumor immune response and response to anti-PD-1. Thus, this study opens up new therapeutic strategies in patients with TNBC based on combining "anti-anti-angiogenic" strategies and immunotherapies such as anti-PD-1 treatment

Thrombospondin-1 Silencing Improves Lymphocyte Infiltration in Tumors and Response to Anti-PD-1 in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is notoriously aggressive with a high metastatic potential, and targeted therapies are lacking. Using transcriptomic and histologic analysis of TNBC samples, we found that a high expression of thrombospondin-1 (TSP1), a potent endogenous inhibitor of angiogenesis and an activator of latent transforming growth factor beta (TGF-β), is associated with (i) gene signatures of epithelial–mesenchymal transition and TGF-β signaling, (ii) metastasis and (iii) a reduced survival in TNBC patients. In contrast, in tumors expressing low levels of TSP1, gene signatures of interferon gamma (IFN-γ) signaling and lymphocyte activation were enriched. In TNBC biopsies, TSP1 expression inversely correlated with the CD8+ tumor-infiltrating lymphocytes (TILs) content. In the 4T1 metastatic mouse model of TNBC, TSP1 silencing did not affect primary tumor development but, strikingly, impaired metastasis in immunocompetent but not in immunodeficient nude mice. Moreover, TSP1 knockdown increased tumor vascularization and T lymphocyte infiltration and decreased TGF-β activation in immunocompetent mice. Noteworthy was the finding that TSP1 knockdown increased CD8+ TILs and their programmed cell death 1 (PD-1) expression and sensitized 4T1 tumors to anti-PD-1 therapy. TSP1 inhibition might thus represent an innovative targeted approach to impair TGF-β activation and breast cancer cell metastasis and improve lymphocyte infiltration in tumors, and immunotherapy efficacy in TNBC

Effet de l'inhibition par ARN interférence de la thrombospondine-1 sur la potentialisation de la réponse immune dans un contexte tumoral

Breast cancer is currently the most common and fatal cancer in women. The main cause of death remains metastatic dissemination despite the improvement of patient care in Western societies during the last few years. It is clear that recent therapeutic strategies, such as anti-angiogenic treatments or immunotherapies targeting immune checkpoints, are still failing to eliminate this type of cancer, especially in triple negative breast cancer (TNBC), the most aggressive form of breast cancer. At least part of the inhibition of anti-tumor immune response could be due to tumor hypoxia, a poor prognostic factor also promoting metastatic dissemination. In this context, Thrombospondin-1 (TSP1), a major endogenous antiangiogenic factor, has been described as the main activator of TGFß, an immunosuppressive cytokine facilitating the epithelial-to-mesenchymal transition of cancer cells. We hypothesized that targeting TSP1 in TNBC would not only normalize tumor angiogenesis but also facilitate the immune response. Public database analyses have shown that high TSP1 expression in tumor biopsies is associated with an immune escape gene signature and a poor prognosis in TNBC patients. Consistent with these observations, our immunohistochemistry analyses show an inverse correlation between tumor infiltration of CD8+ T cells and TSP1 expression in tumor biopsies of TNBC. In a preclinical model of TNBC, based on the orthotopic injection of 4T1 cells, the inhibition of TSP1 synthesis by RNA interference in tumor cells leads to (i) a significant increase in the number of vessels within tumors and the tumor infiltration of lymphocytes, including CD8 T cells, (ii) a decrease of metastatic dissemination of 4T1 in immunocompetent mice, but not in Nude mice, (iii) a potentiation of response to anti-PD-1. Collectively, our results show that TSP1 produced by TNBC cancer cells promotes vascular remodelling, inhibition of lymphocyte infiltration and facilitation of metastatic dissemination. Targeting TSP-1 remodelates the tumor microenvironment, increasing the anti-tumor immune response and response to anti-PD-1. Thus, this study opens up new therapeutic strategies in patients with TNBC based on combining "anti-anti-angiogenic" strategies and immunotherapies such as anti-PD-1 treatment.Le cancer du sein est actuellement le cancer le plus fréquent et le plus mortel chez la femme. Malgré le fait que la prise en charge des patientes ait été améliorée dans nos sociétés occidentales au cours des dernières années, la principale cause de mortalité reste la dissémination métastatique. Force est de constater que de nombreuses stratégies thérapeutiques, comme des traitements anti-angiogéniques ou des immunothérapies ciblant des points de contrôle immunitaire, sont toujours en échec dans ce type de cancer, notamment dans les cancers du sein triple négatifs (TNBC), forme la plus agressive. L'hypoxie tumorale est un facteur de mauvais pronostic car facilitant la dissémination métastatique et inhibant la réponse immunitaire anti-tumorale. Dans ce contexte, la Thrombospondine-1 (TSP1), un anti-angiogène endogène majeur, a été décrite comme activatrice de TGFß, une cytokine immunosuppressive facilitant la transition épithélio-mésenchymateuse des cellules cancéreuses. Nous avons émis l'hypothèse que cibler la TSP1 dans les TNBC permettrait non seulement de normaliser l'angiogenèse tumorale mais aussi de faciliter la réponse immunitaire. Des analyses de bases de données publiques nous ont permis de montrer qu'une forte expression de TSP1 dans les biopsies tumorales est associée à une signature génique d'immunoéchappement et à un mauvais pronostic chez les patientes atteintes de TNBC. En accord avec ces observations, nos analyses d'immunohistochimie montrent une corrélation inverse entre l'infiltrat tumoral des lymphocytes T CD8+ et l'expression de TSP1 dans des biopsies tumorales de TNBC. Dans un modèle préclinique de TNBC, basé sur l'injection orthotopique de cellules 4T1, l'inhibition de la TSP1 par interférence ARN dans les cellules tumorales (i) augmente significativement le nombre de vaisseaux au sein des tumeurs et l'infiltration intratumorale des lymphocytes, incluant les lymphocytes T CD8, (ii) diminue la dissémination métastatique des 4T1 chez les souris immunocompétentes, mais pas chez les souris Nude, (iii) augmente la réponse aux anti-PD-1. En conclusion, nos résultats montrent que la TSP1, produite par les cellules cancéreuses de TNBC, favorise un remodelage vasculaire, inhibe l'infiltration lymphocytaire et facilite la dissémination métastatique. Cibler la TSP-1 permet de réorganiser le microenvironnement tumoral, augmentant la réponse immunitaire anti-tumorale et la réponse aux anti-PD-1. Ainsi, cette étude ouvre vers de nouvelles perspectives thérapeutiques chez les patientes atteintes de TNBC et vise à combiner des thérapies "anti-anti-angiogéniques" et des immunothérapies comme les anti-PD-1

