Biology subjects

Shete, A. M.

Publications and source records attributed to Shete, A. M..

7 recordsLinked to original sources

bioRxiv2022

Substantial immune response in Omicron infected breakthrough and unvaccinated individuals against SARS-CoV-2 variants of concerns

The recent emergence of highly mutated SARS-CoV-2 Omicron variant has debilitating effect on public health system of the affected countries worldwide. Currently India is facing third wave of COVID-19 pandemic and going through a severe crisis. Within short span of time, the variant has shown high transmissibility and capability of evading the immune response generated against natural infection and vaccination. The immune escape potential of Omicron is a serious concern and further needs to be explored. In the present study, we have assessed the IgG and neutralizing antibody (NAb) response in breakthrough individuals vaccinated with two doses ChAdOx1 nCoV-19 vaccine (n=25), breakthrough individuals vaccinated with two doses of BNT162b2 mRNA vaccine (n=8) and unvaccinated individuals (n=6). All these individuals were infected with Omicron variant. The IgG antibody activity in the sera of the ChAdOx1 nCoV-19 and BNT162b2 mRNA breakthrough individuals was comparable with S1-RBD, while it was lesser in BNT162b2 mRNA breakthrough individuals with N protein and inactivated whole antigen IgG ELISA. BNT162b2 mRNA breakthrough individuals showed moderate reduction in NAb GMTs compared to ChAdOx1 nCoV-19 against Alpha, Beta and Delta. However, 3-fold higher reduction was observed with omicron variant in BNT162b2 mRNA than ChAdOx1 nCoV-19. Apparently, Alpha variant was modestly resistant to the sera of unvaccinated individuals than Beta, Delta and Omicron. Our study demonstrated substantial immune response in the individuals infected with Omicron. The neutralizing antibodies could effectively neutralize the Omicron and other VOCs including the most prevalent Delta variant.

microbiology↗

bioRxiv2022

Pathogenicity of SARS-CoV-2 Omicron in Syrian hamsters and its neutralization with different Variants of Concern

SARS-CoV-2 Omicron variant is rampantly spreading across the globe. Animal models are useful in understanding the disease characteristics as well as properties of emerging SARS-CoV-2 variants. We assessed the pathogenicity and immune response generated by BA.1 sub-lineage of SARS-CoV-2 Omicron variant with R346K mutation in 5 to 6-week old Syrian hamsters. Virus shedding, organ viral load, lung disease and immune response generated were sequentially assessed. The disease characteristics of Omicron were found to be similar to that of other SARS-CoV-2 variants of concerns in hamsters like high viral replication in the respiratory tract and interstitial pneumonia. The infected hamsters demonstrated lesser body weight gain in comparison to the uninfected control hamsters. Viral RNA could be detected in nasal washes and respiratory organs (nasal turbinate, trachea, bronchi and lungs) till 10 and 14 days respectively. The clearance of the virus was observed from nasal washes and lungs by day 7. Neutralizing antibody response against Omicron variant was detected from day 5 with rising antibody titers till 14 days. However, the cross-neutralization titre of the sera against other variants showed severe reduction ie., 7 fold reduction against Alpha and no titers against B.1, Beta and Delta. This preliminary data shows that Omicron variant infection can produce moderate to severe lung disease and the neutralizing antibodies produced in response to Omicron variant infection shows poor neutralizing ability against other co-circulating SARS-CoV-2 variants like Delta which necessitates caution as it may lead to increased cases of reinfection.

microbiology↗

bioRxiv2022

An in vitro and in vivo approach for the isolation of Omicron variant from human clinical specimens

Due to failure of virus isolation of Omicron variant in Vero CCL-81 from the clinical specimens of COVID-19 cases, we infected Syrian hamsters and then passage into Vero CCL-81 cells. The Omicron sequences were studied to assess if hamster could incorporate any mutation to changes its susceptibility. L212C mutation, Tyrosine 69 deletion, and C25000T nucleotide change in spike gene and absence of V17I mutation in E gene was observed in sequences of hamster passage unlike human clinical specimen and Vero CCL-81 passages. No change was observed in the furin cleavage site in any of the specimen sequence which suggests usefulness of these isolates in future studies.

microbiology↗

bioRxiv2021

SARS-CoV-2 Delta derivatives impact on neutralization of Covishield recipient sera

The emergence of SARS-CoV-2 Delta variant and its derivatives has created grave public health problem worldwide. The high transmissibility associated with this variant has led to daily increase in the number of SARS-CoV-2 infections. Delta variant has slowly dominated the other variants of concern. Subsequently, Delta has further mutated to Delta AY.1 to Delta AY.126. Of these, Delta AY.1 has been reported from several countries including India and considered to be highly infectious and probable escape mutant. Considering the possible immune escape, we had already evaluated the efficacy of the BBV152 against Delta and Delta AY.1 variants. Here, we have evaluated the neutralizing potential of sera of COVID-19 naive vaccinees (CNV) immunized with two doses of vaccine, COVID-19 recovered cases immunized with two doses of vaccine (CRV) and breakthrough infections (BTI) post immunization with two doses of vaccine against Delta, Delta AY.1 and B.1.617.3 using 50% plaque reduction neutralization test (PRNT50). Our study observed low NAb titer in CNV group against all the variants compared to CRV and BTI groups. Delta variant has shown highest reduction of 27.3-fold in NAb titer among CNV group compared to other groups and variants. Anti-S1-RBD IgG immune response among all the groups was also substantiated with NAb response. Compromised neutralization was observed against Delta and Delta AY.1 compared B.1 in all three groups. However, it provided protection against severity of the disease and fatality.

molecular biology↗

bioRxiv2021

Neutralization against B.1.351 and B.1.617.2 with sera of COVID-19 recovered cases and vaccinees of BBV152

Recently, multiple SARS-CoV-2 variants have been detected across the globe. The recent emergence of B.1.617 lineage has created serious public health problem in India. The high transmissibility was observed with this lineage which has led to daily increase in the number of SARS-CoV-2 infections. Apparently, the sub-lineage B.1.617.2 has slowly dominated the other variants including B1617.1, B.617.3 and B.1.1.7. With this, World Health Organization has described B.1.617.2 as variant of concern. Besides this, variant of concern B.1.351 has been also reported from India, known to showreducedefficacyfor many approved vaccines. With the increasing threat of the SARS-CoV-2 variants, it is imperative to assess the efficacy of the currently available vaccines against these variants. Here, we have evaluated the neutralization potential of sera collected from COVID-19 recovered cases (n=20) and vaccinees with two doses of BBV152 (n=17) against B.1.351 and B.1.617.2 compared to the prototype B.1 (D614G) variant.The finding of the study demonstrated a reduction in neutralization titers with sera of COVID-19 recovered cases(3.3-fold and 4.6-fold) and BBV152 vaccinees (3. 0 and 2.7 fold) against B.1.351 and B.1.617.2 respectively.Although, there is reduction in neutralization titer, the whole-virion inactivated SARS-CoV-2 vaccine (BBV152) demonstrates protective response against VOC B.1351 and B.1.617.2.

microbiology↗

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

Neutralization of variant under investigation B.1.617 with sera of BBV152 vaccinees

The drastic rise in the number of cases in Maharashtra, India has created a matter of concern for public health experts. Twelve isolates of VUI lineage B.1.617 were propagated in VeroCCL81 cells and characterized. Convalescent sera of the COVID-19 cases and recipients of BBV152 (Covaxin) were able to neutralize VUI B.1.617.

immunology↗