Expression of dengue capsid-like particles in silkworm and display of envelope domain III of dengue virus serotype 2.

Dengue virus (DENV) is a considerable public health threat affecting millions of people globally. Vaccines for dengue are an important strategy to reduce the disease burden. We expressed capsid (C2) and envelope domain III of dengue virus serotype 2 (2EDIII) separately in the silkworm expression system. We conjugated them employing the monomeric streptavidin (mSA2) and biotin affinity to display the antigenic 2EDIII on the C2-forming capsid-like particle (CLP). Purified 2EDIII-displaying C2 (CLP/2EDIII) was immunogenic in BALB/c mice, eliciting neutralizing antibodies confirmed by a single-round infectious particle (SRIP) neutralization assay. Th1 cytokine levels were upregulated for the CLP/2EDIII group, and the anti-inflammatory IL-10 and pro-inflammatory IL-6 cytokine levels were also raised compared to the 2EDIII and the control groups. Elevated cytokine levels for CLP/2EDIII indicate the importance of displaying the 2EDIII as CLP/2EDIII rather than as an individual subunit. This study is the first to express the C2 protein as self-assembling CLP in vivo and 2EDIII separately in the silkworm expression system and conjugate them to form a monovalent CLP. Thus, this CLP/2EDIII display method may pave the way for an efficient tetravalent dengue vaccine candidate.

Oxidative stress response in the pathogenesis of dengue virus virulence, disease prognosis and therapeutics: an update.

Dengue virus (DENV) is a mosquito-borne arbovirus that causes febrile illness and can lead to a potentially lethal disease. The mechanism of disease pathogenesis is not completely understood, and there are currently no vaccines or therapeutic drugs available to protect against all four serotypes of DENV. Although many reasons have been suggested for the development of the disease, dengue studies have shown that, during DENV infection, there is an imbalance between oxidants and antioxidants that disrupts homeostasis. An increase in reactive oxygen species (ROS) levels triggers the sudden release of cytokines, which can lead to plasma leakage and other severe symptoms. In the present review, we give an overview of the oxidative stress response and its effect on the progression of dengue disease. We also discuss the role of oxidative-stress-associated molecules in disease prognostic and therapeutics.

Altered Platelet Fatty Acids in Dengue Cases by Gas Chromatography-Mass Spectrometry Analysis.

BACKGROUND: The role of dengue virus in altering the functional properties of platelets remains poorly understood. Few studies have observed that changes in fatty acids are found to have an effect on platelet activation and aggregation. Also, platelet fatty acids have not been extensively studied in dengue so far. So, we aimed to study the fatty acids of platelet membranes in patients with dengue. METHODS: Gas chromatography-mass spectrometry (GC-MS) method was used to analyze fatty acids in the lipid extracts of platelets isolated from the study participants. RESULTS: GC-MS analysis of platelet lipids identified and quantified nearly 23 unique lipid molecules on platelet membrane. We observed significant alterations with some of the fatty acids in patients with dengue compared to controls. Within dengue cases, increase in unsaturated fatty acids in severe dengue was observed compared to non-severe dengue. From baseline to defervescence, no difference in fatty acids was observed in dengue platelets. This indicates that in dengue, platelet physiology remains altered even after the febrile phase. CONCLUSION: To the best of our knowledge, this is the first study characterizing the differential expression of platelet fatty acids in dengue infection. However, further studies are warranted to expound the underlying cause for thrombocytopenia and platelet dysfunction in dengue.

Lipid peroxidation, DNA damage, and apoptosis in dengue fever.

Interplay between the apoptosis, DNA damage, and oxidative stress as a host response to dengue viral infections remains unclear. Peripheral blood mononuclear cells (PBMCs) were isolated from 60 dengue infected patients, 20 patients with febrile illness other than dengue (OFI) and 10 non-febrile illness (NFI) patients. DNA damage in the PBMCs was assessed using single cell gel electrophoresis and stages of apoptosis underwent by the PBMCs were studied by Annexin-PI staining using flow cytometry. Plasma levels of malondialdehyde levels were estimated using thiobarbituric acid assay. Dengue infected individuals had showed increased DNA damage than NFI and OFI controls at the time of admission. Annexin-PI staining revealed increased frequency of apoptotic cells in dengue infected PBMCs than controls during the admission time. Similar pattern was observed in samples collected around defervescence. Within the dengue cases, percentage of live cells was higher in non-severe dengue than severe dengue at both the time points. Follow-up samples in dengue showed less number of live cells and higher percentage of apoptotic cells with respect to their baseline and this was reversed in case of OFI. Plasma malondialdehyde levels were found to be relatively higher in dengue cases than controls at admission and around defervescence. Significant positive correlation between DNA damage, apoptosis, and plasma malondialdehyde levels might pave a way for understanding the complex interactions between virus and hosts response thereby aids in identifying plausible immunopathological links contributing to disease pathogenesis. © 2018 IUBMB Life, 70(11):1133-1143, 2018.

A Stratified Analysis of Clinical Manifestations and Different Diagnostic Methods of Neurocysticercosis-Suspected Tamilian Population Residing in and Around Puducherry.

INTRODUCTION: Human beings are accidental hosts for Cysticercus cellulosae showing varied clinical manifestations based on the site harbored by the parasitic cyst because of which disease profile remains unexplored at large. Besides this, diagnosis of the disease with a single conventional method is problematic due to lack of specificity and sensitivity. AIM: To assess the varied clinical manifestations and stratify based on imaging and serological methods for diagnosis of Neurocysticercosis (NCC) in our study population. MATERIALS AND METHODS: A hospital-based study was carried out at Jawaharlal Institute of Post-Graduate Medical Education and Research (JIPMER), the tertiary care centre caters patients from Puducherry and surrounding regions of Tamil Nadu. This is a cross-sectional analysis of clinically and radiologically suspected cases of NCC (n=119) for a period of three years (2012 to 2015). The collection of detailed clinical history and imaging findings (MRI or CT) along with the lifestyle parameters was done after obtaining informed consent. Enzyme-Linked Immune-Electro Transfer Blot (EITB) was carried out for the samples collected from study subjects. RESULTS: Based on dietary and environmental factors non-vegetarians, pork eaters, raw vegetable consumers and open-field defecation showed significant seropositivity. The clinical manifestations like seizures, blurring of vision and chronic headache with nausea followed by neck pain, cognitive deficits and movement disorder have higher seropositivity respectively. Generalized seizures were found to be more than focal seizures. While comparing the imaging and serological tests for NCC diagnosis, the positivity rate was 46.2% considering positive by both methods; but 18.5% of sero-positive cases were imaging negative, and 16% of the sero-negative cases were imaging positive. The study showed a predominance of multiple cysts (62%) in cases with cystic lesions. CONCLUSION: This study is first of its kind in associating varied and less commonly explored clinical manifestations with two different diagnostic measures in practice and its importance among our study settings. These manifestations must be considered as strong disease entities of NCC, which has to be suggested for differential diagnosis, and cannot be left ignored. Combinatorial diagnostic methods like serology and imaging techniques should be followed in diagnosis and assessing the disease burden.