IL-21 restricts virus-driven Treg cell expansion in chronic LCMV infection

Foxp3+ regulatory T (Treg) cells are essential for the maintenance of immune homeostasis and tolerance. During viral infections, Treg cells can limit the immunopathology resulting from excessive inflammation, yet potentially inhibit effective antiviral T cell responses and promote virus persistence. We report here that the fast-replicating LCMV strain Docile triggers a massive expansion of the Treg population that directly correlates with the size of the virus inoculum and its tendency to establish a chronic, persistent infection. This Treg cell proliferation was greatly enhanced in IL-21R-/- mice and depletion of Treg cells partially rescued defective CD8+ T cell cytokine responses and improved viral clearance in some but not all organs. Notably, IL-21 inhibited Treg cell expansion in a cell intrinsic manner. Moreover, experimental augmentation of Treg cells driven by injection of IL-2/anti-IL-2 immune complexes drastically impaired the functionality of the antiviral T cell response and impeded virus clearance. As a consequence, mice became highly susceptible to chronic infection following exposure to low virus doses. These findings reveal virus-driven Treg cell proliferation as potential evasion strategy that facilitates T cell exhaustion and virus persistence. Furthermore, they suggest that besides its primary function as a direct survival signal for antiviral CD8+ T cells during chronic infections, IL-21 may also indirectly promote CD8+ T cell poly-functionality by restricting the suppressive activity of infection-induced Treg cells.

Allocuzione agli alunni del collegio israelitico Colonna e Finzi di Torino in occasione della distribuzione de'premii il 21 Novembre 1847 : letta

dall Lelio Cantoni

Dei suoni musicali : lettura fatta nelle sala del Circolo Cittadoni in Modena il 21 marzo 1868 /

University of Illinois bookplate: "From the library of Conte Antonio Cavagna Sangiuliani di Gualdana Lazelada di Bereguardo, purchased 1921".

Rendiconto dell'adunanza generale dei soci del Pio Istituto di Patronato pei carcerati e liberati dal carcere dell provincia di Milano, tenutasi il 21 novembre 1861.

University of Illinois bookplate: "From the library of Conte Antonio Cavagna Sangiuliani di Gualdana Lazelada di Bereguardo purchased 1921".

Efecto de la terapia autóloga con linfocitos T CD8+ estimulados con antígeno tumoral total E IL-21 en caninos con tumor venéreo transmisible

La Organización Mundial de la Salud declaro que el cáncer es una de las principales causas de muerte en el mundo, para el 2012 se presentó un total de 8.2 millones de defunciones. A pesar de la gran cantidad de recursos invertidos en investigación, la tasa de mortalidad no ha sido disminuida, por lo tanto es necesario el desarrollo de nuevas terapias efectivas contra el cáncer. Desde sus inicios, en el campo de la inmunoterapia se han realizado numerosos ensayos en humanos con cáncer y en modelos animales, obteniendo algunos casos de regresión tumoral completa. En el presente trabajo se evaluó el efecto de la terapia autóloga en perros inoculados experimentalmente con Tumor Venéreo Transmisible (TVT). Se inoculó12 hembras de raza mixta con TVT (1x108 células) intragenital, una vez que el tumor alcanzo un volumen de 10cm 3 , se colectó una biopsia con la cual se extrajo el antígeno tumoral total (300 µg/mL) el cual fue agregado (30µg/mL) en cultivos de células dendríticas inmaduras. Linfocitos totales obtenidos del mismo paciente y CPAs (CD80+ 80.3%, CD83+ 76.4%, DLA II 86.5%) cargadas con antígeno tumoral fueron co-cultivados en presencia de estímulos con IL-21 (50ng/mL) o IL-2 (20ng/mL), posterior a la activación de los linfocitos (746.88 pg/mL IFNȖ), las células T CD8+ específicos de tumor fueron separadas por selección negativa (Dynabeads Untouched) con un 82.6% de pureza para finalmente ser expandidas con OKT3. Se llevó a cabo un ensayo de in vitro de la citotoxicidad de los Linfocitos T CD8+ específicos de tumor contra las células de TVT, obteniendo 100% de lisis de la célula tumoral cultivada en presencia de linfocitos CD8+ específicos de tumor estimulados con IL-21 y un 90% de citotoxicidad tumoral cuando los CD8+ fueron específicos pero estimulados con IL-2, cuando los CD8+ no fueron específicos de tumor el porcentaje de citotoxicidad fue muy poco (10%). In vivo el grupo 1 fue tratado con terapia autóloga, linfocitos T CD8+ (5x107 célulaspor ciclo) específicos de tumor estimulados con IL-21 y aplicados en 3 ciclos en intervalos de 2 semanas. Como grupos control se utilizaron perros con tumor sin tratamiento (grupo 2), perros con tumor tratados con suero glucosado (grupo 3) y perros con tumor tratados con transfusión sanguínea autóloga (grupo 4). Después de la terapia autóloga la inmunidad celular (CD4+ y CD8+ ) e IFNȖ fue incrementada observando regresión tumoral en los perros del grupo 1. Estos resultados indican que la terapia autóloga es eficaz en la destrucción del TVT.

