Biology subjects

Kadam, M.

Publications and source records attributed to Kadam, M..

3 recordsLinked to original sources

bioRxiv2021

SARS CoV-2 variant B.1.617.1 is highly pathogenic in hamsters than B.1 variant

BackgroundThe recent emergence of new SARS-CoV-2 lineage B.1.617 in India has been associated with a surge in the number of daily infections. This variant has combination of specific mutations L452R, E484Q and P681R reported to possibly enhance the transmissibility with likelihood of escaping the immunity. We investigated the viral load and pathogenic potential of B.1.617.1 in Syrian golden hamsters. MethodsTwo groups of Syrian golden hamsters (9 each) were inoculated intranasally with SARS CoV-2 isolates, B.1 (D614G) and B.1.617.1 respectively. The animals were monitored daily for the clinical signs and body weight. The necropsy of three hamsters each was performed on 3, 5- and 7-days post-infection (DPI). Throat swab (TS), nasal wash (NW) and organ samples (lungs, nasal turbinate, trachea) were collected and screened using SARS-CoV-2 specific Real-time RT-PCR. ResultsThe hamsters infected with B.1.617.1 demonstrated increased body weight loss compared to B.1 variant. The highest viral load was observed in nasal turbinate and lung specimens of animals infected with B.1.167.1 on 3 DPI. Neutralizing antibody (NAb) and IgG response in hamsters of both the groups were observed from 5 and 7 DPI respectively. However, higher neutralizing antibody titers were observed against B.1.167.1. Gross pathology showed pronounced lung lesions and hemorrhage with B.1.671 compared to B.1. ConclusionsB.1617.1 and B.1 variant varied greatly in their infectiousness, pathogenesis in hamster model. This study demonstrates higher pathogenicity in hamsters evident with reduced body weight, higher viral load in lungs and pronounced lung lesions as compared to B.1 variant. SummaryB.1.617.1 is the new SARS-CoV-2 lineage that emerged in India. Maximal body weight loss and higher viral load in hamsters infected with B.1.617.1. It caused pronounced lung lesions in hamsters compared to B.1 variant which demonstrates the pathogenic potential of B.1.617.1.

microbiology↗

bioRxiv2021

Vaccine Hyporesponse Induced By Individual Antibiotic Treatment In Mice And Non-Human Primates Is Diminished Upon Recovery Of The Gut Microbiome

Emerging evidence demonstrates a connection between microbiome composition and suboptimal response to vaccines (vaccine hyporesponse). Harnessing the interaction between microbes and the immune system could provide novel therapeutic strategies for improving vaccine response. Currently we do not fully understand the mechanisms and dynamics by which the microbiome influences vaccine response. Using both mouse and non-human primate models, we report that short-term oral treatment with a single antibiotic (vancomycin) results in disruption of the gut microbiome and this correlates with a decrease in systemic levels of antigen-specific IgG upon subsequent parenteral vaccination. We further show that recovery of microbial diversity before vaccination prevents antibiotic-induced vaccine hyporesponse, and that the antigen specific IgG response correlates with the recovery of microbiome diversity. RNA-sequencing analysis of small intestine, spleen, whole blood, and secondary lymphoid organs from antibiotic treated mice revealed a dramatic impact on the immune system, and a muted inflammatory signature is correlated with loss of bacteria from Lachnospiraceae, Ruminococcaceae, and Clostridiaceae. These results suggest that microbially modulated immune pathways may be leveraged to promote vaccine response and will inform future vaccine design and development strategies. ImportanceAntibiotic-induced gut microbiome disruption has been linked to reduced vaccine efficacy. Despite these observations, there remains a knowledge gap in the specific mechanisms by which antibiotics and the gut microbiome influence vaccine efficacy. We aim to contribute to the fields growing mechanistic understanding by presenting a detailed analysis of antibiotic treatment and recovery as it relates to vaccine response and the microbiome. Using animal models, we show that short-term antibiotic treatment prior to vaccination results in diminished vaccine-specific immune responses, and that these are correlated with specific microbiome signatures. We also demonstrate the converse, in which gut microbiome recovery can result in improved vaccine response. We further reveal that antibiotics can significantly alter multiple relevant immune pathways and this alteration in immune tone may contribute to the vaccine hyporesponse. We expect our findings will enable the continued prosecution of the role of the microbiome in modulating the host immune system.

immunology↗

bioRxiv2021

Comparison of the pathogenicity and virus shedding of SARS CoV-2 VOC 202012/01 and D614G variant in hamster model

The emergence of SARS-CoV-2 variants has posed a serious challenge to public health system and vaccination programs across the globe. We have studied the pathogenicity and virus shedding pattern of the SARS-CoV-2 VOC 202012/01 and compared with D614G variant in Syrian hamsters. VOC 202012/01 could produce disease in hamsters characterized by body weight loss and respiratory tract tropism but mild lung pathology. Further, we also documented that neutralizing antibodies developed against VOC 202012/01 could equally neutralize D614G variant. Higher load of VOC 202012/01 in the nasal wash specimens was observed during the first week of infection outcompeting the D614G variant. The findings suggest increased fitness of VOC 202012/01 to the upper respiratory tract which could lead to higher transmission. Further investigations are needed to understand the transmissibility of new variants. One-Sentence SummarySARS-CoV-2 VOC 202012/01 infected hamsters demonstrated high viral RNA shedding through the nasal secretions and significant body weight loss with mild lung pathology compared to the D614G variant.

microbiology↗