Differing HLA types influence inhibitory receptor signalling in CMV-specific CD8+ T cells.

The dysregulated immune response to CMV constitutes a major force driving T cell immunosenescence and growing evidence suggests that it is not a benign virus in old age. We show here that the PD-1/L pathway defines a reversible defect in CMV specific CD8(+) T cell proliferative responses in both young and old individuals. More specifically, highly differentiated CD45RA(+)CD27(-) CMV-specific CD8(+) T cells exhibit a proliferative deficit compared their central and effector memory counterparts, which is reversed following PD-L blockade. However, we also report that HLA-B(∗)07/TPR specific CD8(+) T cells express higher levels of PD-1 than HLA-A(∗)02/NLV specific cells and HLA-A(∗)02 individuals show a higher proliferative response to PD-L blockade, than HLA-B(∗)07 individuals, which we postulate may be due to the differing functional avidities for these two CMV-specific CD8(+) T cells populations. Nevertheless data presented here demonstrate that CMV-specific CD8(+) T cells can be functionally enhanced by perturbation of the PD-1/L signalling pathway, whose manipulation may provide a therapeutic modality to combat age-associated immune decline

Senescence of T Lymphocytes: Implications for Enhancing Human Immunity

As humans live longer, a central concern is to find ways to maintain their health as they age. Immunity declines during ageing, as shown by the increased susceptibility to infection by both previously encountered and new pathogens and by the decreased efficacy of vaccination. It is therefore crucial to understand the mechanisms responsible for this decrease in immunity and to develop new strategies to enhance immune function in older humans. We discuss here how the induction of senescence alters leukocyte, and specifically T cell, function. An emerging concept is that senescence and nutrient sensing-signalling pathways within T cells converge to regulate functional responses, and the manipulation of these pathways may offer new ways to enhance immunity during ageing

The cellular senescence response and neuroinflammation in juvenile mice following controlled cortical impact and repetitive mild traumatic brain injury.

Traumatic brain injury (TBI) is a leading cause of disability and increases the risk of developing neurodegenerative diseases. The mechanisms linking TBI to neurodegeneration remain to be defined. It has been proposed that the induction of cellular senescence after injury could amplify neuroinflammation and induce long-term tissue changes. The induction of a senescence response post-injury in the immature brain has yet to be characterised. We carried out two types of brain injury in juvenile CD1 mice: invasive TBI using controlled cortical impact (CCI) and repetitive mild TBI (rmTBI) using weight drop injury. The analysis of senescence-related signals showed an increase in γH2AX-53BP1 nuclear foci, p53, p19ARF, and p16INK4a expression in the CCI group, 5 days post-injury (dpi). At 35 days, the difference was no longer statistically significant. Gene expression showed the activation of different senescence pathways in the ipsilateral and contralateral hemispheres in the injured mice. CCI-injured mice showed a neuroinflammatory early phase after injury (increased Iba1 and GFAP expression), which persisted for GFAP. After CCI, there was an increase at 5 days in p16INK4, whereas in rmTBI, a significant increase was seen at 35 dpi. Both injuries caused a decrease in p21 at 35 dpi. In rmTBI, other markers showed no significant change. The PCR array data predicted the activation of pathways connected to senescence after rmTBI. These results indicate the induction of a complex cellular senescence and glial reaction in the immature mouse brain, with clear differences between an invasive brain injury and a repetitive mild injury

GATA3 induces mitochondrial biogenesis in primary human CD4+ T cells during DNA damage

GATA3 is as a lineage-specific transcription factor that drives the differentiation of CD4+ T helper 2 (Th2) cells, but is also involved in a variety of processes such as immune regulation, proliferation and maintenance in other T cell and non-T cell lineages. Here we show a mechanism utilised by CD4+ T cells to increase mitochondrial mass in response to DNA damage through the actions of GATA3 and AMPK. Activated AMPK increases expression of PPARG coactivator 1 alpha (PPARGC1A or PGC1α protein) at the level of transcription and GATA3 at the level of translation, while DNA damage enhances expression of nuclear factor erythroid 2-related factor 2 (NFE2L2 or NRF2). PGC1α, GATA3 and NRF2 complex together with the ATR to promote mitochondrial biogenesis. These findings extend the pleotropic interactions of GATA3 and highlight the potential for GATA3-targeted cell manipulation for intervention in CD4+ T cell viability and function after DNA damage

The effects of positive affect and episodic future thinking on temporal discounting, and healthy food demand and choice among overweight and obese individuals: Protocol for a pilot 2x2 factorial randomized controlled study

