PIM1 controls GBP1 activity to limit self-damage and to guard against pathogen infection.

Disruption of cellular activities by pathogen virulence factors can trigger innate immune responses. Interferon-γ (IFN-γ)-inducible antimicrobial factors, such as the guanylate binding proteins (GBPs), promote cell-intrinsic defense by attacking intracellular pathogens and by inducing programmed cell death. Working in human macrophages, we discovered that GBP1 expression in the absence of IFN-γ killed the cells and induced Golgi fragmentation. IFN-γ exposure improved macrophage survival through the activity of the kinase PIM1. PIM1 phosphorylated GBP1, leading to its sequestration by 14-3-3σ, which thereby prevented GBP1 membrane association. During Toxoplasma gondii infection, the virulence protein TgIST interfered with IFN-γ signaling and depleted PIM1, thereby increasing GBP1 activity. Although infected cells can restrain pathogens in a GBP1-dependent manner, this mechanism can protect uninfected bystander cells. Thus, PIM1 can provide a bait for pathogen virulence factors, guarding the integrity of IFN-γ signaling.

Tryptophan metabolism and immune alterations in pregnant Hispanic women with chronic Toxoplasma gondii infection.

PROBLEM: Pregnancy markedly modifies women's metabolism and immune functions. We hypothesized that pregnancy might alter the immune and metabolic responses to chronic Toxoplasma gondii infection in pregnancy. METHOD OF STUDY: A population of 690 pregnant Hispanic women were screened for antibodies to T. gondii and 158 women were positive (23% positivity) with 83% showing high avidity indices. These seropositive women were followed through their pregnancies with four data collection time points and a postpartum collection at two clinics in Tampa, Florida. A T. gondii seronegative group (N = 128) was randomly selected to serve as a control group and measured along pregnancy in the same way. Serum levels of tryptophan, kynurenine, and their ratio, phenylalanine, tyrosine and their ratio, neopterin, and nitrite were measured through pregnancy and the postpartum. A plasma cytokine panel (IFN-γ, TNFα, IL-2, IL-10, IL-12, IL-6, IL-17) was analyzed in parallel. RESULTS: The major findings suggest that indoleamine 2,3-dioxygenase (IDO-1) was less activated in T. gondii seropositive pregnant Hispanic women with chronic infection. Evidence for IDO-1 suppression was that tryptophan catabolism was less pronounced and there were lower levels of multiple inflammatory cytokines including IFN-γ, which is the major inducer of IDO-1, and higher nitrite concentration, a surrogate marker for nitric oxide, an inhibitor of IDO. CONCLUSIONS: Latent T. gondii infection was associated with higher plasma tryptophan levels, and lower inflammatory cytokines across pregnancy, suggesting suppression of the IDO-1 enzyme, and possible T cell exhaustion during pregnancy.

Chronic Toxoplasma gondii infection contributes to perineuronal nets impairment in the primary somatosensory cortex.

Toxoplasma gondii is able to manipulate the host immune system to establish a persistent and efficient infection, contributing to the development of brain abnormalities with behavioral repercussions. In this context, this work aimed to evaluate the effects of T. gondii infection on the systemic inflammatory response and structure of the primary somatosensory cortex (PSC). C57BL/6 and BALB/c mice were infected with T. gondii ME49 strain tissue cysts and accompanied for 30 days. After this period, levels of cytokines IFN-γ, IL-12, TNF-α and TGF-ß were measured. After blood collection, mice were perfused and the brains were submitted to immunohistochemistry for perineuronal net (PNN) evaluation and cyst quantification. The results showed that C57BL/6 mice presented higher levels of TNF-α and IL-12, while the levels of TGF-ß were similar between the two mouse lineages, associated with the elevated number of tissue cysts, with a higher occurrence of cysts in the posterior area of the PSC when compared to BALB/c mice, which presented a more homogeneous cyst distribution. Immunohistochemistry analysis revealed a greater loss of PNN labeling in C57BL/6 animals compared to BALB/c. These data raised a discussion about the ability of T. gondii to stimulate a systemic inflammatory response capable of indirectly interfering in the brain structure and function.

Tim-3 downregulation by Toxoplasma gondii infection contributes to decidual dendritic cell dysfunction.

