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1.
Virology ; 584: 38-43, 2023 07.
Статья в английский | MEDLINE | ID: covidwho-2322407

Реферат

Over time, the SARS-CoV-2 virus has acquired several genetic mutations, particularly on the receptor-binding domain (RBD) spike glycoprotein. The Omicron variant is highly infectious, with enhanced immune escape activity, and has given rise to various sub-lineages due to mutations. However, there has been a sudden increase in COVID-19 reports of the Omicron subvariant BF.7 (BA.2.75.2), which has the highest number of reported cases, accounting for 76.2% of all cases worldwide. Hence, the present systematic review aimed to understand the viral mutations and factors associated with the increase in the reports of COVID-19 cases and to assess the effectiveness of vaccines and mAbs against the novel Omicron variant BF.7. The R346T mutation on the spike glycoprotein RBD might be associated with increased infection rates, severity, and resistance to vaccines and mAbs. Booster doses of COVID-19 vaccination with bivalent mRNA booster vaccine shots are effective in curtailing infections and decreasing the severity and mortality by enhancing the neutralizing antibodies (Abs) against the emerging Omicron subvariants of SARS-CoV-2, including BF.7 and future VOCs.


Тема - темы
COVID-19 Vaccines , COVID-19 , Humans , COVID-19/prevention & control , SARS-CoV-2/genetics , Vaccination , Antibodies, Monoclonal , Antibodies, Neutralizing , Spike Glycoprotein, Coronavirus/genetics , Vaccines, Combined , Glycoproteins , Antibodies, Viral
2.
J Control Release ; 357: 404-416, 2023 05.
Статья в английский | MEDLINE | ID: covidwho-2303907

Реферат

The latest omicron variants are emerging with mutations in the receptor binding domain (RBD) that confer immune evasion and resistance against current vaccines. Such variants have raised the peril of future vaccine effectiveness, as leading vaccines target the spike protein. Type-IV hypersensitivity, and other ailments due to the dominant Th1 response by leading vaccines, is also to be resolved. Therefore, vaccine that target diverse SARS-CoV-2 proteins and provide broad-spectrum protection and a balanced Th1 and Th2 response is an indispensable armament against the pandemic. In that prospect, a novel dual expression plasmid pJHL270 was developed and demonstrated the expression of omicron antigens exogenously from Salmonella and endogenously in the host cells. The simultaneous activation of MHC class I and II molecules culminated in a balanced Th1 and Th2 response, which was evident through the upsurge of IgG, IgA antibodies, IgG2a/IgG1 ratio, cytokine responses and CD4+, CD8+ T-lymphocytes. The level of CD44+ cells showed the trigger for Th1 and Th2 balance and memory-cell activation for long-lasting immunity. The level of IFN-γ + cells and neutralizing antibodies signifies the anti-viral response. The vaccine protected the hamsters from BA.5 and BA.2.75 omicron viral-challenge, exhibited a significant reduction in lung viral-load and histopathological lesions. In addition to two-way antigen expression and bilateral immune elicitation, this Salmonella-based vaccine delivery system can be prospectively applied to humans and a broad range of animals as a convenient alternative to viral and chemical vaccine delivery approaches.


Тема - темы
COVID-19 , Eukaryota , Animals , Cricetinae , Humans , SARS-CoV-2 , Salmonella/genetics , Antibodies, Neutralizing , Antibodies, Viral
3.
Cell Rep Med ; 4(4): 100991, 2023 04 18.
Статья в английский | MEDLINE | ID: covidwho-2262522

Реферат

Emerging Omicron sub-variants are causing global concerns, and their immune evasion should be monitored continuously. We previously evaluated the escape of Omicron BA.1, BA.1.1, BA.2, and BA.3 from an atlas of 50 monoclonal antibodies (mAbs), covering seven epitope classes of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) receptor-binding domain (RBD). Here, we update the atlas of totally 77 mAbs against emerging sub-variants including BQ.1.1 and XBB and find that BA.4/5, BQ.1.1, and XBB display further evasion. Besides, investigation into the correlation of binding and neutralization of mAbs reveals the important role of antigenic conformation in mAb functioning. Moreover, the complex structures of BA.2 RBD/BD-604/S304 and BA.4/5 RBD/BD-604/S304/S309 further elucidate the molecular mechanism of antibody evasion by these sub-variants. By focusing on the identified broadly potent mAbs, we find a general hotspot epitope on the RBD, which could guide the design of vaccines and calls for new broad-spectrum countermeasures against COVID-19.


Тема - темы
COVID-19 , SARS-CoV-2 , Humans , Antibodies, Monoclonal , Epitopes , Immune Evasion
4.
Sci Total Environ ; 873: 162339, 2023 May 15.
Статья в английский | MEDLINE | ID: covidwho-2267734

Реферат

This study adds insight regarding the occurrence and spread of SARS-CoV-2 Variants of Concern (VOCs) and Variants of Interest (VOIs) in Italy in October and November 2022, by testing urban wastewater collected throughout the country. A total of 332 wastewater samples were collected from 20 Italian Regions/Autonomous Provinces (APs) within the framework of national SARS-CoV-2 environmental surveillance. Of these, 164 were collected in the first week of October and 168 in the first week of November. A ∼1600 bp fragment of the spike protein was sequenced by Sanger (for individual samples) and long-read nanopore sequencing (for pooled Region/AP samples). In October, mutations characteristic of Omicron BA.4/BA.5 were detected in the vast majority (91 %) of the samples amplified by Sanger sequencing. A fraction of these sequences (9 %) also displayed the R346T mutation. Despite the low prevalence documented in clinical cases at the time of sampling, amino acid substitutions characteristic of sublineages BQ.1 or BQ.1.1 were detected in 5 % of sequenced samples from four Regions/APs. A significantly higher variability of sequences and variants was documented in November 2022, when the rate of sequences harbouring mutations of lineages BQ.1 and BQ1.1 increased to 43 %, and the number of Regions/APs positive for the new Omicron subvariant more than tripled (n = 13) compared to October. Moreover, an increase in the number of sequences with the mutation package BA.4/BA.5 + R346T (18 %), as well as the detection of variants never observed before in wastewater in Italy, such as BA.2.75 and XBB.1 (the latter in a Region where no clinical cases associated with this variant had ever been documented) was recorded. The results suggest that, as predicted by the ECDC, BQ.1/BQ.1.1 is rapidly becoming dominant in late 2022. Environmental surveillance proves to be a powerful tool for tracking the spread of SARS-CoV-2 variants/subvariants in the population.


Тема - темы
COVID-19 , Wastewater-Based Epidemiological Monitoring , Humans , SARS-CoV-2/genetics , Wastewater , COVID-19/epidemiology , Italy
5.
Cureus ; 15(2): e35261, 2023 Feb.
Статья в английский | MEDLINE | ID: covidwho-2265662

Реферат

Background SARS-CoV-2 has evolved to produce new variants causing successive waves of infection. Currently, six variants are being monitored by the World Health Organization that are replacing BA.5. These include BF.7 (BA.5 + R346T in spike), BQ.1 (and BQ.1.1, with BA.5 + R346T, K444T, N460K mutations in spike), BA.2.75 (including BA.2.75.2 and CH.1.1), and XBB (including XBB.1.5). BQ.1 and XBB variants are more immune evasive and have spread quickly throughout the world. