Eimeria vermiformis Infection model of Murine small intestine

Copyright © 2018 The Authors; exclusive licensee Bio-protocol LLC.Eimeria vermiformis is a tissue specific, intracellular protozoan that infects the murine small intestinal epithelia, which has been widely used as a coccidian model to study mucosal immunology. This mouse infection model is valuable to investigate the mechanisms of host protection against primary and secondary infection in the small intestine. Here, we describe the generation of an E. vermiformis stock solution, preparation of sporulated E. vermiformis to infect mice and determination of oocysts burden. This protocol should help to establish a highly reproducible natural infection challenge model to study immunity in the small intestine. The information obtained from using this mouse model can reveal fundamental mechanisms of interaction between the pathogen and the immune response, e.g., provided by intraepithelial lymphocytes (IEL) at the basolateral site of epithelial cells but also a variety of other immune cell populations present in the gut.This work was supported by the European Union H2020 ERA project (No. 667824– EXCELLtoINNOV) for work in the Veldhoen laboratory and Fundação para a Ciência e a Tecnologia (FCT) Studentship SFRH/BD/131605/2017 to P.F-C.info:eu-repo/semantics/publishedVersio

Elucidating different pattern of immunoregulation in BALB/c and C57BL/6 mice and their F1 progeny

© The Author(s) 2021. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ .Helminths are large multicellular parasites that infect one quarter of the human population. To prolong their survival, helminths suppress the immune responses of their hosts. Strongyloides ratti delays its expulsion from the gut by induction of regulatory circuits in a mouse strain-specific manner: depletion of Foxp3+ regulatory T cells (Treg) improves the anti-S. ratti immunity in BALB/c but not in C57BL/6 mice. In the current study we compare the hierarchy of immunoregulatory pathways in BALB/c, C57BL/6 mice and their F1 progeny (BALB/c × C57BL/6). Using multicolor flow cytometry, we show that S. ratti induces a distinct pattern of inhibitory checkpoint receptors by Foxp3+ Treg and Foxp3- T cells. Intensity of expression was highest in C57BL/6 and lowest in BALB/c mice, while the F1 cross had an intermediate phenotype or resembled BALB/c mice. Treg subsets expanded during infection in all three mouse strains. Similar to BALB/c mice, depletion of Treg reduced intestinal parasite burden and increased mucosal mast cell activation in S. ratti-infected F1 mice. Our data indicate that Treg dominate the regulation of immune responses in BALB/c and F1 mice, while multiple regulatory layers exist in C57BL/6 mice that may compensate for the absence of Treg.Open Access funding enabled and organized by Projekt DEAL.info:eu-repo/semantics/publishedVersio

M. tuberculosis Reprograms Hematopoietic Stem Cells to Limit Myelopoiesis and Impair Trained Immunity

A greater understanding of hematopoietic stem cell (HSC) regulation is required for dissecting protective versus detrimental immunity to pathogens that cause chronic infections such as Mycobacterium tuberculosis (Mtb). We have shown that systemic administration of Bacille Calmette-Guérin (BCG) or ß-glucan reprograms HSCs in the bone marrow (BM) via a type II interferon (IFN-II) or interleukin-1 (IL1) response, respectively, which confers protective trained immunity against Mtb. Here, we demonstrate that, unlike BCG or ß-glucan, Mtb reprograms HSCs via an IFN-I response that suppresses myelopoiesis and impairs development of protective trained immunity to Mtb. Mechanistically, IFN-I signaling dysregulates iron metabolism, depolarizes mitochondrial membrane potential, and induces cell death specifically in myeloid progenitors. Additionally, activation of the IFN-I/iron axis in HSCs impairs trained immunity to Mtb infection. These results identify an unanticipated immune evasion strategy of Mtb in the BM that controls the magnitude and intrinsic anti-microbial capacity of innate immunity to infection

Maternal γδ T cells shape offspring pulmonary type 2 immunity in a microbiota-dependent manner.

Immune development is profoundly influenced by vertically transferred cues. However, little is known about how maternal innate-like lymphocytes regulate offspring immunity. Here, we show that mice born from γδ T cell-deficient (TCRδ-/-) dams display an increase in first-breath-induced inflammation, with a pulmonary milieu selectively enriched in type 2 cytokines and type 2-polarized immune cells, when compared with the progeny of γδ T cell-sufficient dams. Upon helminth infection, mice born from TCRδ-/- dams sustain an increased type 2 inflammatory response. This is independent of the genotype of the pups. Instead, the offspring of TCRδ-/- dams harbors a distinct intestinal microbiota, acquired during birth and fostering, and decreased levels of intestinal short-chain fatty acids (SCFAs), such as pentanoate and hexanoate. Importantly, exogenous SCFA supplementation inhibits type 2 innate lymphoid cell function and suppresses first-breath- and infection-induced inflammation. Taken together, our findings unravel a maternal γδ T cell-microbiota-SCFA axis regulating neonatal lung immunity

Renal control of disease tolerance to malaria

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Mycobacterium tuberculosis-specific CD4+ T-cell response is increased, and Treg cells decreased, in anthelmintic-treated patients with latent TB.

