Cells In Infection Research Articles

SARS-CoV-2 infection of kidney tissues in some severe and fatal cases of COVID-19.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can lead to diverse clinical manifestations and pathologies that involve multiple organs. Even though the disease severity is manifested mainly in the respiratory tract, which is the primary target of SARS-CoV-2 infection, acute kidney injury in the form of acute tubular necrosis has also been noted in some COVID-19 cases. It is not entirely clear whether renal cells can be infected by the virus that might be involved in acute kidney disorder. In a recent publication by Radovic and colleagues (1) that has been selected as the editor's choice paper published in the Journal of Medical Virology, the authors provided strong histopathological and immunofluorescence evidence of SARS-CoV-2 infection and tissue injury of renal parenchymal and tubular epithelial cells, which strongly suggest an active viral replication in the kidney of some severe and fatal COVID-19 cases, and to a lesser extent, a potential role for innate immune cells in viral infection and renal disease pathogenesis. This article is protected by copyright. All rights reserved.

Abnormal Activation of T Cells in HIV-1 Infection After Antiretroviral Therapy

To investigate the relationship between abnormal activation of T cell subsets in peripheral whole blood and the recovery of immune function in persons infected with HIV-1, and to examine the relationship between the size of the viral reservoir of HIV-1 DNA and T cell subsets. HIV-1-infected persons who underwent routine testing between July 2019 and May 2020 were the target population of the study. According to whether, at the time of enrollment, their CD4+ T cells reached 500 cells/μL after antiretroviral therapy (ART), HIV-1-infected persons were divided into two groups, 76 in the deficiency group and 61 in the immune recovery group. In addition, 22 people who were not exposed to HIV-1, and who were tested negative for HIV-1 antibody were selected as the control group. For the three groups of subjects, tests of the T cell subsets were conducted. A total of 77 HIV-1-infected persons, with 44 from the deficiency group and 33 from the recovery group, were examined for HIV-1 DNA reservoir. The deficiency group and the recovery group were followed up 6 months later and the CD4+ T cell test results of 133 blood samples were collected, with 74 from the deficiency group and 59 from the recovery group. The proportions of activated CD4+ and CD8+ T cells of the deficiency group were higher than those of the recovery group and the control group. The proportions of senescent CD4+ and CD8+ T cells in the deficiency group were comparable to those of the recovery group, which were higher than those of the control group, showing significant differences only in senescent CD8+ T cells, and no significant difference in senescent CD4+ T cells. The deficiency group expressed higher levels of effector memory CD4+ T and CD8+ T cells than the control group did, and the recovery group only expressed a higher level of effect memory CD8+ T cells. Both the deficiency group and the recovery group showed lower levels of central memory CD4+ T and CD8+ T cells than the control group did, and the recovery group had an even lower level of central memory CD4+ T cells than the deficiency group did. The recovery group showed a higher expression level of naïve CD4+ T cells, and the deficiency group and the recovery group had lower expression levels of naïve CD8+ T cells than the control group did. There was no correlation between the size of the viral reservoir of HIV-1 DNA and CD4+ T cell count or the T cell subsets. Activated CD4+ T cells, activated CD8+ T cells, and central memory CD4+ T cells were negatively correlated with the follow-up findings for CD4+ T cells, with r at －0.378, －0.334, and －0.322, respectively ( P<0.05). Naïve CD4+ T cells and naïve CD8+ T cells were positively correlated with the follow-up findings for CD4+ T cell subset, with r at 0.350 and 0.267, respectively ( P<0.05). HIV-1 infected persons have varying degrees of abnormal immune activation of T cell subsets. The abnormal activation of some T-cell subsets is partly associated with the subsequent recovery of immune functions and the size of the viral reservoir of HIV-1 DNA was not associated with the T cell subsets.