BACKGROUND: Women in early pregnancy infected by Toxoplasma gondii may have severe adverse pregnancy outcomes, such as spontaneous abortion and fetal malformation. The inhibitory molecule T cell immunoglobulin and mucin domain 3 (Tim-3) is highly expressed on decidual dendritic cells (dDCs) and plays an important role in maintaining immune tolerance. However, whether T. gondii infection can cause dDC dysfunction by influencing the expression of Tim-3 and further participate in adverse pregnancy outcomes is still unclear. METHODS: An abnormal pregnancy model in Tim-3-deficient mice and primary human dDCs treated with Tim-3 neutralizing antibodies were used to examine the effect of Tim-3 expression on dDC dysfunction after T. gondii infection. RESULTS: Following T. gondii infection, the expression of Tim-3 on dDCs was downregulated, those of the pro-inflammatory functional molecules CD80, CD86, MHC-II, tumor necrosis factor-α (TNF-α), and interleukin-12 (IL-12) were increased, while those of the tolerant molecules indoleamine 2,3-dioxygenase (IDO) and interleukin-10 (IL-10) were significantly reduced. Tim-3 downregulation by T. gondii infection was closely associated with an increase in proinflammatory molecules and a decrease in tolerant molecules, which further resulted in dDC dysfunction. Moreover, the changes in Tim-3 induced by T. gondii infection further reduced the secretion of the cytokine IL-10 via the SRC-signal transducer and activator of transcription 3 (STAT3) pathway, which ultimately contributed to abnormal pregnancy outcomes. CONCLUSIONS: Toxoplasma gondii infection can significantly downregulate the expression of Tim-3 and cause the aberrant expression of functional molecules in dDCs. This leads to dDC dysfunction, which can ultimately contribute to abnormal pregnancy outcomes. Further, the expression of the anti-inflammatory molecule IL-10 was significantly decreased by Tim-3 downregulation, which was mediated by the SRC-STAT3 signaling pathway in dDCs after T. gondii infection.

Dynamic Immune Profile in French Toxoplasmosis Patients.

BACKGROUND: Toxoplasma gondii infection is usually benign in Europe due to the strong predominance of type II strains. Few studies have been conducted to examine the immunological course of infection in humans and have yielded conflicting results, maybe influenced by heterogeneous parasite strains. METHODS: We measured 23 immune mediators in 39, 40, and 29 sera of French noninfected, acutely infected, and chronically infected immunocompetent pregnant women, respectively. RESULTS: Four different cytokine patterns were identified regarding their dynamics through infection phases. For 11 of the cytokines (IFN-ß, IFN-γ, IL-4, IL5, IL-6, IL-10, IL-12, IL-15, CXCL9, CCL2, and CSF2) the serum levels were significantly elevated during acute infection. The inflammatory mediators IL-1ß, IL-17A, IL-18, TNF-α, and CSF3 remained unchanged during acute infection, while they were significantly lower in chronically infected compared to noninfected patients. As for the anti-inflammatory cytokines TGF-ß and CCL5, their levels remained significantly elevated during chronic infection. We also observed a significant negative correlation of several cytokine concentrations with IgG levels, indicating a rapid decline of serum concentrations during the acute phase. CONCLUSIONS: These results indicate an anti-inflammatory pattern in chronically infected patients in a type II dominated setting and demonstrate the highly dynamic immune situation during acute infection.

B7-H4 reduction induced by Toxoplasma gondii infection results in dysfunction of decidual dendritic cells by regulating the JAK2/STAT3 pathway.