Background: Unhealthy behaviors (eg, poor food choices) contribute to obesity and numerous negative health outcomes, including multiple types of cancer and cardiovascular and metabolic diseases. To promote healthy food choice, diet interventions should build on the dual-system model to target the regulation and reward mechanisms that guide eating behavior. Episodic future thinking (EFT) has been shown to strengthen regulation mechanisms by reducing unhealthy food choice and temporal discounting (TD), a process of placing greater value on smaller immediate rewards over larger future rewards. However, these interventions do not target the reward mechanisms that could support healthy eating and strengthen the impact of EFT-anchored programs. Increasing positive affect (PosA) related to healthy food choices may target reward mechanisms by enhancing the rewarding effects of healthy eating. An intervention that increases self-regulation regarding unhealthy foods and the reward value of healthy foods will likely have a greater impact on eating behavior compared with interventions focused on either process alone. Objective: This study aimed to introduce a protocol that tests the independent and interactive effects of EFT and PosA on TD, food choice, and food demand in overweight and obese adults. Methods: This protocol describes a factorial, randomized, controlled pilot study that employs a 2 (affective imagery: positive, neutral) by 2 (EFT: yes, no) design in which participants are randomized to 1 of 4 guided imagery intervention arms. In total, 156 eligible participants will complete 2 lab visits separated by 5 days. At visit 1, participants complete surveys; listen to the audio guided imagery intervention; and complete TD, food demand, and food choice tasks. At visit 2, participants complete TD, food demand, and food choice tasks and surveys. Participants complete a daily food frequency questionnaire between visits 1 and 2. Analyses will compare primary outcome measures at baseline, post intervention, and at follow-up across treatment arms. Results: Funding notification was received on April 27, 2017, and the protocol was approved by the institutional review board on October 6, 2017. Feasibility testing of the protocol was conducted from February 21, 2018, to April 18, 2018, among the first 32 participants. As no major protocol changes were required at the end of the feasibility phase, these 32 participants were included in the target sample of 156 participants. Recruitment, therefore, continued immediately after the feasibility phase. When this manuscript was submitted, 84 participants had completed the protocol. Conclusions: Our research goal is to develop novel, theory-based interventions to promote and improve healthy decision-making and behaviors. The findings will advance decision-making research and have the potential to generate new neuroscience and psychological research to further understand these mechanisms and their interactions. Trial Registration: ISRCTN Registry ISRCTN11704675; http://www.isrctn.com/ISRCTN11704675 (Archived by WebCite at http://www.webcitation.org/760ouOoKG) International Registered Report Identifier (IRRID): DERR1-10.2196/1226

The kinase p38 activated by the metabolic regulator AMPK and scaffold TAB1 drives the senescence of human T cells

We thank S.S. Marelli for discussions. Supported by the Medical Research Council (A.L.), the Biotechnology and Biological Science Research Council (BB/J006750/1 to A.N.A. and S.M.H.) and the Instituto de Salud Carlos III, Spain (D.E.)

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

The unmasking of Pneumocystis jiroveci pneumonia during reversal of immunosuppression: Case reports and literature review

Background: Pneumocystis jiroveci pneumonia (PCP) is an important opportunistic infection among immunosuppressed patients, especially in those infected with human immunodeficiency virus (HIV). The clinical presentation of PCP in immunosuppressed patients have been well-reported in the literature. However, the clinical importance of PCP manifesting in the setting of an immunorestitution disease (IRD), defined as an acute symptomatic or paradoxical deterioration of a (presumably) preexisting infection, which is temporally related to the recovery of the immune system and is due to immunopathological damage associated with the reversal of immunosuppressive processes, has received relatively little attention until recently. Case presentation: We aim to better define this unique clinical syndrome by reporting two cases of PCP manifesting acutely with respiratory failure during reversal of immunosuppression in non-HIV infected patients, and reviewed the relevant literature. We searched our databases for PCP cases manifesting in the context of IRD according to our predefined case definition, and reviewed the case notes retrospectively. A comprehensive search was performed using the Medline database of the National Library of Medicine for similar cases reported previously in the English literature in October 2003. A total of 28 non-HIV (excluding our present case) and 13 HIV-positive patients with PCP manifesting as immunorestitution disease (IRD) have been reported previously in the literature. During immunorestitution, a consistent rise in the median CD4 lymphocyte count (28/μL to 125/μL), with a concomitant fall in the median HIV viral load (5.5 log10 copies/ml to 3.1 log10 copies/ml) was observed in HIV-positive patients who developed PCP. A similar upsurge in peripheral lymphocyte count was observed in our patients preceding the development of PCP, as well as in other non-HIV immunosuppressed patients reported in the literature. Conclusions: PCP manifesting as IRD may be more common than is generally appreciated. Serial monitoring of total lymphocyte or CD4 count could serve as a useful adjunct to facilitate the early diagnosis and pre-emptive treatment of this condition in a wide range of immunosuppressed hosts, especially in the presence of new pulmonary symptoms and/or radiographic abnormalities compatible with the diagnosis. © 2004 Wu et al; licensee BioMed Central Ltd.published_or_final_versio