Host-derived CEACAM-laden vesicles engage enterotoxigenic Escherichia coli for elimination and toxin neutralization.

Enterotoxigenic Escherichia coli (ETEC) cause hundreds of millions of diarrheal illnesses annually ranging from mildly symptomatic cases to severe, life-threatening cholera-like diarrhea. Although ETEC are associated with long-term sequelae including malnutrition, the acute diarrheal illness is largely self-limited. Recent studies indicate that in addition to causing diarrhea, the ETEC heat-labile toxin (LT) modulates the expression of many genes in intestinal epithelia, including carcinoembryonic cell adhesion molecules (CEACAMs) which ETEC exploit as receptors, enabling toxin delivery. Here, however, we demonstrate that LT also enhances the expression of CEACAMs on extracellular vesicles (EV) shed by intestinal epithelia and that CEACAM-laden EV increase in abundance during human infections, mitigate pathogen-host interactions, scavenge free ETEC toxins, and accelerate ETEC clearance from the gastrointestinal tract. Collectively, these findings indicate that CEACAMs play a multifaceted role in ETEC pathogen-host interactions, transiently favoring the pathogen, but ultimately contributing to innate responses that extinguish these common infections.

Repeat modules and N-linked glycans define structure and antigenicity of a critical enterotoxigenic E. coli adhesin.

Enterotoxigenic Escherichia coli (ETEC) cause hundreds of millions of cases of infectious diarrhea annually, predominantly in children from low-middle income regions. Notably, in children, as well as volunteers challenged with ETEC, diarrheal severity is significantly increased in blood group A (bgA) individuals. EtpA, is a secreted glycoprotein adhesin that functions as a blood group A lectin to promote critical interactions between ETEC and blood group A glycans on intestinal epithelia for effective bacterial adhesion and toxin delivery. EtpA is highly immunogenic resulting in robust antibody responses following natural infection and experimental challenge of volunteers with ETEC. To understand how EtpA directs ETEC-blood group A interactions and stimulates adaptive immunity, we mutated EtpA, mapped its glycosylation by mass-spectrometry (MS), isolated polyclonal (pAbs) and monoclonal antibodies (mAbs) from vaccinated mice and ETEC-infected volunteers, and determined structures of antibody-EtpA complexes by cryo-electron microscopy. Both bgA and mAbs that inhibited EtpA-bgA interactions and ETEC adhesion, bound to the C-terminal repeat domain highlighting this region as crucial for ETEC pathogen-host interaction. MS analysis uncovered extensive and heterogeneous N-linked glycosylation of EtpA and cryo-EM structures revealed that mAbs directly engage these unique glycan containing epitopes. Finally, electron microscopy-based polyclonal epitope mapping revealed antibodies targeting numerous distinct epitopes on N and C-terminal domains, suggesting that EtpA vaccination generates responses against neutralizing and decoy regions of the molecule. Collectively, we anticipate that these data will inform our general understanding of pathogen-host glycan interactions and adaptive immunity relevant to rational vaccine subunit design.

Host-derived CEACAM-laden vesicles engage enterotoxigenic E. coli for elimination and toxin neutralization.

Enterotoxigenic Escherichia coli (ETEC) cause hundreds of millions of diarrheal illnesses annually ranging from mildly symptomatic cases to severe, life-threatening cholera-like diarrhea. Although ETEC are associated with long-term sequelae including malnutrition, the acute diarrheal illness is largely self-limited. Recent studies indicate that in addition to causing diarrhea, the ETEC heat-labile toxin (LT) modulates the expression of many genes in intestinal epithelia, including carcinoembryonic cell adhesion molecules (CEACAMs) which ETEC exploit as receptors, enabling toxin delivery. Here however, we demonstrate that LT also enhances the expression of CEACAMs on extracellular vesicles (EV) shed by intestinal epithelia and that CEACAM-laden EV increase in abundance during human infections, mitigate pathogen-host interactions, scavenge free ETEC toxins, and accelerate ETEC clearance from the gastrointestinal tract. Collectively, these findings indicate that CEACAMs play a multifaceted role in ETEC pathogen-host interactions, transiently favoring the pathogen, but ultimately contributing to innate responses that extinguish these common infections.