Deleting UL49.5 in duck plague virus causes attachment, entry and spread defects

Duck plague is a disease with high morbidity and mortality rates, and it causes great losses for the duck breeding industry. Duck plague virus (DPV) is the causative agent of duck plague, and DPV UL49.5 protein (pUL49.5) is homologue of glycoprotein N (gN), which is conserved in herpesviruses. UL49.5 homologues are known to be involved in processes such as immune escape, virus assembly, viral fusion, transporter associated with antigen processing (TAP) inhibition and degradation, and maturation and incorporation of glycoprotein M. However, few studies have focused on the role of gN in the early stage of virus infection cells. In this study, we determined that DPV pUL49.5 was distributed in the cytoplasm and colocalized with the endoplasmic reticulum (ER). Moreover, we found that DPV pUL49.5 was a virion component and nonglycosylated protein. To better explore its function, BAC-DPV-ΔUL49.5 was constructed, and its attachment was only approximately 25 % of the revertant virus. Additionally, the penetration ability of BAC-DPV-ΔUL49.5 has only reached 73 % of the revertant virus. The plaque sizes produced by the UL49.5-deleted virus were approximately 58 % smaller than those produced by the revertant virus. Deleting UL49.5 mainly resulted in attachment and cell-to-cell-spread defects. Taken together, these findings suggest important roles for DPV pUL49.5 in viral attachment, penetration and spread.

The alarmin interleukin-33 promotes the expansion and preserves the stemness of Tcf-1+ CD8+ T cells in chronic viral infection

The alarmin interleukin-33 promotes the expansion and preserves the stemness of Tcf-1+ CD8+ T cells in chronic viral infection

The alarmin interleukin-33 promotes the expansion and preserves the stemness of Tcf-1+ CD8+ T cells in chronic viral infection

T cell factor 1 (Tcf-1) expressing CD8+ Tcells exhibit stem-like self-renewing capacity, rendering them key for immune defense against chronic viral infection and cancer. Yet, the signals that promote the formation and maintenance of these stem-like CD8+ Tcells (CD8+SL) remain poorly defined. Studying CD8+ Tcell differentiation in mice with chronic viral infection, we identified the alarmin interleukin-33 (IL-33) as pivotal for the expansion and stem-like functioning of CD8+SL as well as for virus control. IL-33 receptor (ST2)-deficient CD8+ Tcells exhibited biased end differentiation and premature loss of Tcf-1. ST2-deficient CD8+SL responses were restored by blockade of type I interferon signaling, suggesting that IL-33 balances IFN-I effects to control CD8+SL formation in chronic infection. IL-33 signals broadly augmented chromatin accessibility in CD8+SL and determined these cells' re-expansion potential. Our study identifies the IL-33-ST2 axis as an important CD8+SL-promoting pathway in the context of chronic viral infection.

Impact of Laboratory-Adapted Intracellular Trypanosoma cruzi Strains on the Activity Profiles of Compounds with Anti-T. cruzi Activity.

Chagas disease is caused by infection with the protozoan parasite, Trypanosoma cruzi. The disease causes ~12,000 deaths annually and is one of the world's 20 neglected tropical diseases, as defined by the World Health Organisation. The drug discovery pipeline for Chagas disease currently has few new clinical candidates, with high attrition rates an ongoing issue. To determine if the Trypanosoma cruzi strain utilised to assess in vitro compound activity impacts activity, a comparison of laboratory-adapted T. cruzi strains from differing geographical locations was undertaken for a selection of compounds with anti-T. cruzi activity. To minimise the possible effect of differences in experimental methodology, the same host cell and multiplicity of infection were utilised. To determine whether the compound exposure time influenced results, activity was determined following exposure for 48 and 72 h of incubation. To ascertain whether replication rates affected outcomes, comparative rates of replication of the T. cruzi strains were investigated, using the nucleoside analogue, 5-ethynyl-2'-deoxyuridine. Minimal differences in the in vitro activity of compounds between strains were observed following 48 h incubation, whereas significant differences were observed following 72 h incubation, in particular for the cytochrome P450 inhibitors tested and the cell cycle inhibitor, camptothecin. Thus, the use of panels of laboratory adapted strains in vitro may be dependent on the speed of action that is prioritised. For the identification of fast-acting compounds, an initial shorter duration assay using a single strain may be used. A longer incubation to identify compound activity may alternatively require profiling of compounds against multiple T. cruzi strains.