Modulation of Immunity by Antiangiogenic Molecules in Cancer

In the last decades a new class of therapeutic drugs have been developed that block tumor angiogenesis. These antiangiogenic molecules, which target VEGF or VEGFR, PDGFR, and c-kit, can act not only on endothelial cells but also on immune cells. Some antiangiogenic molecules inhibit the development of immunosuppressive mechanisms developed by the tumors to escape the immune system (such as regulatory T cells, myeloid-derived suppressor cells, and immunosuppressive cytokines). These immunomodulatory effects must be characterized in detail to enable a better prescription of these treatments. In this paper we will focus on the impact of anti-angiogenic drugs on immunosuppression and their potential combination with immunotherapeutic strategies. Interestingly, immune parameters or their modulation during treatment could serve as potential biomarkers of response or resistance to anti-angiogenic therapies

Co-infection of bank voles (<em>Myodes glareolus</em>) by<em> Bartonnella spp</em> and<em> Borrelia burgdorferi sl</em> in France

National audienc

Co-infection of Borrelia afzelii and Bartonella spp. in bank voles from a suburban forest.

International audienceWe report the molecular detection of Borrelia afzelii (11%) and Bartonella spp. (56%) in 447 bank voles trapped in a suburban forest in France. Adult voles were infected by significantly more Borrelia afzelii than juveniles (p<0.001), whereas no significant difference was detected in the prevalence of Bartonella spp. between young and adult individuals (p=0.914). Six percent of the animals were co-infected by both bacteria. Analysis of the bank vole carrier status for either pathogen indicated that co-infections occur randomly (p=0.94, CI(95)=[0.53; 1.47]). Sequence analysis revealed that bank voles were infected by a single genotype of Borrelia afzelii and by 32 different Bartonella spp. genotypes, related to three known species specific to rodents (B. taylorii, B. grahamii and B. doshiae) and also two as yet unidentified Bartonella species. Our findings confirm that rodents harbor high levels of potential human pathogens; therefore, widespread surveillance should be undertaken in areas where humans may encounter rodents

IL-15 Trans-Signaling with the Superagonist RLI Promotes Effector/Memory CD8+ T Cell Responses and Enhances Antitumor Activity of PD-1 Antagonists

International audienceTumors with the help of the surrounding environment facilitate the immune suppression in patients, and immunotherapy can counteract this inhibition. Among immunotherapeutic strategies, the immunostimulatory cytokine IL-15 could represent a serious candidate for the reactivation of antitumor immunity. However, exogenous IL-15 may have a limited impact on patients with cancer due to its dependency on IL-15Rα frequently downregulated in cancer patients. In this work, we studied the antitumor activity of the IL-15 superagonist receptor-linker-IL-15 (RLI), designed to bypass the need of endogenous IL-15Rα. RLI consists of human IL-15 covalently linked to the human IL-15Rα sushi(+) domain. In a mouse model of colorectal carcinoma, RLI as a stand-alone treatment could limit tumor outgrowth only when initiated at an early time of tumor development. At a later time, RLI was not effective, coinciding with the strong accumulation of terminally exhausted programmed cell death-1 (PD-1)(high) T cell Ig mucin-3(+) CD8(+) T cells, suggesting that RLI was not able to reactivate terminally exhausted CD8(+) T cells. Combination with PD-1 blocking Ab showed synergistic activity with RLI, but not with IL-15. RLI could induce a greater accumulation of memory CD8(+) T cells and a stronger effector function in comparison with IL-15. Ex vivo stimulation of tumor-infiltrated lymphocytes from 16 patients with renal cell carcinoma demonstrated 56% of a strong tumor-infiltrated lymphocyte reactivation with the combination anti-PD-1/RLI compared with 43 and 6% with RLI or anti-PD-1, respectively. Altogether, this work provides evidence that the sushi-IL-15Rα/IL-15 fusion protein RLI enhances antitumor activity of anti-PD-1 treatment and is a promising approach to stimulate host immunity