BACKGROUND: Primary infection of Toxoplasma gondii can cause serious abnormal pregnancy outcomes such as miscarriage and stillbirth. Inhibitory molecule B7-H4 is abundantly expressed in dendritic cells (DCs) and plays an important role in maintaining immune tolerance. However, the role of B7-H4 in decidual DCs (dDCs) in T. gondii-induced abnormal pregnancy outcomes is not clear. METHODS: We established T. gondii-infected abnormal pregnancy model in wild-type (WT) and B7-H4 knockout (B7-H4-/-) pregnant mice in vivo and cultured primary human dDCs in vitro. The abnormal pregnancy outcomes were observed and the expression of B7-H4, functional molecules (CD80, CD86, and MHC-II or HLA-DR), indoleamine 2,3-dioxygenase (IDO), cytokines (IL-10 and IL-12), and signaling molecules JAK2/STAT3 in dDCs was detected by flow cytometry and Western blot. RESULTS: Our results showed that T. gondii infection significantly decreased B7-H4 expression in dDCs. In addition, B7-H4-/- infected pregnant mice showed much more severe abnormal pregnancy outcomes than their counterparts. Importantly, B7-H4-/- infection further regulated the expression of molecules (CD80, CD86, and MHC-II or HLA-DR), enzyme IDO, and cytokines (IL-10 and IL-12) in dDCs. We further discovered that B7-H4-/- infection impairs the JAK2/STAT3 pathway, contributing to dDC dysfunction. CONCLUSIONS: Taken together, the results show that reduction of B7-H4 by T. gondii infection significantly modulates the decrease in cytokine IL-10 and enzyme IDO and the increase in cytokine IL-12, contributing to dDC dysfunction. Moreover, the JAK2/STAT3 pathway is involved in the regulation of B7-H4 by T. gondii infection and in the subsequent IDO and cytokine production, which ultimately contributes to abnormal pregnancy outcomes.

Tylvalosin demonstrates anti-parasitic activity and protects mice from acute toxoplasmosis.

AIMS: Toxoplasmosis, caused by Toxoplasma gondii (Tg), is one of the most prevalent zoonotic diseases worldwide. Currently, safe and efficient therapeutic options for this disease are still being developed, and are urgently needed. Tylvalosin (Tyl), a broad-spectrum third-generation macrolide, exhibits anti-bacterial, anti-viral, and anti-inflammatory properties. The present study aims to explore the anti-parasitic and immunomodulation activities of Tyl against Tg, and the underlying mechanism. MAIN METHODS: Adhesion, invasion, replication, proliferation, plaque, reversibility, immunofluorescence assays and transmission electron microscopy were utilized to determine the anti-Toxoplasma effect of Tyl. With acute toxoplasmosis model and rabies virus-induced brain inflammation model, the anti-toxoplasmosis and immunomodulation activities of Tyl were assessed by colorimetric assay, histopathological and Oil red O staining, and real-time quantitative PCR. The involved molecular mechanisms were investigated by western blotting and immunohistochemical staining. KEY FINDINGS: Tyl (5 and 10 µg/ml) can inhibit Tg propagation, and damage its ultrastructure irreversibly. The combination of Tyl and Pyrimethamine (Pyr) exhibits a better synergistic effect. Tyl (50 and 100 mg/kg) treatment intraperitoneally can delay mice death and improve survival rate, accompanying the reduced histopathological score and parasite load in the indicated tissues, espically for ileum, liver, spleen, lung and brain. Furthermore, Tg can modulate host phospho-p38 MAPK (pp38), subtilisin/kexin-isozyme-1 (SKI-1)-sterol regulatory element binding protein-1 (SREBP-1) (SKI-1-SREBP-1) pathway and peroxisome proliferators-activated receptor δ (PPARδ), while Tyl is able to reverse these signal pathways close to normal levels. SIGNIFICANCE: Our findings indicate that Tyl exhibits anti-Toxoplasma activity and protects mice from acute toxoplasmosis.

Hygiene Hypothesis Indicators and Prevalence of Antinuclear Antibodies in US Adolescents.

Autoimmunity prevalence, as measured by antinuclear antibodies (ANA), is increasing in U.S. adolescents. Improved hygiene and cleaner environments in childhood may reduce exposure to infections and other immune challenges, resulting in improper immune responses to later-life exposures. We examined associations of hygiene hypothesis indicators, including asthma, allergies, and antibodies to infectious agents, with ANA prevalence, measured by HEp-2 immunofluorescence, in adolescents (aged 12-19 years) over a 25-year time span in the National Health and Nutrition Examination Survey (NHANES) (N=2,709), adjusting for age, sex, race/ethnicity, body mass index, education and survey cycle, overall and within individual time periods, using logistic regression. Prevalence of ANA in adolescents increased from 5.0% in 1988-1991 to 12.8% in 2011-2012. ANA were positively associated with diagnosis of asthma in early childhood (OR: 2.07, CI: 1.09-3.99) and the effect estimate for current hay fever was elevated but not statistically significant (OR: 1.55, CI: 0.85-2.84). Fewer than 2% of those with ANA in 1988-1991 had been diagnosed with asthma, compared with 18% in 1999-2000, and 27% in 2003-2004 and 2011-2012. ANA trended negatively with Helicobacter pylori antibodies (OR: 0.49, CI: 0.24-0.99). ANA may be useful as an additional indicator of inadequate immune education in adolescence, a critical period of growth and development.