Transcription Factor NFATc2 Controls the Emergence of Colon Cancer Associated with IL-6-Dependent Colitis.

NFAT transcription factors control T-cell activation and function. Specifically, the transcription factor NFATc2 affects the regulation of cell differentiation and growth and plays a critical role in the development of colonic inflammation. Here, we used an experimental model of colitis-associated colorectal carcinoma to investigate the contribution of NFATc2 to the promotion of colonic tumors. Compared with wild-type animals that readily presented with multiple colon tumors, NFATc2-deficient mice were protected from tumor development. This observed decrease in colonic tumor progression was associated with reduced endoscopic inflammation, increased apoptosis of lamina propria T lymphocytes, and significantly reduced levels of the critical proinflammatory cytokines interleukin (IL)-21 and IL-6. Administration of hyper IL-6 abrogated protection from tumor progression in NFATc2-knockout mice and restored tumor incidence to control levels. Taken together, our findings highlight a pivotal role for NFATc2 in the establishment of inflammation-associated colorectal tumors mediated by control of IL-6 expression. Cancer Res; 72(17); 4340-50. ©2012 AACR.

IL-27 Induces Th17 Differentiation in the Absence of STAT1 Signaling.

It is known that differentiation of Th17 cells is promoted by activation of STAT3 and inhibited by activation of STAT1. Although both transcription factors are activated by several cytokines, including IL-6, IL-21, and IL-27, each of these cytokines has a very different effect on Th17 differentiation, ranging from strong induction (IL-6) to strong inhibition (IL-27). To determine the molecular basis for these differences, we measured STAT3 and STAT1 activation profiles for IL-6, IL-21, and IL-27, as well as for cytokine pairs over time. We found that the ratio of activated STAT3/activated STAT1 is crucial in determining whether cytokines promote or inhibit Th17 differentiation. IL-6 and IL-21 induced p-STAT3/p-STAT1 ratios > 1, leading to the promotion of Th17 differentiation, whereas IL-27 or IL-6+IL-27 induced p-STAT3/p-STAT1 ratios < 1, resulting in inhibition of Th17 differentiation. Consistent with these findings, we show that IL-27 induces sufficient p-STAT3 to promote Th17 differentiation in the absence of STAT1. Furthermore, IL-27-induced STAT1-deficient T cells were indistinguishable from bona fide highly proinflammatory Th17 cells because they induced severe experimental autoimmune encephalomyelitis upon adoptive transfer. Our results suggest that the ratio of p-STAT3/p-STAT1 induced by a cytokine or cytokine pairs can be used to predict whether they induce a competent Th17-differentiation program.

Investigating the thymopoiesis stimulating property of interleukin-21 in aging mice

La vaccination est largement utilisée pour la génération de lymphocytes T spécifiques contre les tumeurs. Malheureusement, cette stratégie n'est pas adaptée aux personnes âgées car leur thymus régresse avec l'âge conduisant ainsi à une baisse dans la production de cellules T et à l'accumulation de cellules immunitaires âgées ayant des défauts liés à leurs stimulations. Comme il a été démontré auparavant que L’IL-21 est capable d’induire des fonctions thymiques, nous avons émis l’hypothèse que l’injection d’IL-21 à des souris âgées stimulera la thymopoïèse. Nos résultats montrent que l’administration de l’IL-21 augmente le nombre absolu de thymocytes chez les souris âgées et augmente la migration de ces cellules vers la périphérie ou ils contribuent à la diversité du TCR. De plus les cellules T en périphérie expriment un niveau plus élevé de miR181-a, et par conséquent moins de phosphatase comme SHP2, DUSP5/6 qui inhibent le TCR. En vaccinant des souris âgées avec le peptide Trp2, les souris traitées avec l’IL-21 montrent un retard dans la croissance des cellules B16 tumorales. Cette étude montre que l’IL-21 pourrait être utilisé comme stratégie pour le rétablissement du systeme immunitaire chez les personnes âgées.

