The ongoing COVID-19 pandemic highlights the need to tackle viral variants, expand the number of antigens, and assess diverse delivery systems for vaccines against emerging viruses. In the present ...study, a DNA vaccine candidate was generated by combining in tandem envelope protein domain III (EDIII) of dengue virus serotypes 1–4 and a dengue virus (DENV)-2 non-structural protein 1 (NS1) protein-coding region. Each domain was designed as a serotype-specific consensus coding sequence derived from different genotypes based on the whole genome sequencing of clinical isolates in India and complemented with data from Africa. This sequence was further optimized for protein expression. In silico structural analysis of the EDIII consensus sequence revealed that epitopes are structurally conserved and immunogenic. The vaccination of mice with this construct induced pan-serotype neutralizing antibodies and antigen-specific T cell responses. Assaying intracellular interferon (IFN)-γ staining, immunoglobulin IgG2(a/c)/IgG1 ratios, and immune gene profiling suggests a strong Th1-dominant immune response. Finally, the passive transfer of immune sera protected AG129 mice challenged with a virulent, non-mouse-adapted DENV-2 strain. Our findings collectively suggest an alternative strategy for dengue vaccine design by offering a novel vaccine candidate with a possible broad-spectrum protection and a successful clinical translation either as a stand alone or in a mix and match strategy.
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Developing a successful vaccine against dengue has been challenging. Arun Sankaradoss and colleagues developed a genotype-specific DNA DENV vaccine candidate that elicits robust dengue immune responses. The low cost and thermostability of DNA vaccines should allow countries to implement large-scale vaccination programs, which could greatly reduce dengue cases.
The amaranthine scale of the COVID-19 pandemic and unpredictable disease severity is of grave concern. Serological diagnostic aids are an excellent choice for clinicians for rapid and easy prognosis ...of the disease. To this end, we studied the humoral immune response to SARS-CoV-2 infection to map immunogenic regions in the SARS-CoV-2 proteome at amino acid resolution using a high-density SARS-CoV-2 proteome peptide microarray. The microarray has 4932 overlapping peptides printed in duplicates spanning the entire SARS-CoV-2 proteome. We found 204 and 676 immunogenic peptides against IgA and IgG, corresponding to 137 and 412 IgA and IgG epitopes, respectively. Of these, 6 and 307 epitopes could discriminate between disease severity. The emergence of variants has added to the complexity of the disease. Using the mutation panel available, we could detect 5 and 10 immunogenic peptides against IgA and IgG with mutations belonging to SAR-CoV-2 variants. The study revealed severity-based epitopes that could be presented as potential prognostic serological markers. Further, the mutant epitope immunogenicity could indicate the putative use of these markers for diagnosing variants responsible for the infection.
Introduction: Dengue and Chikungunya fever are arboviral diseases which are spread by a common vector. Being clinically indistinguishable, it is necessary to distinguish both either by molecular or ...serology testing. Aim: To estimate the seroprevalence of Dengue and Chikungunya mono-infection as well as dual infection in patients with acute febrile illness. Materials and Methods: Two hundred patients with acute febrile illness were enrolled from April 2015 to October 2016. Detailed clinical history was documented. Samples were collected and subjected to Polymerase Chain Reaction (PCR) and Enzyme Linked Immuno Sorbent Assay (ELISA) testing. For qualitative data, frequency percentage table was used and association was done using Chi-square test. Results: Out of 200 patients, 8.5% had Chikungunya mono-infection and 41.5% patients had Dengue mono-infection. Dengue and Chikungunya co-infection was found in 4.5% patients. Most affected age group was 18-60 years wherein male preponderance was seen. In Chikungunya fever, 82.4% had morning stiffness and 35.3% had joint swelling; elbow and knee were the most commonly affected joints. In Chikungunya fever, 76.5% patients had restricted joint movements and 52.9% had Visual Analog Score (VAS) of 6-10. In Dengue fever, myalgia (67.5%) and rash (20.5%) were common symptoms. A total of 61.4% patients of Dengue fever had low platelet count. All Chikungunya cases and 88.1% Dengue cases detected by PCR had fever duration of less than five days. 85% of Chikungunya and 69% of Dengue cases detected by IgM ELISA had fever duration of more than five days. Conclusion: Diagnostic algorithms of acute febrile illness cases should include testing by both molecular and serology for both the viruses, which is the absolute need of the hour.
