Polyfunctional T cell responses in children in early stages of chronic Trypanosoma cruzi infection contrast with monofunctional responses of long-term infected adults

Background: Adults with chronic Trypanosoma cruzi exhibit a poorly functional T cell compartment, characterized by monofunctional (IFN-γ-only secreting) parasite-specific T cells and increased levels of terminally differentiated T cells. It is possible that persistent infection and/or sustained exposure to parasites antigens may lead to a progressive loss of function of the immune T cells. Methodology/Principal Findings: To test this hypothesis, the quality and magnitude of T. cruzi-specific T cell responses were evaluated in T. cruzi-infected children and compared with long-term T. cruzi-infected adults with no evidence of heart failure. The phenotype of CD4+ T cells was also assessed in T. cruzi-infected children and uninfected controls. Simultaneous secretion of IFN-γ and IL-2 measured by ELISPOT assays in response to T. cruzi antigens was prevalent among T. cruzi-infected children. Flow cytometric analysis of co-expression profiles of CD4+ T cells with the ability to produce IFN-γ, TNF-α, or to express the co-stimulatory molecule CD154 in response to T. cruzi showed polyfunctional T cell responses in most T. cruzi-infected children. Monofunctional T cell responses and an absence of CD4+TNF-α+-secreting T cells were observed in T. cruzi-infected adults. A relatively high degree of activation and differentiation of CD4+ T cells was evident in T. cruzi-infected children. Conclusions/Significance: Our observations are compatible with our initial hypothesis that persistent T. cruzi infection promotes eventual exhaustion of immune system, which might contribute to disease progression in long-term infected subjects.Fil: Albareda, María Cecilia. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: de Rissio, Ana María. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; ArgentinaFil: Tomas, Gonzalo. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; ArgentinaFil: Serjan, Alicia. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Juan A. Fernández"; ArgentinaFil: Alvarez, María Gabriela. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Viotti, Rodolfo Jorge. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Fichera, Laura Edith. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Esteva, Mónica Inés. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; ArgentinaFil: Potente, Daniel Fernando. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Armenti, Alejandro. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Tarleton, Rick L.. University of Georgia; Estados UnidosFil: Laucella, Susana Adriana. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Distinct monocyte subset phenotypes in patients with different clinical forms of chronic Chagas disease and seronegative dilated cardiomyopathy

BACKGROUND: Chronic infection with Trypanosoma cruzi leads to a constant stimulation of the host immune system. Monocytes, which are recruited in response to inflammatory signals, are divided into classical CD14hiCD16-, non-classical CD14loCD16+ and intermediate CD14hiCD16+ subsets. In this study, we evaluated the frequencies of monocyte subsets in the different clinical stages of chronic Chagas disease in comparison with the monocyte profile of seronegative heart failure subjects and seronegative healthy controls. The effect of the anti-parasite drug therapy benznidazole on monocyte subsets was also explored. METHODOLOGY/PRINCIPAL FINDINGS: The frequencies of the different monocyte subsets and their phenotypes were measured by flow cytometry. Trypanosoma cruzi-specific antibodies were quantified by conventional serological tests. T. cruzi-infected subjects with mild or no signs of cardiac disease and patients suffering from dilated cardiomyopathy unrelated to T. cruzi infection showed increased levels of non-classical CD14loCD16+ monocytes compared with healthy controls. In contrast, the monocyte profile in T. cruzi-infected subjects with severe cardiomyopathy was skewed towards the classical and intermediate subsets. After benznidazole treatment, non-classical monocytes CD14loCD16+ decreased while classical monocytes CD14hiCD16-increased. CONCLUSIONS/SIGNIFICANCE: The different clinical stages of chronic Chagas disease display distinct monocyte profiles that are restored after anti-parasite drug therapy. T. cruzi-infected subjects with severe cardiac disease displayed a profile of monocytes subsets suggestive of a more pronounced inflammatory environment compared with subjects suffering from heart failure not related to T. cruzi infection, supporting that parasite persistence might also alter cell components of the innate immune system

Inhibitory Receptors Are Expressed by Trypanosoma cruzi-Specific Effector T Cells and in Hearts of Subjects with Chronic Chagas Disease