Determination of Autophagy in Human Cervicovaginal Smears by Cytological and İmmunocytochemical Methods.

Autophagy is a catabolic process whereby organelles and long-lived proteins are recycled through lysosomes to maintain cellular homeostasis. This process is being widely studied using culture techniques and animal models; however, cervicovaginal smears have not been used to detect autophagy. Our study aims to detect and evaluate autophagy in normal, malignant, infectious, and atypical cells in cervicovaginal smears by using cytological and immunocytochemical methods. Papanicolaou-stained 200 cervicovaginal smears were examined and 55 of 200 (27.5%) smears containing negative for intraepithelial lesion or malignancy (NILM) with identifiable infections and/or reactive/reparative changes (INF); briefly, NILM-INF (n = 31, 56.4%), atypical (n = 4, 7.3%), and malignant cells (n = 20, 36.3%) were evaluated as a study group. One hundred forty-five of 200 (72.5%) normal smears were accepted as the NILM without any identifiable infections (control group). The autophagy marker protein Microtubule-associated protein 1 light chain 3 A (MAP1LC3A) was used for immunocytochemical examination. The staining intensity of the MAP1LC3A protein and autophagy positivity were lower in the malignant cells; however, they were higher in the NILM-INF and atypical cells. A statistically significant correlation between the malignant and normal cells was obtained for the autophagy positivity (P = 0.012). In view of the staining intensity of MAP1LC3A protein by the H-score method, a significant correlation was found between the NILM-INF and the normal cells (P = 0.015). Autophagy was detected in various cervicovaginal smears for the first time in this study. Our findings indicate that an autophagy process is essential in infectious cells as well as in the transformation of atypical cells into malignant cells in carcinogenesis.

Accuracy of the Sysmex UF-5000 analyzer for urinary tract infection screening and pathogen classification.

The screening performance of urine flow cytometry parameters (e.g., white blood cell and bacteria) for urinary tract infection (UTI) has been widely recognized. The majority of previous studies, however, investigated the screening performance of Sysmex UF-1000i urine flow cytometer. This study aimed to investigate the screening performance of Sysmex UF-5000 analyzer, a third-generation urinary flow cytometer, for UTI and its novel parameter named Gram flag for discriminating gram-positive and negative pathogens. Urine specimens sent to the clinical microbiology laboratory of our hospital for bacterial culture between September 13, 2021, and November 15, 2021, were prospectively and consecutively collected. The Sysmex UF-5000 analyzer was used to determine urine white blood cell (WBC) and bacteria simultaneously. A chemical strip was used to assess urine nitrate. UTI was defined as positive urine bacterial culture > 104 CFU /ml. The receiver operating characteristics (ROC) curve, nomogram, decision tree, and decision curve were used to determine the screening performance of urine WBC, nitrate, and bacterial. A total of 246 UTIs and 425 non-UTIs were enrolled. The areas under the ROC curve (AUCs) for WBC and bacterial were 0.74 and 0.86, respectively. The decision curve showed that urine bacteria had a higher benefit than WBC. The nomogram indicated that urine bacterial had the largest effect on the probability of UTI. The sensitivity and specificity of the decision tree were 0.69 and 0.95, respectively. The flag of Gram-negative had a positive predictive value (PPV) of 0.93 in patients with urine bacteria > 1367 /μl. Therefore, we conclude that urine bacteria determined by the Sysmex UF-5000 had higher screening performance and greater benefit than WBC. The decision tree can be used to improve the screening performance of routine urinary parameters. The flag of Gram-negative is a reliable indicator to confirm gram-negative bacteria infection in UTI patients.

Ex vivo oncolytic and immune activity of CF33-hNIS-antiPDL1 against fresh peritoneal cells from patients with gastric cancer with and without peritoneal metastases.