Intrinsic Causes of Nonfibrotic Portal Hypertension-A Clinicopathologic Review of 56 Patients.

Aim: The differential diagnosis of intrinsic nonfibrotic conditions that may lead to portal hypertension include hepatoportal sclerosis (HPS), nodular regenerative hyperplasia (NRH), and sinusoidal obstruction syndrome (SOS). In this article, we characterize the clinical features and outcome of these lesions when they manifest as portal hypertension. Methods: Data was collected through retrospective patient medical records. Results: Patients (HPS: 28, NRH: 17, SOS: 11) were identified more frequently in recent years. All groups presented with signs and symptoms of portal hypertension. All patients had complex medical histories. An elevated serum alkaline phosphatase occurred in all groups and an elevated bilirubin with SOS. Imaging of the liver with HPS and NRH suggested cirrhosis, which was not seen with SOS. 11%, 12%, and 9% of patients in the HPS, NRH, and SOS respectively, underwent transjugular intrahepatic portosystemic shunt placement to manage the complications of portal hypertension, while 43%, 24%, and 36% of patients respectively, received a liver transplant. Conclusions: Patients with HPS, NRH, and SOS had complex medical histories, likely contributing to the development of these lesions. They are recognized more frequently now. In contrast to HPS and NRH, SOS occurred in liver transplant recipients, was associated with elevated serum bilirubin, and imaging did not suggest the presence of advanced fibrosis/cirrhosis. Liver transplantation appeared to be a viable treatment for complications related to HPS and NRH. Retransplantation for SOS yielded mixed results. HPS, SOS, and NRH should be considered when evaluating liver specimens from patients with unexplained nonfibrotic portal hypertension. Key message: Intrinsic nonfibrotic causes of portal hypertension appear to be increasing in frequency. The differential diagnosis includes NRH, HPS, and SOS. These conditions are associated with complex diseases and possibly due to treatments. Pathologists need to be aware of this differential diagnosis when presented with liver biopsies performed to assess portal hypertension.

Hepatoportal Sclerosis-A Clinicopathologic Review of 28 Cases.

Background and Aims: The aim of this study was to review a large series of cases with hepatoportal sclerosis (HPS) as a pathologically recognizable entity in liver tissue specimens and describe the associated clinical and radiographic manifestations, along with the outcomes of this entity. Methods: Data were collected through a retrospective chart review. Results: Twenty-eight patients were identified that had pathologically defined HPS. All patients had a significant past medical history and signs and symptoms of portal hypertension. The most consistent laboratory finding was an elevated alkaline phosphatase. Radiographically, 9 patients were mistakenly identified as having advanced fibrosis/cirrhosis. The initial histologic diagnosis was made on biopsy in 20 patients and after transplant in 8 patients. The severity of symptoms was variable and required transplantation in 11 patients, 3 were treated with transjugular intrahepatic portosystemic shunt, and the remaining patients were treated symptomatically. Conclusion: HPS is associated with past medical history that may be causal in nature. Signs and symptoms may be severe enough to require liver transplantation. A significant proportion of patients are radiographically misdiagnosed as cirrhosis. In this small series, overall outcomes for transplanted patients are acceptable.

Stem cell induced inflammatory hypertrophy of the cauda equina.

Stem cell therapy can present clinicians with challenging clinical scenarios, as access to such treatments outpaces the research into their efficacy and safety due to the burgeoning trend of international travel to acquire stem cell therapy, or "stem cell tourism." Treatment of neurologic conditions remains an enticing potential application of stem cell therapy, often administered intrathecally. In response to such therapy, multiple adverse events have been described in the literature, including neoplasms, demyelinating disease, and seizures, among others. We present a case of symptomatic inflammatory cauda equina nerve root hypertrophy due to intrathecal stem cell infusion, representing a rare but significant complication.