Functional roles of cytokines in infectious disease associated colorectal carcinogenesis.

Infection processes induce various soluble factors that are carcinogens in humans; therefore, research into the soluble factors of chronic disease released from cells that have been infected with parasites is warranted. Parasitic infections in host cells release high levels of IFNγ. Studies have hypothesised that parasitosis-associated carcinogenesis might be analogous to colorectal cancers developed from inflammatory bowel diseases, whereby various cytokines and chemokines are secreted during chronic inflammation. IL-18 and IL-21 are other factors that might be involved in the development of colorectal cancer in schistosomiasis patients and patients with other infections. IL-21 has profound effects on tumour growth and immunosurveillance of colitis-associated tumourigenesis, thereby emphasising its involvement in the pathogenesis of colorectal cancer. The prominent role of IL-21 in antitumour effects greatly depends on the enhanced cytolytic activity of NK cells and the pathogenic role of IL-21, which is often associated with enhanced risks of cancer and chronic inflammatory processes. As IL-15 is also related to chronic disease, it is believed to also play a role in the antitumour effect of colorectal carcinogenesis. IL-15 generates and maintains long-term CD8+ T cell immunity against T. gondii to control the infection of intracellular pathogens. The lack of IL-15 in mice contributes to the downregulation of the IFNγ-producing CD4+ T cell response against acute T. gondii infection. IL-15 induces hyperplasia and supports the progressive growth of colon cancer via multiple functions. The limited role of IL-15 in the development of NK and CD8+ T cells suggests that there may be other cytokines compensating for the loss of the IL-15 gene.

The association of IL-3, IL-17A, and IL 27 serum levels with susceptibility to toxoplasmosis in recurrent abortion of Iraqi women.

Cytokines are a group of immunomodulatory proteins leading to a variety of immune reactions in the human; these cytokines play a significant role in the development of appropriate immune responses against T. gondii. This study aims to reveal the association of toxoplasmosis with serum levels of IL-3, IL-17A, and IL-27 in aborted women. The blood samples of patients and controls were collected from Al-Alawiya Maternity Teaching Hospital/Baghdad/Iraq from 2019 to 2020 for detecting anti-T. gondii antibodies (IgG and IgM) and the level of interleukins by ELISA. The results of TORCH by rapid test for recurrent abortion recorded 25.3% seropositive for anti-Toxoplasma antibodies, and 31.5% seropositive for one or more cases of TORCH test (Cytomegalovirus, Rubella, and Herpes). Whereas the results for anti-T. gondii IgG and IgM antibodies were shown elevated positivity percentages by ELISA test; these percentages were 56.2% in recurrent abortion women with significant differences (P < 0.05). The results suggested that the IL-3 serum concentration of pregnant women, recurrent abortion, and recurrent abortion with toxoplasmosis was declined versus healthy women with significant differences (p < 0.05). However, the results revealed that the concentration of IL-17A in recurrent abortion, and recurrent abortion with toxoplasmosis elevated versus healthy women and pregnant women with significant difference (p < 0.05). Whereas the results indicated that the IL-27 serum concentration elevated with significant differences in recurrent abortion with toxoplasmosis group compared to healthy women, pregnant women, and recurrent abortion. Interestingly, the serum levels for IL-27 increased comparing to the levels of IL-3 and IL-17A in all groups with significant differences (P < 0.05). In conclusion, it appeared in this study that the role of IL-3, IL-17A, and IL-27 in the maternal immune response during infections can lead to abortion.