430 Background: No effective therapy exists for peritoneal metastases (PM) from gastric cancer (GC), which remain fatal within months of diagnosis. We investigated a novel chimeric oncolytic virus platform, CF33-OV, for its anti-cancer potential against peritoneal cancer cells from GC patients. Methods: We prospectively collected fresh ascites or peritoneal washings from 30 GC patients between 2019 and 2020. These included 16 males (53.3%) and 14 females (46.7%) with a mean age of 51.3 ± 15.1 years. Of the 30 patients, 23 (90%) had cytology or biopsy-proven PM. Cells isolated from the peritoneal fluid were analyzed using flow cytometry for immune cell markers and/or treated with PBS, CF33-GFP (MOI=3), or CF33-hNIS-antiPDL1 (MOI=3) for 15 hours. We evaluated the treated cells for virus infection, replication, CD8+ and CD4+ expression with exhaustion markers, virus infection, replication, and cytotoxicity. We evaluated ex vivo CD274 (PD-L1) blockade by virus-encoded anti-PD-L1 scFv and the release of growth factors and cytokines following CF33-hNIS-antiPDL1 treatment. Results: The CD45- cancer cell percentage was higher, and the CD8+ T cell percentage was significantly lower in the ascites group than in the peritoneal washing group. At baseline, low levels of CD274 (PD-L1), CD252 (OX40L), and EGFR were identified on the surface of cancer cells. CD4+ and CD8+ T cells did not express cell surface exhaustion markers. After 15 hours of treatment, CF33-GFP infected, replicated in, and killed cancer cells ex vivo with a significantly higher dead cell percentage than the PBS control group (10.8% treated vs. 3.1% control, p-value &lt;0.05). Of the live cancer cells, 69% were GFP+ by flow cytometry. Fluorescence microscopy results confirmed virus-encoded GFP expression in the ex vivo cells. Moreover, CF33-hNIS-antiPDL1 produced functional anti-PD-L1 scFv, which blocked phycoerythrin labeled anti-PD-L1 binding to PD-L1 on live cancer cells. Virus treatment increased CD8+CD107α+ and CD4+CD107α+ T cell percentages while decreasing the release of growth factors (EGF and PDGF) and inhibitory immune factors (soluble anti-PD-L1, GM-CSF, and IL-10). Conclusions: CF33-hNIS-antiPDL1 is oncolytic with immune-activating effects against GCPM ex vivo and has solid potential for intraperitoneal therapy of GCPM patients.

Crosstalk between ILC2s and Th2 cells varies among mouse models.

Type 2T helper (Th2) cells and group 2 innate lymphoid cells (ILC2s) provide protection against helminth infection and are involved in allergic responses. However, their relative importance and crosstalk during type 2 immune responses are still controversial. By generating and utilizing mouse strains that are deficient in either ILC2s or Th2 cells, we report that interleukin (IL)-33-mediated ILC2 activation promotes the Th2 cell response to papain; however, the Th2 cell response to ovalbumin (OVA)/alum immunization is thymic stromal lymphopoietin (TSLP) dependent but independent of ILC2s. During helminth infection, ILC2s and Th2 cells collaborate at different phases of the immune responses. Th2 cells, mainly through IL-4 production, induce the expression of IL-25, IL-33, and TSLP, among which IL-25 and IL-33 redundantly promote ILC2 expansion. Thus, while Th2 cell differentiation can occur independently of ILC2s, activation of ILC2s may promote Th2 responses, and Th2 cells can expand ILC2s by inducing type 2 alarmins.

Gastro-Protective and Therapeutic Effect of Punica granatum against Stomach Ulcer Caused by Helicobacter Pylori.

Gastric ulcer is a chronic condition that occurs when the mucosa of the stomach is broken. There is a physiological equilibrium between aggressive factors and mucosal defense. The purpose of this research was to compare the prevention level and efficiency of herbal medicinal plants (Punica granatum) to the omeprazole drug. Many groups were prepared from Albino male rats, the first control group (inoculate withH. pyloriand fed with standard pellet), the Second group, rats inoculated byH. pyloriand prevented with Punica granatum aqueous extracts (PGAE) in two dosages (250mg/kg, 500mg/kg), and last group inoculated byH. pyloriand prevented with standard drug omeprazole at the dose (20mg/kg). The results showed that the Ulcer Inhibition % of Punica granatum with a high dose of 500mg/kg and a low dose of 250mg/kg was 84.60±5.48 and 42.87±7.14, respectively. While in the omeprazole treatment group, Ulcer Inhibition % was 24.50±6.35 and this Ulcer Inhibition % in the Punica granatum treatment groups was significant compared to the omeprazole treatment group and the control group (P=0.0001). PGAE displayed a significant lessening in stomach index and infectious cell proliferation with much cell damage. Although the result of the current study improves, a high dosage of aqueous extracts of plants has more effectiveness than a low dosage of aqueous extracts plants.