Challenges in Treating Statin-Associated Necrotizing Myopathy.

Myalgia and mild elevation in muscle enzymes are common side effects of statin therapy. While these symptoms are generally self-limited, in rare cases, statin use is associated with an immune-mediated necrotizing myopathy caused by development of autoantibodies against HMG-CoA reductase. The primary presenting symptom of this condition is progressive symmetric proximal weakness that does not abate or worsens even after cessation of statin therapy and is associated with markedly elevated creatine kinase (CK) levels. To date, no randomized controlled trials have been conducted to identify the most effective treatment for statin-associated autoimmune myopathy. Treatment recommendations involve a combination of steroids and immunosuppressive drugs. This single-center case series highlights the clinicopathologic features diagnostic for statin-associated autoimmune myopathy as well as treatment challenges for the patient population. The series highlights a range of potential presentations, from mildly symptomatic despite highly elevated CK, to severe muscle weakness including dysphagia. Multiple patients required several immunosuppressant medications as well as intravenous immunoglobulin (IVIG) to achieve disease control. In this case series, marked improvement was noted in several diabetic patients with IVIG.

Disseminated Herpes Simplex Virus in an Immunocompetent Patient Without Presence of Epidermal or Mucosal Lesions.

ABSTRACT: Herpes simplex virus (HSV) is a disease usually characterized by lesions within the epidermis or mucosa of children and adults. However, this infection can also cause complications to many systems of the body, including the peripheral and central nervous system, respiratory system, and hepatobiliary system. In this case, we present a 43-year-old man with a history of substance abuse, who presented with fever, cough, and headache, and within days, progressed into fulminant hepatitis and hypoxic failure. Bacterial and fungal cultures were negative, as well as the workup for human immunodeficiency virus. However, the presence of HSV was detected in a bronchial lavage culture after the patients had expired. This result, along with the findings at autopsy, including viral cytopathic effect in the lung and liver, which were confirmed with immunohistochemical stains for HSV, strongly suggest that the cause of death is from disseminated herpes virus infection with hepatitis and viral pneumonitis. This disseminated infection occurred in an immunocompetent host without any evidence of mucocutaneous lesions.

Enzymatic decolorization of melanin by lignin peroxidase from Phanerochaete chrysosporium.

Skin darkening results as a consequence of the accumulation of skin pigment melanin. To combat this, the amplitude of skin lightening agents are commercially available, most of which inhibit melanin synthesis. Decolorization of melanin is an alternative method of skin lightening. In this study, we show that lignin peroxidase (LiP), an extracellular enzyme purified from Phanerochaete chrysosporium NK-1 isolated from a forest soil can effectively degrade and decolorize melanin in vitro. Decolorization conditions including pH, temperature, incubation time, enzyme concentration, and mediator addition were investigated to optimize the reaction conditions. The results indicate that pH 3, 40 °C, 15 IU/ml, and 10 h incubation were the optimal conditions for the decolorization of the melanin. The use of the mediator, veratryl alcohol was also found effective to enhance the efficacy of the melanin decolonization, with up to 92% decolorization. The scanning electron microscopy results showed void spaces on the treated melanin granules as compared to the untreated sample, indicating the degradation of melanin. Changes in the fingerprint region of the melanin were observed. Between wavenumbers 1500-500 cm-1, for example, the presence of new peaks in the treated melanin at 1513, 1464, and 1139 cm-1 CH2, CH3 bend and C-O-C stretch represented structural changes. A new peak at 2144 cm-1 (alkynyl C≡C stretch) was also detected in the decolorized melanin. The cytotoxicity study has shown that the treated melanin and LiP have low cytotoxic effects; however, the mediator of veratryl alcohol could result in high mortality which suggests that its use should be meticulously tested in formulating health and skincare products. The findings of the study suggest that LiP produced by Phanerochaete chrysosporium has the potential to be used in the medical and cosmetic industries, particularly for the development of biobased cosmetic whitening agents.