Expression of Interleukin-33 Gene in Hemodialysis Patients with Chronic Toxoplasmosis in Baghdad, Iraq.

Toxoplasmosis is a protozoan parasite with high distribution, leading to different abnormalities in hosts. The present study aimed to determine the distribution of toxoplasmosis in hemodialysis patients and the expression of the Interleukin (IL)-33 gene in chronic Toxoplasmosis. The present study evaluated 120 subjects, including 60 patients who were undergoing dialysis and 60 healthy samples as the control group, from the 1st February to 1st November 2021. Anti-Toxoplasma gondii IgG was detected by using the enzyme-linked immunosorbent assay (ELISA) technique and the real-time polymerase-chain-reaction (PCR) was used to perform IL-33. The results demonstrated that the highest anti-toxoplasmosis IgG antibody rate was observed in the age group 51-70 years who were undergoing dialysis, in comparison with that in the control group (P<0.05). The male patients who had anti-toxoplasmosis IgG antibodies outnumbered the healthy people (P<0.05), while the female patients did not significantly differ from the healthy group. Chronic toxoplasmosis showed a higher number according to residency (the urban and rural patients), compared to healthy people. The frequency of dialysis times per week in chronic Toxoplasmosis patients was significantly higher among the infected patients. The findings were displayed to be positive in dialysis at 2 weeks (P<0.05). The expression of the IL-33 gene was investigated in patients who were undergoing hemodialysis and in healthy controls by using real-time PCR. The findings demonstrated that there was a high Ct value for patients and controls with a high Ct value of templates, preoperational to the gene concentration. The high prevalence of toxoplasmosis in dialysis patients and the role of IL-33 in cellular immunity in these patients highlight the need to investigate the mechanisms limiting infection with intracellular protozoa.

Toxoplasma-proximal and distal control by GBPs in human macrophages.

Human guanylate binding proteins (GBPs) are key players of interferon-gamma (IFNγ)-induced cell intrinsic defense mechanisms targeting intracellular pathogens. In this study, we combine the well-established Toxoplasmagondii infection model with three in vitro macrophage culture systems to delineate the contribution of individual GBP family members to control this apicomplexan parasite. Use of high-throughput imaging assays and genome engineering allowed us to define a role for GBP1, 2 and 5 in parasite infection control. While GBP1 performs a pathogen-proximal, parasiticidal and growth-restricting function through accumulation at the parasitophorous vacuole of intracellular Toxoplasma, GBP2 and GBP5 perform a pathogen-distal, growth-restricting role. We further find that mutants of the GTPase or isoprenylation site of GBP1/2/5 affect their normal function in Toxoplasma control by leading to mis-localization of the proteins.

Tbet Expression by Regulatory T Cells Is Needed to Protect against Th1-Mediated Immunopathology during Toxoplasma Infection in Mice.

Toxoplasma gondii infection has proven to be an ideal model to understand the delicate balance between protective immunity and immune-mediated pathology during infection. Lethal infection causes a collapse of T regulatory cells (Tregs) mediated by the loss of IL-2 and conversion of Tregs to IFN-γ-producing cells. Importantly, these Tregs highly express the Th1 transcription factor Tbet. To determine the role of Tbet in Tregs, we infected Tbx21f/f -Foxp3YFPCre and control Foxp3YFPCre mice with the type II strain of T. gondii, ME49. The majority of Tbx21f/f -Foxp3YFPCre mice succumbed to a nonlethal dose. Notably, parasite burden was reduced in Tbx21f/f -Foxp3YFPCre compared with Foxp3YFPCre control mice. We found that Tbx21f/f -Foxp3YFPCre mice have significantly higher serum levels of proinflammatory cytokines IFN-γ and TNF-α, suggestive of a heightened immune response. To test if CD4+ T cells were driving immunopathology, we treated Tbx21f/f -Foxp3YFPCre mice with anti-CD4-depleting Abs and partially rescued these mice. Broad-spectrum antibiotic treatment also improved survival, demonstrating a role for commensal flora in immunopathology in Tbx21f/f -Foxp3YFPCre mice. RNA sequencing analysis reinforced that Tbet regulates several key cellular pathways, including leukocyte activation, regulation of lymphocyte activation, and cell cycle progression, that help to maintain fitness in Tregs during Th1 responses. Taken together, our data show an important role for Tbet in Tregs in preventing lethal immunopathology during T. gondii infection, further highlighting the protective role of Treg plasticity in controlling immune responses to infection and the microbiota.