Phenotypic CD8 T cell profiling in chronic hepatitis B to predict HBV-specific CD8 T cell susceptibility to functional restoration in vitro

ObjectiveExhausted hepatitis B virus (HBV)-specific CD8 T cells in chronic HBV infection are broadly heterogeneous. Characterisation of their functional impairment may allow to distinguish patients with different capacity to control...

Functionality of immune cells in COVID-19 infection: development of cell-based therapeutics.

Introduction: In late December 2019, a sudden severe respiratory illness of unknown origin was reported in China. In early January 2020, the cause of COVID-19 infection was announced a new coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Examination of the SARS-CoV-2 genome sequence revealed a close resemblance to the previously reported SARS-CoV and coronavirus Middle East respiratory syndrome (MERS-CoV). However, initial testing of drugs used against SARS-CoV and MERS-CoV has been ineffective in controlling SARS-CoV-2. One of the key strategies to fight the virus is to look at how the immune system works against the virus, which has led to a better understanding of the disease and the development of new therapies and vaccine designs. Methods: This review discussed the innate and acquired immune system responses and how immune cells function against the virus to shed light on the human body's defense strategies. Results: Although immune responses have been revealed critical to eradicating infections caused by coronaviruses, dysregulated immune responses can lead to immune pathologies thoroughly investigated. Also, the benefit of mesenchymal stem cells, NK cells, Treg cells, specific T cells, and platelet lysates have been submitted as promising solutions to prevent the effects of infection in patients with COVID-19. Conclusion: It has been concluded that none of the above has undoubtedly been approved for the treatment or prevention of COVID-19, but clinical trials are underway better to understand the efficacy and safety of these cellular therapies.

The Role of Gut Microbiota-derived Tryptophan Metabolites in Mycobacterium tuberculosis Infection: A Mini-Review

The gut microbiota has a major contribution in human physiology and influences disease pathogenesis, including in tuberculosis (TB) lung infection. Gut-lung axis has demonstrated the interplay of these two organs, mediated by metabolites produced by the gut microbes or derived from host molecules transformation. Tryptophan (Trp) is one of the essential aromatic amino acids catabolized as kynurenine, serotonin (5-hydroxytryptamine), and indole derivatives, including indole propionic acid (IPA), via 3 pathways. The latter was microbiota-derived Trp catabolism, which has known to have an immunomodulatory role, as ligands for Aryl hydrocarbon Receptor (AhR). Intriguingly, Mycobacterium tuberculosis required Trp as a nitrogen source, especially in CD4+ T cells-generated stress, to survive in the phagosome of macrophage and to cause disease. Recently, IPA is identified as a new anti-mycobacterial compound, which is specific and has broad spectrum of anti-mycobacterial activity. The structural similarity of this gut microbiota-derived metabolite and Trp allows IPA to inhibit the TrpE anthranilate synthase in Trp biosynthesis pathway in Mtb. In this review, we summarize findings from recent work by focusing on the role of Trp metabolites in host cells in TB infection. A better understanding of this chemical signal could potentially serve as a novel strategy for managing this chronic inflammatory disease.

PIN1 and PIN4 inhibition via parvulin impeders Juglone, PiB, ATRA, 6,7,4'-THIF, KPT6566, and EGCG thwarted hepatitis B virus replication.