Investigating the thymopoiesis stimulating property of interleukin-21 in aging mice

La vaccination est largement utilisée pour la génération de lymphocytes T spécifiques contre les tumeurs. Malheureusement, cette stratégie n'est pas adaptée aux personnes âgées car leur thymus régresse avec l'âge conduisant ainsi à une baisse dans la production de cellules T et à l'accumulation de cellules immunitaires âgées ayant des défauts liés à leurs stimulations. Comme il a été démontré auparavant que L’IL-21 est capable d’induire des fonctions thymiques, nous avons émis l’hypothèse que l’injection d’IL-21 à des souris âgées stimulera la thymopoïèse. Nos résultats montrent que l’administration de l’IL-21 augmente le nombre absolu de thymocytes chez les souris âgées et augmente la migration de ces cellules vers la périphérie ou ils contribuent à la diversité du TCR. De plus les cellules T en périphérie expriment un niveau plus élevé de miR181-a, et par conséquent moins de phosphatase comme SHP2, DUSP5/6 qui inhibent le TCR. En vaccinant des souris âgées avec le peptide Trp2, les souris traitées avec l’IL-21 montrent un retard dans la croissance des cellules B16 tumorales. Cette étude montre que l’IL-21 pourrait être utilisé comme stratégie pour le rétablissement du systeme immunitaire chez les personnes âgées.

IL-10-producing Regulatory B Cell Development in Human Autoimmune Disease

B cell abnormalities contribute to the development and progress of autoimmune disease. Traditionally, the role of B cells in autoimmune disease was thought to be predominantly limited to the production of autoantibodies. Nevertheless, in addition to autoantibody production, B cells have other functions potentially relevant to autoimmunity. Such functions include antigen presentation to and activation of T cells, expression of costimulatory molecules and cytokine production. Recently, the ability of B cells to negatively regulate cellular immune responses and inflammation has been described and the concept of “regulatory B cells” has emerged. A variety of cytokines produced by regulatory B cell subsets have been reported with interleukin-10 (IL-10) being the most studied. IL-10-producing regulatory B cells predominantly localize within a rare CD1dhiCD5+ B cell subset in mice and the CD24hiCD27+ B cell subset in adult humans. This specific IL-10-producing subset of regulatory B cells have been named “B10 cells” to highlight that the regulatory function of these rare B cells is primarily mediated by IL-10, and to distinguish them from other regulatory B cell subsets that regulate immune responses through different mechanisms. B10 cells have been studies in a variety of animal models with autoimmune disease and clinical settings of human autoimmunity. There are many unsolved questions related to B10 cells including their surface phenotype, their origin and development in vivo, and their role in autoimmunity.

In Chapter 3 of this dissertation, the role of the B cell receptor (BCR) in B10 cell development is highlighted. First, the BCR repertoire of mouse peritoneal cavity B10 cells is examined by single cell sequencing; peritoneal cavity B10 cells have clonally diverse germline BCRs that are predominantly unmutated. Second, mouse B10 cells are shown to have higher frequencies of λ+ BCRs compared to non-B10 cells which may indicate the involvement of BCR light chain editing early in the process of B10 cell development in vivo. Third, human peripheral blood B10 cells are examined and are also found to express higher frequencies of λ chains compared to non-b10 cells. Therefore, B10 cell BCRs are clonally diverse and enriched for unmutated germline sequences and λ light chains.

In Chapter 4 of this dissertation, B10 cells are examined in the healthy developing human across the entire age range of infancy, childhood and adolescence, and in a large cohort of children with autoimmunity. The study of B10 cells in the developing human documents a massive transient expansion during middle childhood when up to 30% of blood B cells were competent to produce IL-10. The surface phenotype of pediatric B10 cells was variable and reflective of overall B cell development. B10 cells down-regulated CD4+ T cell interferon-gamma (IFN-γ) production through IL-10-dependent pathways and IFN-γ inhibited whereas interleukin-21 (IL-21) promoted B cell IL-10 competency in vitro. Children with autoimmunity had a contracted B10 cell compartment, along with increased IFN-γ and decreased IL-21 serum levels compared to age-matched healthy controls. The decreased B10 cell frequencies and numbers in children with autoimmunity may be partially explained by the differential regulation of B10 cell development by IFN-γ and IL-21 and alterations in serum cytokine levels. The age-related changes of the B10 cell compartment during normal human development provide new insights into immune tolerance mechanisms involved in inflammation and autoimmunity.