We had formerly demonstrated that subjects chronically infected with Trypanosoma cruzi show impaired T cell responses closely linked with a process of T cell exhaustion. Recently, the expression of several inhibitory receptors has been associated with T cell dysfunction and exhaustion. In this study, we have examined the expression of the cytotoxic T lymphocyte antigen 4 (CTLA-4) and the leukocyte immunoglobulin like receptor 1 (LIR-1) by peripheral T. cruzi antigen-responsive IFN-gamma (IFN-γ)-producing and total T cells from chronically T. cruzi-infected subjects with different clinical forms of the disease. CTAL-4 expression was also evaluated in heart tissue sections from subjects with severe myocarditis. The majority of IFN-γ-producing CD4+ T cells responsive to a parasite lysate preparation were found to express CTLA-4 but considerably lower frequencies express LIR-1, irrespective of the clinical status of the donor. Conversely, few IFN-γ-producing T cells responsive to tetanus and diphtheria toxoids expressed CTLA-4 and LIR-1. Polyclonal stimulation with anti-CD3 antibodies induced higher frequencies of CD4+CTAL-4+ T cells in patients with severe heart disease than in asymptomatic subjects. Ligation of CTLA-4 and LIR-1 with their agonistic antibodies, in vitro, reduces IFN-γ production. Conversely, CTLA-4 blockade did not improved IFN-γ production in response to T. cruzi antigens. Subjects with chronic T. cruzi infection had increased numbers of CD4+LIR-1+ among total peripheral blood mononuclear cells, relative to uninfected individuals and these numbers decreased after treatment with benznidazole. CTLA-4 was also expressed by CD3+ T lymphocytes infiltrating heart tissues from chronically infected subjects with severe myocarditis. These findings support the conclusion that persistent infection with T. cruzi leads to the upregulation of inhibitory receptors which could alter parasite specific T cell responses in the chronic phase of Chagas disease

Impact of Aetiological Treatment on Conventional and Multiplex Serology in Chronic Chagas Disease

The main criterion for treatment effectiveness in Chagas Disease has been the seronegative conversion of previously reactive serology, generally achieved many years post-treatment. The lack of reliable tests to ensure parasite clearance and to examine the effect of treatment is the main difficulty in evaluating treatment for chronic Chagas disease. Decreases of conventional and non-conventional serological titers can be useful tools to monitor the early impact of treatment. We serially measured changes in antibody levels, including seronegative conversion as well as declines in titers in 53 benznidazole-treated and 89 untreated chronically T. cruzi-infected subjects. Seronegative conversion as well as decreases of titers was significantly higher in treated compared with untreated patients. A strong concordance was found between decreases of titers of conventional and non-conventional serologic tests post-treatment, reaffirming the findings. When seronegative conversion plus decreases of titers were considered altogether, the impact of treatment was higher, in a shorter follow-up period than previously considered. New tools for monitoring the effectiveness of treatment of chronic Chagas disease are necessary, and the results showed in this study is a contribution to researchers and physicians who assist patients suffering from this disease

Alternative rooting induction of semi-hardwood olive cuttings by several auxin-producing bacteria for organic agriculture systems

Southern Spain is the largest olive oil producer region in the world. In recent years organic agriculture systems have grown exponentially so that new alternative systems to produce organic olive cuttings are needed. Several bacterial isolates, namely Pantoea sp. AG9, Chryseobacterium sp. AG13, Chryseobacterium sp. CT348, Pseudomonas sp. CT364 and Azospirillum brasilense Cd (ATCC 29729), have been used to induce rooting in olive semi-hardwood cuttings of Arbequina, Hojiblanca and Picual cultivars of olive (Olea europea L). The first four strains were previously selected as auxin-producing bacteria and by their ability to promote rooting in model plants. They have been classified on the basis of their 16S rDNA gene sequence. The known auxin producer A. brasilense Cd strain has been used as a reference. The inoculation of olive cuttings was performed in two different ways: (i) by dipping cuttings in a liquid bacterial culture or (ii) by immersing them in a paste made of solid bacterial inoculant and sterile water. Under nursery conditions all of the tested bacterial strains were able to induce the rooting of olive cuttings to a similar or greater extent than the control cuttings treated with indole-3-butyric acid (IBA). The olive cultivars responded differently depending on the bacterial strain and the inoculation method. The strain that consistently gave the best results was Pantoea sp. AG9, the only one of the tested bacterial strains to express the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase. The results are also discussed in terms of potential commercial interest and nursery feasibility performance of these strains