Human parvulin peptidyl prolyl cis/trans isomerases PIN1 and PIN4 play important roles in cell cycle progression, DNA binding, protein folding and chromatin remodeling, ribosome biogenesis, and tubulin polymerization. In this article, we found that endogenous PIN1 and PIN4 were upregulated in selected hepatocellular carcinoma (HCC) cell lines. In this study, we inhibited PIN1 and PIN4 via parvulin inhibitors (Juglone, PiB, ATRA, 6,7,4'-THIF, KPT6566, and EGCG). The native agarose gel electrophoresis (NAGE) immunoblotting analysis revealed that upon PIN1 and/ or PIN4 inhibition, the HBc protein expression and core particle or capsid synthesis reduced remarkably. The effects of PIN4 inhibition on hepatitis B virus (HBV) replication were more pronounced as compared to that of PIN1. The Northern and Southern blotting revealed reduced HBV RNA and DNA levels. During the HBV course of infection, Juglone, PiB, ATRA, 6,7,4'-THIF, KPT6566, and EGCG-mediated inhibition of PIN1 and PIN4 significantly lowered HBV transcriptional activities without affecting total levels of covalently closed circular DNA (cccDNA). Similar to the inhibitory effects of PIN1 and PIN4 on HBV replication, the knockdown of PIN1 and PIN4 in HBV infection cells revealed significantly reduced amounts of intracellular HBc, HBs, HBV pgRNA, SmRNAs, core particles, and HBV DNA synthesis. Similarly, PIN1 and PIN4 KD abrogated extracellular virion release, naked capsid levels, and HBV DNA levels. In comparison with PIN1 KD, the PIN4 KD showed reduced HBc and/or core particle stabilities, indicating that PIN4 is more critically involved in HBV replication. Chromatin immunoprecipitation (ChIP) assays revealed that in contrast to DNA binding PIN4 proteins, the PIN1 did not show binding to cccDNA. Similarly, upon PIN1 KD, the HBc recruitment to cccDNA remained unaffected. However, PIN4 KD significantly abrogated PIN4 binding to cccDNA, followed by HBc recruitment to cccDNA and restricted HBV transcriptional activities. These effects were more pronounced in PIN4 KD cells upon drug treatment in HBV-infected cells. The comparative analysis revealed that in contrast to PIN1, PIN4 is more critically involved in enhancing HBV replication. Thus, PIN1 and PIN4 inhibition or knockdown might be novel therapeutic targets to suppress HBV infection. targets to suppress HBV infection.

STAT3 regulates CD8+ T cell differentiation and functions in cancer and acute infection.

In cancer, persistent antigens drive CD8+ T cell differentiation into exhausted progenitor (Texprog) and terminally exhausted (Texterm) cells. However, how the extrinsic and intrinsic regulatory mechanisms cooperate during this process still remains not well understood. Here, we found that STAT3 signaling plays essential roles in promoting intratumor Texterm cell development by enhancing their effector functions and survival, which results in better tumor control. In tumor microenvironments, STAT3 is predominantly activated by IL-10 and IL-21, but not IL-6. Besides, STAT3 also plays critical roles in the development and function of terminally differentiated effector CD8+ T cells in acute infection. Mechanistically, STAT3 transcriptionally promotes the expression of effector function-related genes, while it suppresses those expressed by the progenitor Tex subset. Moreover, STAT3 functions in collaboration with BATF and IRF4 to mediate chromatin activation at the effector gene loci. Thus, we have elucidated the roles of STAT3 signaling in terminally differentiated CD8+ T cell development, especially in cancer, which benefits the development of more effective immunotherapies against tumors.

Inflammatory and anti-inflammatory responses in human T-lymphotropic virus Type 1 infection

Human T-lymphotropic virus Type 1 (HTLV-1) is a viral infectious agent that may cause chronic infection of T lymphocytes. HTLV-1 infection is related to multiple human diseases, including adult T-cell leukemia, which is a neoplastic growth of HTLV-1-infected T cells, and neoplastic inflammatory conditions such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), Sjögren’s syndrome, polymyositis uveitis, and bronchoalveolitis. T regulatory cells (Tregs), also known as regulatory T cells, and T helper 17 (Th17) cells, a distinct subset of cluster differentiation T cells with interleukin-17 as their major cytokine, orchestrate the pathogenesis of anti-inflammatory and inflammatory responses in HTLV-1-mediated diseases. In this review, we aim to evaluate the immune responses of Tregs as anti-inflammatory cells and Th17 cells as inflammatory cells in HTLV-1 infection.