Structural vaccinology approach to investigate the virulent and secretory proteins of Bacillus anthracis for devising anthrax next-generation vaccine.

Communicated by Ramaswamy H. Sarma.

Lignin peroxidase isoenzyme: a novel approach to biodegrade the toxic synthetic polymer waste.

Fungal metabolites are playing an immense role in developing various sustainable waste treatment processes. The present study aimed at production and characterization of fungal lignin peroxidase (EC 1.11.1.14) with a potential to degrade Polyvinyl Chloride. Optimization studies revealed that the maximum enzyme production occurred at a temperature 25°C, pH 5 in the 4th week of the incubation period with fungal strain. Enzyme assay was performed to find out the dominating enzyme in the culture broth. The molecular weight of the enzyme was found to be 46 kDa. Partially purified lignin peroxidase from Phanerocheate chrysosporium was used for the degradation of PVC films. A significant reduction in the weight of PVC film was observed (31%) in shake flask experiment. FTIR spectra of the enzyme-treated plastic film revealed structural changes in the chemical composition, indicating a specific peak at 2943 cm-1 that corresponded to alkenyl C-H stretch. Moreover, deterioration on the surface of PVC films was confirmed by Scanning Electron Microscopy tracked through activity assay for the lignin peroxidase. Extracellular lignin peroxidases from P. chrysosporium play a significant role in the degradation of complex polymeric compounds like PVC.

Exploratory algorithm to devise multi-epitope subunit vaccine by investigating Leishmania donovani membrane proteins.

Visceral leishmaniasis (VL) is a deadly parasitic infection which affects poorest to poor population living in the endemic countries. Increasing resistant to existing drugs, disease burden and a significant number of deaths, necessitates the need for an effective vaccine to prevent the VL infection. This study employed a combinatorial approach to develop a multi-epitope subunit vaccine by exploiting Leishmania donovani membrane proteins. Cytotoxic T- and helper T-lymphocyte binding epitopes along with suitable adjuvant and linkers were joined together in a sequential manner to design the subunit vaccine. The occurrence of B-cell and IFN-γ inducing epitopes approves the ability of subunit vaccine to develop humoral and cell-mediated immune response. Physiochemical parameters of vaccine protein were also assessed followed by homology modeling, model refinement and validation. Moreover, disulfide engineering was performed for the increasing stability of the designed vaccine and molecular dynamics simulation was performed for the comparative stability purposes and to conform the geometric conformations. Further, molecular docking and molecular dynamics simulation study of a mutated and non-mutated subunit vaccine against TLR-4 immune receptor were performed and respective complex stability was determined. In silico cloning ensures the expression of designed vaccine in pET28a(+) expression vector. This study offers a cost-effective and time-saving way to design a novel immunogenic vaccine that could be used to prevent VL infection. Communicated by Ramaswamy H. Sarma.

Examination of antigenic proteins of Trypanosoma cruzi to fabricate an epitope-based subunit vaccine by exploiting epitope mapping mechanism.

Chagas disease is a protozoan parasitic disease caused by Trypanosoma cruzi. This injurious disease spread by the circulation of the blood sucking triatomine insects and transmitted to humans. Chagas disease is endemic in Latin America and also known as American trypanosomasis. Currently, 7 million people are infected by T. cruzi infection and about 22,000 death cases were reported per year throughout the Americas. Various immunization approaches against T. cruzi infection have been examined and some of the developed vaccine showed efficacy in animal models but there is no effective and safe vaccines for humans have been developed yet. Since, the drug resistance is increasing day by day because the developed drug (nifurtimox and benznidazole) to control T. cruzi infection, failed to activate a prodrug and still no drug and vaccine have been established. To control the infection of chagas disease, here in this study we use immunoinformatics method to design multi-epitope subunit vaccine against T. cruzi infection. Moreover, on the basis of immunogenicity B and T cell epitopes were evaluated. The allergenicity, antigenicity was predicted to ensure the safety of vaccine constructs whereas, the physiochemical property showing the stable nature of final vaccine model. Further, molecular docking was performed to optimize the interaction between TLR-2 and TLR-4 (receptor) and vaccine model (ligand) complex. Molecular dynamics simulation was performed to evaluate the energy minimization; RMSD and RMSF plot which confirm the stability of TLR-2 and TLR-4 (receptor) present on immune cells and vaccine model (ligand) complex. This study needed the experimental validation for the safety and immunogenic behavior of designed vaccine protein and it may be helpful in future to control T. cruzi infection.