MicroRNA-155 contributes to host immunity against Toxoplasma gondii.

Toxoplasma gondii is well known to infect almost all avian and mammalian species including humans, with worldwide distribution. This protozoan parasite can cause serious toxoplasmosis, posing with a risk to public health. The role of microRNAs in the pathogenesis of T. gondii has not been well described. The aim of the present study was to investigate the role of microRNA-155 (miR-155) in mediating innate and adaptive immune responses during T. gondii infection in mice models. The survival and parasite burden in T. gondii-infected miR-155-/- and wild-type (WT) C57BL6 mice were compared. In these two mouse models, ELISA tests were used for analysis of Th1-associated, Th2-associated, and Th17-associated cytokines, and flow cytometry was used for analysis of the subpopulations of NK, NKT, CD8+T, CD4+T cells and regulatory T cells (Tregs), as well as Ly6Chi inflammatory monocytes and dendritic cells. The lack of miR-155 led to increased parasite burden and decreased survival of infected mice in contrast to WT mice. Innate and adaptive immune responses were reduced in the absence of miR-155, along with decreased proinflammatory mediators, Th-1-associated and Th-2-associated cytokines and accumulation of lymphocyte subpopulations. Also, CD8+ T cell exhaustion was also worsened in the absence of miR-155 via targeting of SHIP-1 and SOCS1, showing as up-regulated recruitment of Tregs and expression of PD-1, and down-regulated expression of IFN-γ and TNF-α in CD8+ T cells. Our results show that miR-155 is a critical immune regulator for the control of T. gondii infection, suggesting that miR-155 can be explored as a potential molecular target for boosting immunity against T. gondii.

TITLE: Le microARN-155 contribue à l'immunité de l'hôte contre Toxoplasma gondii. ABSTRACT: Toxoplasma gondii est bien connu pour infecter presque toutes les espèces aviaires et mammifères, y compris les humains, avec une distribution mondiale. Ce parasite protozoaire peut provoquer une toxoplasmose grave, présentant un risque pour la santé publique. Le rôle des microARN dans la pathogenèse de T. gondii n'a pas été bien décrit. Le but de la présente étude était d'étudier le rôle du microARN-155 (miR-155) dans la médiation des réponses immunitaires innées et adaptatives lors d'une infection à T. gondii dans des modèles de souris. La survie et la charge parasitaire chez les souris miR-155−/− et de type sauvage C57BL6 infectées par T. gondii ont été comparées. Dans ces deux modèles de souris, des tests ELISA ont été utilisés pour l'analyse des cytokines associées à Th1, Th2 et Th17, et la cytométrie en flux a été utilisée pour l'analyse des sous-populations de cellules NK, NKT, CD8+T, CD4+T et les cellules T régulatrices (Tregs), ainsi que les monocytes inflammatoires Ly6Chi et les cellules dendritiques. L'absence de miR-155 a entraîné une augmentation de la charge parasitaire et une diminution de la survie des souris infectées contrairement aux souris de type sauvage. Les réponses immunitaires innées et adaptatives ont été réduites en l'absence de miR-155, ainsi qu'une diminution des médiateurs pro-inflammatoires, des cytokines associées à Th-1 et Th-2 et à une accumulation de sous-populations de lymphocytes. En outre, l'épuisement des lymphocytes T CD8+ s'est également aggravé en l'absence de miR-155 via le ciblage de SHIP-1 et SOCS1, se manifestant par un recrutement régulé à la hausse des Tregs et l'expression de PD-1, et une expression régulée à la baisse de l'IFN-γ et TNF-α dans les cellules T CD8+. Nos résultats montrent que miR-155 est un régulateur immunitaire essentiel pour le contrôle de l'infection à T. gondii, suggérant que miR-155 peut être exploré comme cible moléculaire potentielle pour renforcer l'immunité contre T. gondii.

Genetic Analyses of Common Infections in the Avon Longitudinal Study of Parents and Children Cohort.