In many settings, adults with active or latent tuberculosis will also be coinfected with helminths. Our study aimed to investigate how anthelmintic treatment modulates antimycobacterial immunity, in a setting where helminth reinfection should not occur. We investigated the potential impact of helminth infection on immune responses to Mycobacterium tuberculosis (Mtb) in patients with latent Mtb infection with or without helminth infection (Strongyloides or Schistosoma), and tested T-cell responses before and after anthelmintic treatment. The study was performed in migrants resident in the United Kingdom, where reexposure and reinfection following anthelmintic treatment would not occur. The frequency of CD4(+) IFN-γ(+) T cells was measured following stimulation with Mtb Purified Protein Derivative or ESAT-6/CFP-10 antigen, and concentrations of IFN-γ in culture supernatants measured by ELISA and multiplex bead array. Helminth infection was associated with a lower frequency of CD4(+) IFN-γ(+) T cells, which increased following treatment. Patients with helminth infection showed a significant increase in CD4(+) FoxP3(+) T cells (Treg) compared to those without helminth infection. There was a decrease in the frequency of Treg cells, and an associated increase in CD4(+) IFN-γ(+) T cells after the anthelmintic treatment. Here, we show a potential role of Treg cells in reducing the frequency and function of antimycobacterial CD4(+) IFN-γ(+) T cells, and that these effects are reversed after anthelmintic treatment

Regulation of the host immune system by helminth parasites

Helminth parasite infections are associated with a battery of immunomodulatory mechanisms, which impact all facets of the host immune response to ensure their persistence within the host. This broad-spectrum modulation of host immunity has intended and unintended consequences, both advantageous and disadvantageous. Thus the host may benefit from suppression of collateral damage during parasite infection, and from reduced allergic, autoimmune and inflammatory reactions. However, helminth infection can also be detrimental in reducing vaccine responses, increasing susceptibility to co-infection, and potentially reducing tumor immunosurveillance. In this review we will summarize the panoply of immunomodulatory mechanisms used by helminths, their potential utility in human disease, and prospective areas of future research

Th2/1 Hybrid Cells Occurring in Murine and Human Strongyloidiasis Share Effector Functions of Th1 Cells

Infections by the soil-transmitted threadworm Strongyloides stercoralis affect 50-100 million people worldwide, predominantly in tropic and sub-tropic regions. Here we assessed the T helper cell phenotypes in threadworm-infected patients and experimental murine infections with focus on CD4+ T cells co- expressing markers of Th2 and Th1 differentiation. We show that mice infected with the close relative S. ratti generate strong Th2 responses characterized by the expansion of CD4+ GATA-3+ cells expressing IL-4/-5/-13 in blood, spleen, gut-draining lymph nodes, lung and gut tissue. In addition to conventional Th2 cells, significantly increased frequencies of GATA-3+T-bet+ Th2/1-hybrid cells were detected in all organs and co-expressed Th2- and Th1-cytokines at intermediate levels. Assessing the phenotype of blood-derived CD4+ T cells from South Indian patients infected with S. stercoralis and local uninfected control donors we found that GATA-3 expressing Th2 cells were significantly increased in the patient cohort, coinciding with elevated eosinophil and IgE/IgG4 levels. A fraction of IL-4+CD4+ T cells simultaneously expressed IFN-γ hence displaying a Th2/1 hybrid phenotype. In accordance with murine Th2/1 cells, human Th2/1 cells expressed intermediate levels of Th2 cytokines. Contrasting their murine counterparts, human Th2/1 hybrids were marked by high levels of IFN-γ and rather low GATA-3 expression. Assessing the effector function of murine Th2/1 cells in vitro we found that Th2/1 cells were qualified for driving the classical activation of macrophages. Furthermore, Th2/1 cells shared innate, cytokine-driven effector functions with Th1 cells. Hence, the key findings of our study are that T helper cells with combined characteristics of Th2 and Th1 cells are integral to immune responses of helminth-infected mice, but also occur in helminth-infected humans and we suggest that Th2/1 cells are poised for the instruction of balanced immune responses during nematode infections

Seroprevalence of anti-SARS-CoV-2 antibodies in COVID-19 patients and healthy volunteers up to 6 months post disease onset

SARS-CoV-2 has emerged as a human pathogen, causing clinical signs, from fever to pneumonia—COVID-19—but may remain mild or asymptomatic. To understand the continuing spread of the virus, to detect those who are and were infected, and to follow the immune response longitudinally, reliable and robust assays for SARS-CoV-2 detection and immunological monitoring are needed. We quantified IgM, IgG, and IgA antibodies recognizing the SARS-CoV-2 receptor-binding domain (RBD) or the Spike (S) protein over a period of 6 months following COVID-19 onset. We report the detailed setup to monitor the humoral immune response from over 300 COVID-19 hospital patients and healthcare workers, 2500 University staff, and 198 post-COVID-19 volunteers. Anti-SARS-CoV-2 antibody responses follow a classic pattern with a rapid increase within the first three weeks after symptoms. Although titres reduce subsequently, the ability to detect anti-SARS-CoV-2 IgG antibodies remained robust with confirmed neutralization activity for up to 6 months in a large proportion of previously virus-positive screened subjects. Our work provides detailed information for the assays used, facilitating further and longitudinal analysis of protective immunity to SARS-CoV-2. Importantly, it highlights a continued level of circulating neutralising antibodies in most people with confirmed SARS-CoV-2.info:eu-repo/semantics/publishedVersio

A structurally distinct TGF-β mimic from an intestinal helminth parasite potently induces regulatory T cells.

Helminth parasites defy immune exclusion through sophisticated evasion mechanisms, including activation of host immunosuppressive regulatory T (Treg) cells. The mouse parasite Heligmosomoides polygyrus can expand the host Treg population by secreting products that activate TGF-β signalling, but the identity of the active molecule is unknown. Here we identify an H. polygyrus TGF-β mimic (Hp-TGM) that replicates the biological and functional properties of TGF-β, including binding to mammalian TGF-β receptors and inducing mouse and human Foxp3+ Treg cells. Hp-TGM has no homology with mammalian TGF-β or other members of the TGF-β family, but is a member of the complement control protein superfamily. Thus, our data indicate that through convergent evolution, the parasite has acquired a protein with cytokine-like function that is able to exploit an endogenous pathway of immunoregulation in the host