Conglomeration of novel Culex quinquefasciatus salivary proteins to contrive multi-epitope subunit vaccine against infections caused by blood imbibing transmitter.

The southern house vector, Culex quinquefasciatus is the paramount cause of Japanese encephalitis, West Nile fever and Lymphatic Filariasis, which is globally affecting the worldwide population. Many attempts were made by researchers with different perceptions to discover regimen against these aforementioned ailments but the output was not that effectual. Consequently, there is an imminent need to develop very effective and potential treatment against these perilous diseases. Employing immunoinformatic approaches, we have designed the multi-epitope subunit vaccine by exploring salivary proteins of Culex quinquefasciatus, which possess both antigenic and potent immunogenic behaviour. The immunogenic epitopes from the immune cells (B-cell, CTL, and HTL) were predicted and linked together with the help of linkers. Apart from this, at the N-terminal of the construct, an adjuvant was added in order to enhance the immunogenicity of the vaccine. The physiological parameters, antigenicity and allergenicity were also evaluated for the designed vaccine construct. Molecular docking between ligand (vaccine construct) and TLR-4 receptor was performed. Molecular dynamics simulation of the docked complex was performed to identify the stability, patterns, macromolecules interactions and their behaviour. Finally, to ensure the translation and gene expression efficiency of designed construct, insilico restriction cloning was executed into suitable expression vector pET28a.

Scrutinizing Mycobacterium tuberculosis membrane and secretory proteins to formulate multiepitope subunit vaccine against pulmonary tuberculosis by utilizing immunoinformatic approaches.

Tuberculosis is a menacing disease caused eminently to the people inhabiting the tropical and sub-tropical nations. A holistic approach is required to generate T and B memory cells to effectuate a long-term exemption from the pulmonary tuberculosis. In this study, immunoinformatic approaches were used to design a multi-epitope-based subunit vaccine for pulmonary tuberculosis which may improve human immune system. The various B-cell, TH cell and TC cell binding epitopes were predicted for selected 2 membrane and 12 secretory proteins of Mycobacterium tuberculosis. The final vaccine construct was assembled by merging the predicted epitope sequences and an adjuvant at the N-terminal of the construct. Furthermore, the physiochemical characterization was done to check the molecular weight, aliphatic index, theoretical PI, hydropathicity and thermostable nature of the designed vaccine. The construct was a potential antigen while wasn't allergenic in nature. Tertiary modeling was performed, by filtering them a refined model was chosen and was docked with TLR-4 (immune receptor). Molecular docking and dynamic simulation was performed and the microscopic interaction between the vaccine construct (ligand) and TLR-4 receptor complex was verified. In silico cloning was used to fortify the expression and translation efficiency of the vaccine within an expression vector.

Excavating chikungunya genome to design B and T cell multi-epitope subunit vaccine using comprehensive immunoinformatics approach to control chikungunya infection.