The burden of infections on an individual and public health is profound. Many observational studies have shown a link between infections and the pathogenesis of disease; however a greater understanding of the role of host genetics is essential. Children from the longitudinal birth cohort, the Avon Longitudinal Study of Parents and Children, had 14 antibodies measured in plasma at age 7: Alpha-casein protein, beta-casein protein, cytomegalovirus, Epstein-Barr virus, feline herpes virus, Helicobacter pylori, herpes simplex virus 1, influenza virus subtype H1N1, influenza virus subtype H3N2, measles virus, Saccharomyces cerevisiae, Theiler's virus, Toxoplasma gondii, and SAG1 protein domain, a surface antigen of Toxoplasma gondii measured for greater precision. We performed genome-wide association analyses of antibody levels against these 14 infections (N = 357 - 5010) and identified three genome-wide signals (P < 5×10-8), two associated with measles virus antibodies and one with Toxoplasma gondii antibodies. In an association analysis focused on the human leukocyte antigen (HLA) region of the genome, we further detected 15 HLA alleles at a two-digit resolution and 23 HLA alleles at a four-digit resolution associated with five antibodies, with eight HLA alleles associated with Epstein-Barr virus antibodies showing strong evidence of replication in UK Biobank. We discuss how our findings from antibody levels complement other studies using self-reported phenotypes in understanding the architecture of host genetics related to infections.

Seroprevalence of Toxoplasma gondii, Rubella, Group A Streptococcus, CMV and HSV-1 in COVID-19 Patients with Vitamin D Deficiency.

<b>Background and Objective:</b> In recent years, respiratory tract viral infections have caused many pandemics that impact the whole world. To investigate the seropositivity of <i>Toxoplasma gondii</i>, rubella, CMV, HSV-1 and group A <i>Streptococcus</i> in recovered COVID-19 patients and correlate these findings with vitamin D levels. <b>Materials and Methods:</b> A total of 417 COVID-19 patients with diarrhoea were enrolled in this study. Vitamin D and seroprevalence for <i>Toxoplasma gondii</i>, rubella, CMV, HSV-1 and group A <i>Streptococcus</i> were evaluated and correlated. <b>Results:</b> It was found that recent infection in COVID-19 patients with HSV-1, rubella, <i>Toxoplasma</i> and CMV, respectively. IgG was detected indicating the development of adaptive immunity with all microbes. <b>Conclusion:</b> Current study detected a correlation between vitamin D levels and HSV-1 and no correlation between this infection and vitamin D deficiency with the other microbes.

Toxoplasma gondii Tyrosine-Rich Oocyst Wall Protein: A Closer Look through an In Silico Prism.

Toxoplasmosis is a global threat with significant zoonotic concern. The present in silico study was aimed at determination of bioinformatics features and immunogenic epitopes of a tyrosine-rich oocyst wall protein (TrOWP) of Toxoplasma gondii. After retrieving the amino acid sequence from UniProt database, several parameters were predicted including antigenicity, allergenicity, solubility and physico-chemical features, signal peptide, transmembrane domain, and posttranslational modifications. Following secondary and tertiary structure prediction, the 3D model was refined, and immunogenic epitopes were forecasted. It was a 25.57 kDa hydrophilic molecule with 236 residues, a signal peptide, and significant antigenicity scores. Moreover, several linear and conformational B-cell epitopes were present. Also, potential mouse and human cytotoxic T-lymphocyte (CTL) and helper T-lymphocyte (HTL) epitopes were predicted in the sequence. The findings of the present in silico study are promising as they render beneficial characteristics of TrOWP to be included in future vaccination experiments.

Resveratrol modulates Toxoplasma gondii infection induced liver injury by intervening in the HMGB1/TLR4/NF-κB signaling pathway.