Metabolism of NK cells during viral infections.

Cellular metabolism is essential for the correct function of immune system cells, including Natural Killer cells (NK). These cells depend on energy to carry out their effector functions, especially in the early stages of viral infection. NK cells participate in the innate immune response against viruses and tumors. Their main functions are cytotoxicity and cytokine production. Metabolic changes can impact intracellular signals, molecule production, secretion, and cell activation which is essential as the first line of immune defense. Metabolic variations in different immune cells in response to a tumor or pathogen infection have been described; however, little is known about NK cell metabolism in the context of viral infection. This review summarizes the activation-specific metabolic changes in NK cells, the immunometabolism of NK cells during early, late, and chronic antiviral responses, and the metabolic alterations in NK cells in SARS-CoV2 infection. The modulation points of these metabolic routes are also discussed to explore potential new immunotherapies against viral infections.

The ASH1–PEX16 regulatory pathway controls peroxisome biogenesis for appressorium-mediated insect infection by a fungal pathogen

Entomopathogenic fungi infect insects by penetrating through the cuticle into the host body. To breach the host cuticle, some fungal pathogens produce specialized infection cells called appressoria, which develop enormous turgor pressure to allow cuticle penetration. However, regulatory mechanisms underlying appressorium turgor generation are poorly understood. Here, we show that the histone lysine methyltransferase ASH1 in the insecticidal fungus Metarhizium robertsii, which is strongly induced during infection of the mosquito cuticle, regulates appressorium turgor generation and cuticle penetration by activating the peroxin gene Mrpex16 via H3K36 dimethylation. MrPEX16 is required for the biogenesis of peroxisomes that participate in lipid catabolism and further promotes the hydrolysis of triacylglycerols stored in lipid droplets to produce glycerol for turgor generation, facilitating appressorium-mediated insect infection. Together, the ASH1-PEX16 pathway plays a pivotal role in regulating peroxisome biogenesis to promote lipolysis for appressorium turgor generation, providing insights into the molecular mechanisms underlying fungal pathogenesis.

Aerosol delivered irradiated Escherichia coli confers serotype-independent protection and prevents colibacillosis in young chickens

Escherichia coli causes colibacillosis in chickens, which has severe economic and public health consequences. For the first time, we investigated the efficacy of gamma-irradiated E. coli to prevent colibacillosis in chickens considering different strains and application routes. Electron microscopy, alamarBlue assay and matrix assisted laser desorption/ionization time-of- flight mass spectrometry showed that the cellular structure, metabolic activity and protein profiles of irradiated and non-treated E. coli PA14/17480/5-ovary (serotype O1:K1) were similar. Subsequently, three animal trials were performed using the irradiated E. coli and clinical signs, pathological lesions and bacterial colonization in systemic organs were assessed.In the first animal trial, the irradiated E. coli PA14/17480/5-ovary administered at 7 and 21 days of age via aerosol and oculonasal routes, respectively, prevented the occurrence of lesions and systemic bacterial spread after homologous challenge, as efficient as live infection or formalin-killed cells. In the second trial, a single aerosol application of the same irradiated strain in one-day old chickens was efficacious against challenges with a homologous or a heterologous strain (undefined serotype). The aerosol application elicited better protection as compared to oculonasal route. Finally, in the third trial, efficacy against E. coli PA15/19103–3 (serotype O78:K80) was shown. Additionally, previous results of homologous protection were reconfirmed. The irradiated PA15/19103–3 strain, which also showed lower metabolic activity, was less preferred even for the homologous protection, underlining the importance of the vaccine strain. In all the trials, the irradiated E. coli did not provoke antibody response indicating the importance of innate or cell mediated immunity for protection.In conclusion, this proof-of-concept study showed that the non-adjuvanted single aerosol application of irradiated “killed but metabolically active” E. coli provided promising results to prevent colibacillosis in chickens at an early stage of life. The findings open new avenues for vaccine production with E. coli in chickens using irradiation technology.