In recent times, Plasmodium vivax (P. vivax) has become a serious threat to public health due to its ability to cause severe infection with fatal outcomes. Its unique biology makes it resilient to ...control measures that are otherwise effective against P. falciparum. A deeper understanding of P. vivax biology and pathogenesis is, therefore, essential for developing the right control strategies. Proteomics of P. falciparum has been helpful in studying disease biology and elucidating molecular mechanisms involved in the development of disease. However, unlike P. falciparum, proteomics data for P. vivax infection is minimal due to the absence of a continuous culture system. The dependence on clinical samples and animal models has drastically limited P. vivax research, creating critical knowledge gaps in our understanding of the disease. This study describes an in-depth proteomics analysis of P. vivax-infected human plasma and parasite isolates, to understand parasite biology, pathogenesis, and to identify new diagnostic targets for P. vivax malaria.
A mass-spectrometry- (MS) based proteomics approach (Q Exactive) was applied to analyze human plasma and parasite isolates from vivax malaria patients visiting a primary health centre in India. Additionally, a targeted proteomics assay was standardized for validating unique peptides of most recurring parasite proteins.
Thirty-eight P. vivax proteins were detected in human plasma with high confidence. Several glycolytic enzymes were found along with hypothetical, cytoskeletal, ribosomal, and nuclear proteins. Additionally, 103 highly abundant P. vivax proteins were detected in parasite isolates. This represents the highest number of parasite proteins to be reported from clinical samples so far. Interestingly, five of these; three Plasmodium exported proteins (PVX_003545, PVX_003555 and PVX_121935), a hypothetical protein (PVX_083555) and Pvstp1 (subtelomeric transmembrane protein 1, PVX_094303) were found in both plasma and parasite isolates.
A parasite proteomics investigation is essential to understand disease pathobiology and design novel interventions. Control strategies against P. vivax also depend on early diagnosis. This work provides deeper insights into the biology of P. vivax by identifying proteins expressed by the parasite during its complex life-cycle within the human host. The study also reports antigens that may be explored as diagnostic candidates.
Integrin α
4
β
7
expressing CD4
+
T cells are preferred targets for HIV infection and are thought to be predictors of disease progression. Concurrent analysis of integrin α
4
β
7
expressing innate ...and adaptive immune cells was carried out in antiretroviral (ART) therapy naïve HIV infected women in order to determine its contribution to HIV induced immune dysfunction. Our results demonstrate a HIV infection associated decrease in the frequency of integrin α
4
β
7
expressing endocervical T cells along with an increase in the frequency of integrin α
4
β
7
expressing peripheral monocytes and central memory CD4
+
T cells, which are considered to be viral reservoirs. We report for the first time an increase in levels of soluble MAdCAM-1 (sMAdCAM-1) in HIV infected individuals as well as an increased frequency and count of integrin
β
7
Hi
CD8
+
memory T cells. Correlation analysis indicates that the frequency of effector memory CD8
+
T cells expressing integrin α
4
β
7
is associated with levels of both sMAdCAM-1 and TGF-β1. The results of this study also suggest HIV induced alterations in T cell homeostasis to be on account of disparate actions of sMAdCAM-1 and TGF-β1 on integrin α
4
β
7
expressing T cells. The immune correlates identified in this study warrant further investigation to determine their utility in monitoring disease progression.
The multi-country mpox outbreak across the globe has led to the systematic surveillance of mpox cases in India. During the surveillance of mpox, we encountered cases of Varicella Zoster Virus (VZV) ...in suspected mpox cases amongst children & adults. This study focused on the genomic characterization of VZV in India.