Toxoplasma gondii (T. gondii) is an obligate intracellular parasite that can cause liver diseases in the host, including hepatitis and hepatomegaly. High mobility group box 1 (HMGB1) is the main inflammatory mediator causing cell injury or necrosis. HMGB1 binds to toll like receptor 4 (TLR4), then activates the nuclear factor-κB (NF-κB) signaling pathway, which promotes the release of inflammatory factors. Our previous studies showed that HMGB1 mediated TLR4/NF-κB signaling pathway plays an important role in liver injury induced by T. gondii infection. Resveratrol (RSV) is a small polyphenol, which has anti-inflammatory, anti-cancer, anti-T. gondii effect. However, the effect of RSV on liver injury caused by T. gondii infection is unclear. This study used the RH strain tachyzoites of T. gondii to infect murine liver line, NCTC-1469 cells to establish an in vitro model and acute infection of mice for the in vivo model to explore the protective effect of RSV on liver injury induced by T. gondii infection. The results showed that RSV inhibited the proliferation of T. gondii in the liver, reduced the alanine aminotransferase/aspartate aminotransferase levels and pathological liver damage. Additionally, RSV inhibited the production of tumor necrosis factor-α, inducible nitric oxide synthase and HMGB1 by interfering with the TLR4/NF-κB signaling pathway. These results indicate that RSV can protect liver injury caused by T. gondii infection by intervening in the HMGB1/TLR4/NF-κB signaling pathway. This study will provide a theoretical basis for RSV treatment of T. gondii infection induced liver injury.

Yeast Shells Encapsulating Adjuvant AS04 as an Antigen Delivery System for a Novel Vaccine against Toxoplasma Gondii.

Toxoplasma gondii (T. gondii) infection causes severe zoonotic toxoplasmosis, which threatens the safety of almost one-third of the human population globally. However, there is no effective protective vaccine against human toxoplasmosis. This necessitates anti-T. gondii vaccine development, which is a main priority of public health. In this study, we optimized the adjuvant system 04 (AS04), a vaccine adjuvant constituted by 3-O-desacyl-4'-monophosphoryl lipid A (a TLR4 agonist) and aluminum salts, by packing it within natural extracts of ß-glucan particles (GPs) from Saccharomyces cerevisiae to form a GP-AS04 hybrid adjuvant system. Through a simple mixing procedure, we loaded GP-AS04 particles with the total extract (TE) of T. gondii lysate, forming a novel anti-T. gondii vaccine GP-AS04-TE. Results indicated that the hybrid adjuvant can efficiently and stably load antigens, mediate antigen delivery, facilitate the dendritic uptake of antigens, boost dendritic cell maturation and stimulation, and increase the secretion of pro-inflammatory cytokines. In the mouse inoculation model, GP-AS04-TE significantly stimulated the function of dendritic cells, induced a very strong TE-specific humoral and cellular immune response, and finally showed a strong and effective protection against toxoplasma chronic and acute infections. This work proves the potential of GP-AS04 for exploitation as a vaccine against a range of pathogens.

Murine Irgm Paralogs Regulate Nonredundant Functions To Execute Host Defense to Toxoplasma gondii.

Gamma interferon (IFN-γ)-induced immunity-related GTPases (IRGs) confer cell-autonomous immunity to the intracellular protozoan pathogen Toxoplasma gondii. Effector IRGs are loaded onto the Toxoplasma-containing parasitophorous vacuole (PV), where they recruit ubiquitin ligases, ubiquitin-binding proteins, and IFN-γ-inducible guanylate-binding proteins (Gbps), prompting PV lysis and parasite destruction. Host cells lacking the regulatory IRGs Irgm1 and Irgm3 fail to load effector IRGs, ubiquitin, and Gbps onto the PV and are consequently defective for cell-autonomous immunity to Toxoplasma. However, the role of the third regulatory IRG, Irgm2, in cell-autonomous immunity to Toxoplasma has remained unexplored. Here, we report that Irgm2 unexpectedly plays a limited role in the targeting of effector IRGs, ubiquitin, and Gbps to the Toxoplasma PV. Instead, Irgm2 is instrumental in the decoration of PVs with γ-aminobutyric acid receptor-associated protein-like 2 (GabarapL2). Cells lacking Irgm2 are as defective for cell-autonomous host defense to Toxoplasma as pan-Irgm-/- cells lacking all three Irgm proteins, and Irgm2-/- mice succumb to Toxoplasma infections as readily as pan-Irgm-/- mice. These findings demonstrate that, relative to Irgm1 and Irgm3, Irgm2 plays a distinct but critically important role in host resistance to Toxoplasma.