These studies collectively demonstrate that BCR signals are the most important early determinant of B10 cell development in vivo, that human B10 cells are not a surface phenotype defined developmental B cell subset but a functionally defined regulatory B cell subset that regulates CD4+ T IFN-γ production through IL-10-dependent pathways and that human B10 cell development can be regulated by soluble factors in vivo such as the cytokine milieu. The findings of these studies provide new insights into immune tolerance mechanisms involved in human autoimmunity and the potent effects of IL-21 on human B cell IL-10 competence in vitro open new horizons in the development of autologous B10 cell-based therapies as an approach to treat human autoimmune disease in the future.

Al lado, itinerario de atención compartida : Demencias, Alzheimer

En la port.: Confeafa. Publicado en la página web de la Consejería de Salud: www.juntadeandalucia.es/salud (Consejería de Salud / Ciudadanía / Nuestra Salud / Vida sana / Dependencia / AL LADO: Itinerario de Atención Compartida Demencias / Alzheimer / AL LADO. Itinerario de Atención Compartida Demencias / Alzheimer)

Prevención y detección precoz del maltrato infantil: revisión de estrategias e intervenciones desde los servicios sanitarios

Publicado en la plataforma de la Red Sabia (Red de Salud y Buen Trato a la Infancia y la Adolescencia. http://www.redsabia.org/) de la Consejería de Igualdad, Salud y Políticas Sociales

Follicular helper T cells serve as the major CD4 T cell compartment for HIV-1 infection, replication, and production.

In the present study, we have investigated the distribution of HIV-specific and HIV-infected CD4 T cells within different populations of memory CD4 T cells isolated from lymph nodes of viremic HIV-infected subjects. Four memory CD4 T cell populations were identified on the basis of the expression of CXCR5, PD-1, and Bcl-6: CXCR5(-)PD-1(-)Bcl-6(-), CXCR5(+)PD-1(-)Bcl-6(-), CXCR5(-)PD-1(+)Bcl-6(-), and CXCR5(+)PD-1(+)Bcl-6(+). On the basis of Bcl-6 expression and functional properties (IL-21 production and B cell help), the CXCR5(+)PD-1(+)Bcl-6(+) cell population was considered to correspond to the T follicular helper (Tfh) cell population. We show that Tfh and CXCR5(-)PD-1(+) cell populations are enriched in HIV-specific CD4 T cells, and these populations are significantly increased in viremic HIV-infected subjects as compared with healthy subjects. The Tfh cell population contained the highest percentage of CD4 T cells harboring HIV DNA and was the most efficient in supporting productive infection in vitro. Replication competent HIV was also readily isolated from Tfh cells in subjects with nonprogressive infection and low viremia (<1,000 HIV RNA copies). However, only the percentage of Tfh cells correlated with the levels of plasma viremia. These results demonstrate that Tfh cells serve as the major CD4 T cell compartment for HIV infection, replication, and production.

Role of Tyk-2 in Th9 and Th17 cells in allergic asthma.

In a murine model of allergic asthma, we found that Tyk-2((-/-)) asthmatic mice have induced peribronchial collagen deposition, mucosal type mast cells in the lung, IRF4 and hyperproliferative lung Th2 CD4(+) effector T cells over-expressing IL-3, IL-4, IL-5, IL-10 and IL-13. We also observed increased Th9 cells expressing IL-9 and IL-10 as well as T helper cells expressing IL-6, IL-10 and IL-21 with a defect in IL-17A and IL-17F production. This T helper phenotype was accompanied by increased SOCS3 in the lung of Tyk-2 deficient asthmatic mice. Finally, in vivo treatment with rIL-17A inhibited local CD4(+)CD25(+)Foxp3(+) T regulatory cells as well as Th2 cytokines without affecting IL-9 in the lung. These results suggest a role of Tyk-2 in different subsets of T helper cells mediated by SOCS3 regulation that is relevant for the treatment of asthma, cancer and autoimmune diseases.