A total of 331 mpox suspected cases were tested for VZV through real-time PCR, and the positive samples were subjected to next-generation sequencing to retrieve the whole genome of VZV using CLC genomics software. Phylogenetic analysis has been done in MEGA 11.0 software to identify circulating clades.
Of the 331 suspected cases, 28 cases with vesicular rashes were found to be positive for VZV. The maximum genome could be retrieved from the clinical specimens of 16 cases with coverage greater than 98% when mapped with reference strain Dumas (NC 001348). The phylogenetic analyses of these sequences determined the circulation of clades 1, 5, and 9 in India. Further, the sequence analysis demonstrated non-synonymous single nucleotide polymorphism (SNPs) among specific ORF of VZV including ORF 14, ORF 22, ORF 36, ORF 37 and ORF 51. Although clade 1 and 5 has been reported earlier, the circulation of clade 9 of VZV has been determined for the first time in India.
Although the circulation of different clades of VZV was reported from India, the presence of clade 9 was detected for the first time during the mpox surveillance.
Knowledge of the prevalence of latent Mycobacterium tuberculosis infection is crucial for effective tuberculosis control, but tuberculin skin test surveys have major limitations, including poor ...specificity because of the broad antigenic cross-reactivity of tuberculin. The M. tuberculosis RD1 genomic segment encodes proteins, such as early secretory antigenic target (ESAT)-6, that are absent from M. bovis bacille Calmette-Guérin (BCG) and most environmental mycobacteria. We recently identified circulating ESAT-6-specific T cells as an accurate marker of M. tuberculosis infection. Here, interferon-γ-secreting T cells specific for peptides derived from ESAT-6 and a second RD1 gene product, CFP10, were enumerated in 100 prospectively recruited healthy adults in Bombay (Mumbai), India. Eighty percent responded to ⩾1 antigen, and many donors had high frequencies of T cells that were specific for certain immunodominant peptides. In contrast, of 40 mostly BCG-vaccinated, United Kingdom-resident healthy adults, none responded to either antigen. This study suggests an 80% prevalence of latent M. tuberculosis infection in urban India.
The B.1.1.7 (Alpha) variant has been detected in Mumbai, India during February 2021. Subsequently, we retrieved 43 sequences from specimens of 51 COVID-19 cases from Mumbai. The sequence analysis ...revealed that the cases were mainly affected with Alpha variant which suggests its role in community transmission of SARS-CoV-2 in Mumbai, India.
Due to the failure of virus isolation of the Omicron variant in Vero CCL-81 from the clinical specimens of COVID-19 cases, an initial in vivo and subsequent in vitro approach was utilized for the ...isolation of the virus. A total of 74 oropharyngeal/nasopharyngeal specimens were collected from SARS-CoV-2 positive international travellers and a contact case at Delhi and Mumbai, India. All the specimens were sequenced using next-generation sequencing and simultaneously inoculated onto Vero CCL-81 cells for virus isolation. Subsequently, two omicron positive specimens were inoculated into Syrian hamsters for two passages. The initial passage of the positive hamster specimens was inoculated onto Vero CCL-81 cells. The clinical specimens, hamster specimens, and Vero CCL-81 passages were sequenced to assess the mutational changes in different host species. The replication of the Omicron variant in hamsters was confirmed with the presence of a high viral load in nasal turbinate and lung specimens of both passages. The successful isolation of the virus from hamster specimens with Vero CCL-81 was observed with cytopathic effect in infected cells and high viral load in the cell suspension. The genome analysis revealed the presence of L212C mutation, Tyrosine 69 deletion, and C25000T nucleotide change in spike gene of hamster passage sequences and an absence of V17I mutation in E gene in hamster passage sequences, unlike human clinical specimen and Vero CCL-81 passages. No change was observed in the furin cleavage site in any of the specimen sequences, suggesting intact pathogenicity of the virus isolate. Our data demonstrated successful isolation of the Omicron variant with the in vivo method first followed by in vitro method. The virus isolate could be used in the future to explore different aspects of the Omicron variant.
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