Biology subjects

Kabra, S.

Publications and source records attributed to Kabra, S..

4 recordsLinked to original sources

bioRxiv2022

Understanding the mechanism of the SARS CoV-2 coinfection with other respiratory viruses

Coinfections have a potential role in increased morbidity and mortality rates during pandemics. Our investigation is aimed at evaluating the viral coinfection prevalence in COVID-19 patients. Rapid diagnostic tests are tools with a paramount impact both on improving patient care. Particularly in the case of respiratory infections, it is of great importance to quickly confirm/exclude the involvement of pathogens. The COVID-19 pandemic has been associated with changes in respiratory virus infections worldwide, which have differed between virus types. In this paper, we systematically searched the percentage of coinfection of various respiratory viruses in COVID-19-positive samples. We included patients of all ages, in all settings. The main outcome was the proportion of patients with viral coinfection. By describing the differences in changes between viral species across different geographies over the course of the COVID-19 pandemic, we may better understand the complex factors involved in the community cocirculation of respiratory viruses.

genomics↗

bioRxiv2021

Immunophenotyping and transcriptional profiling of human plasmablasts in dengue.

Previous studies have shown that plasmablasts expand massively in dengue patients as compared to many other situations such as influenza infection or vaccination. However, a detailed understanding of the phenotypes and transcriptional features of these cells is lacking. Moreover, despite India having nearly a third of global dengue disease burden, there is virtually no information on plasmablasts responses in dengue patients from India. Here, we provide a detailed characterization of plasmablast responses from dengue confirmed febrile children in India. Immunophenotyping and RNA seq analysis showed that in addition to secreting dengue specific antibodies, these massively expanding cells expressed several adhesion molecules, chemokines and chemokine receptors that are involved in endothelial interactions, homing to skin or mucosal tissues including intestine. Surprisingly, we found that these cells also upregulated expression of several cytokine genes that are involved in angiogenesis, leukocyte extravasation and vascular permeability. These transcriptional features were qualitatively similar to plasmablasts from influenza vaccinees. Interestingly, the expansion of the plasmablasts in dengue patients was significantly lower in patients with primary dengue infection compared to those with secondary dengue. Moreover, within the primary dengue patients, their expansion was significantly lower in patients with mild dengue infection (DI) compared to patients with dengue with warning signs (DW) or severe dengue (SD). These results significantly improve our understanding of human plasmablast responses in dengue. Importance Dengue is a globally spreading with over 100 million clinical cases annually with symptoms ranging from mild self-limiting febrile illness to more severe and sometimes life-threatening dengue hemorrhagic fever or shock, especially among children. India contributes nearly a third of global dengue disease burden. The pathophysiology of dengue is complex and remains poorly understood despite many advances indicating a key role for antibody dependent enhancement of infection. While serum antibodies have been extensively studied, the characteristics of the cellular factories responsible for antibody production, i.e., plasmablasts, are only beginning to emerge. This study provides a comprehensive understanding of the magnitude, phenotype, functional and transcriptional profiles of human plasmablasts from dengue patients in India.

immunology↗

bioRxiv2020

Integrated genomic view of SARS-CoV-2 in India

India first detected SARS-CoV-2, causal agent of COVID-19 in late January-2020, imported from Wuhan, China. March-2020 onwards; importation of cases from rest of the countries followed by seeding of local transmission triggered further outbreaks in India. We used ARTIC protocol based tiling amplicon sequencing of SARS-CoV-2 (n=104) from different states of India using a combination of MinION and MinIT from Oxford Nanopore Technology to understand introduction and local transmission. The analyses revealed multiple introductions of SARS-CoV-2 from Europe and Asia following local transmission. The most prevalent genomes with patterns of variance (confined in a cluster) remain unclassified, here, proposed as A4-clade based on its divergence within A-cluster. The viral haplotypes may link their persistence to geo-climatic conditions and host response. Despite the effectiveness of non-therapeutic interventions in India, multipronged strategies including molecular surveillance based on real-time viral genomic data is of paramount importance for a timely management of the pandemic.

microbiology↗

bioRxiv2018

Viral characteristics associated with sustenance of elite neutralizing activity in chronically HIV-1C infected monozygotic pediatric twins

Broad and potent neutralizing antibodies (bnAbs) with multiple epitope specificities evolve in HIV-1 infected children. Herein we studied two antiretroviral naive chronically HIV-1C in-fected monozygotic pediatric twins AIIMS_329 and AIIMS_330 with potent plasma bnAbs. Elite plasma neutralizing activity was observed since initial sampling at 78 months in AIIMS_330 and persisted throughout, while in AIIMS_329 it was seen at 90-months of age after which potency decreased overtime. We evaluated potential viral characteristics associated with the varied immune profile by generating single genome amplified pseudoviruses. The AIIMS_329 viruses generated from 90-month time point sampling were neutralization sensitive to second generation bnAbs and contemporaneous autologous plasma antibodies, while viruses from 112-months and 117-month timepoints were resistant to most bnAbs and autologous contemporaneous plasma. AIIMS_329 viruses developed resistance to plasma nAbs plausibly by N160-glycan loss, V1- and V4-loop lengthening. The viruses generated from AIIMS_330 at 90-month and 117-month timepoint showed varied susceptibility to bnAbs and autologous contemporaneous plasma antibodies while the viruses of 112-month timepoint, at which plasma nAb specificities mapped to the V2-glycan, V3-glycan and CD4bs, were resistant to autologous contemporaneous plasma antibodies as well as most bnAbs. We observed evolution of a viral pool in AIIMS_330 donor, comprising of plasma antibody neutralization sensitive or resistant diverse autologous viruses that in turn may have contributed to development and maintenance of elite neutralizing activity. The findings of this study provide information towards understanding factors involved in generation and maintenance of potent plasma nAbs.\n\nImportanceChronically HIV-1 infected children that develop elite neutralizing activity are suitable candidates to understand the mechanisms that lead to the co-evolution of virus and antibody response. Here, we evaluated the alterations in virus and antibody responses over time in chronically HIV-1C infected monozygotic pediatric twins, AIIMS_329 and AIIMS_330, who had acquired the infection by vertical transmission. AIIMS_330 retained the elite plasma neutralizing activity throughout, while in AIIMS_329, the potency decreased post 90 months of age. The corresponding viral pool from post 90-month samples in AIIMS_330 showed varied susceptibility, while that in AIIMS_329, developed resistance to bnAbs and autologous plasma antibodies. The findings of this study, conducted in twin children of same genetic make-up and infected at birth with a single source of HIV-1C, suggest that a viral pool with varied susceptibility to antibodies could have been one of the factors responsible for sustained elite neutralizing activity in AIIMS_330.

immunology↗