Anales de Edafología y Fisiología Vegetal Tomo 14 Número 4

Estudio químico-edáfico del braunlehm de la Guinea continental española, por J. Mª Albareda, V. Aleíxandre y Mª del Carmen Sánchez-Calvo.--Sobre el análisis espectroquímico de la determinación simultánea de los cationes de cambio en suelos. II, por F. Burriel Martí, S. Jiménez Gómez y C. Alvarez Herrero.--Las investigaciones sobre la descomposición química de los silicatos, por Mª del Carmen Sánchez-CalvoPeer reviewe

Trypanosoma cruzi-specific IFN-γ-producing cells in chronic Chagas disease associate with a functional IL-7/IL-7R axis.

BackgroundThe severity of cardiac disease in chronic Chagas disease patients is associated with different features of T-cell exhaustion. Here, we assessed whether the ability of T cells to secrete IFN-γ in response to T. cruzi was linked to disruption in immune homeostasis and inflammation in patients with chronic Chagas disease.Methodology/principal findingsPBMCs from chronic Chagas disease patients and uninfected controls were examined for frequencies of T. cruzi-responsive IFN-γ-producing cells by ELISPOT and cellular expression and function of IL-7R using flow cytometry. Serum levels of IL-7, IL-21, IL-27, soluble IL-7R, and inflammatory cytokines were also evaluated by ELISA or CBA techniques. Patients possessing T. cruzi-specific IFN-γ-producing cells (i.e. IFN-γ producers) had higher levels of memory T cells capable of modulating the alpha chain of IL-7R and an efficient response to IL-7 compared to that in patients lacking (i.e. IFN-γ nonproducers) parasite-specific T-cell responses. IFN-γ producers also showed low levels of soluble IL-7R, high basal expression of Bcl-2 in T cells and low basal frequencies of activated CD25+ T cells. Modulation of IL-7R was inversely associated with serum IL-6 levels and positively associated with serum IL-8 levels. Circulating IL-21 and IL-27 levels were not associated with the frequency of IFN-γ producing cells but were reduced in less severe clinical forms of the disease. In vitro stimulation of PBMCs with IL-7 or IL-27 enhanced IFN-γ production in IFN-γ producers but not in IFN-γ nonproducers.Conclusions/significanceAlterations of the IL-7/IL-7R axis and in the levels of inflammatory cytokines were linked to impaired T. cruzi-specific IFN-γ production. These alterations might be responsible of the process of immune exhaustion observed in chronic Chagas disease

Anales de Edafología y Fisiología Vegetal Tomo 12 Números 7-8

Estudio del método de resistencia eléctrica para la determinación de la humedad en suelos, por José Mª Albareda, José Antonio Jiménez Salas y Julia María González Peña.-- Aplicaciones analíticas del fósforo ,radioactivo al estudio de algunos problemas agrícolas, por H. Behrens y E. Fernández-Caldas.-- Alcaloides de las papilionáceas. XIX. Contenido en alcaloides del Spartium junceum L. cultivado en Galicia, por l. Ribas y Mª C. SeoaneINFORMACIÓN: Notas: Reunión de la Sociedad Alemana de Edafología.-- Nueva Sociedad de Ciencia del Suelo.-- Catedrático de Magisterio- Doctorado Sociedad Españolade Ciencia de SueloBIBLIOGRAFÍA: C. W. Parmelec: Ceramic GlazesPeer reviewed2019-09.- CopyBook.- Libnova.- Biblioteca IC

Anales de Edafología y Fisiología Vegetal Tomo 14 Número 11

Caracterización de las arcillas del braunlehm de la Guinea continental española, por losé Mª Albareda, V . Aleixandre y Mª del Carmen Sánchez Calvo.--Aplicaciones analíticas espectrofotométricas del sistema Cr2 O7-2Cr+++. III. Determinación del contenido en materia orgánica de los suelos de la Vega de Granada, por F. Capitán García y M. Lachica Garrido.--Estudios de .competencia. I. Variaciones del .contenido proteico de la avena elevada y de la alfalfa en cultivo asociado, por Gaspar González y Erundino Alonso.--La eficacia de la actividad de la fauna del suelo desde el punto de vista edafológko, por W. L. KubienaPeer reviewe