Chikungunya infection has been a cause of countless deaths worldwide. Due to lack of permanent treatment and prevention of this disease, the mortality rate remains very high. Therefore, we followed an immunoinformatics approach for the development of multi-epitope subunit vaccine which is able to elucidate humoral, cell-mediated and innate immune responses inside the host body. Both structural and non-structural proteins of chikungunya virus were utilized for prediction of B-cell and T-cell binding epitopes along with interferon-γ (IFN-γ) inducing epitopes. The vaccine construct is composed of ß-defensin as an adjuvant at the N-terminal followed by Cytotoxic T-Lymphocytes (CTL) and Helper T-Lymphocyte (HTL) epitopes. The same vaccine construct was also utilized for the prediction of B-cell binding epitopes and IFN-γ inducing epitopes. This was followed by the 3D model generation, refinement and validation of the vaccine construct. Later on, the interaction of modeled vaccine with the innate immune receptor (TLR-3) was explored by performing molecular docking and molecular dynamics simulation studies. Also to check the efficiency of expression of this vaccine construct in an expression vector, in silico cloning was performed at the final stage of vaccine development. Further, designed multi-epitope subunit vaccine necessitates experimental and clinical investigation to develop as an immunogenic vaccine candidate.

Exploring Leishmania secretory proteins to design B and T cell multi-epitope subunit vaccine using immunoinformatics approach.

Visceral leishmaniasis (VL) is a fatal form of leishmaniasis which affects 70 countries, worldwide. Increasing drug resistance, HIV co-infection, and poor health system require operative vaccination strategy to control the VL transmission dynamics. Therefore, a holistic approach is needed to generate T and B memory cells to mediate long-term immunity against VL infection. Consequently, immunoinformatics approach was applied to design Leishmania secretory protein based multi-epitope subunit vaccine construct consisting of B and T cell epitopes. Further, the physiochemical characterization was performed to check the aliphatic index, theoretical PI, molecular weight, and thermostable nature of vaccine construct. The allergenicity and antigenicity were also predicted to ensure the safety and immunogenic behavior of final vaccine construct. Moreover, homology modeling, followed by molecular docking and molecular dynamics simulation study was also performed to evaluate the binding affinity and stability of receptor (TLR-4) and ligand (vaccine protein) complex. This study warrants the experimental validation to ensure the immunogenicity and safety profile of presented vaccine construct which may be further helpful to control VL infection.

Exploring dengue genome to construct a multi-epitope based subunit vaccine by utilizing immunoinformatics approach to battle against dengue infection.

Dengue is considered as a major health issue which causes a number of deaths worldwide each year; tropical countries are majorly affected by dengue outbreaks. It is considered as life threatening issue because, since many decades not a single effective approach for treatment and prevention of dengue has been developed. Therefore, to find new preventive measure, we used immunoinformatics approaches to develop a multi-epitope based subunit vaccine for dengue which can generate various immune responses inside the host. Different B-cell, TC cell, and TH cell binding epitopes were predicted for structural and non-structural proteins of dengue virus. Final vaccine constructs consisting of TC and TH cell epitopes and an adjuvant (ß-defensin) at N-terminal of the construct. Presence of B-cell and IFN-γ inducing epitopes confirms the humoral and cell mediated immune response developed by designed vaccine. Designed vaccine was not found allergic and was potentially antigenic in nature. Modeling of tertiary structure and the refined model was used for molecular docking with TLR-3 (immune receptor). Molecular docking and dynamics simulation confirms the microscopic interactions between ligand and receptor. In silico cloning approach was used to ensure the expression and translation efficiency of vaccine within an expression vector.

Polymeric pollutant biodegradation through microbial oxidoreductase: A better strategy to safe environment.

The detoxification of xenobiotic organic compounds by various microorganisms through oxidative coupling is facilitated with oxidoreductases. With the help of energy yielding biochemical reactions, these microbes extract energy for their metabolic pathway. They promote the transfer of electrons from a reduced organic substrate to another chemical compound. During such oxidation-reduction reactions, the toxic polymeric substance is finally oxidized into harmless compounds. Enzymatic bioremediation of toxic organic pollutant is a very effective strategy in complex environmental conditions. Oxidoreductases enzymes have a significant potential for the bioremediation of the xenobiotic compounds. Various electron donor complex polymeric substrates containing Phenol and aromatic amines are oxidized by peroxidase in the presence of H2O2 while O2 in the case of dioxygenase. This review attempts to present relevant information on the peroxidases and dioxygenase from various microbial isolates involved in the biodegradation of a wide range of pollutants.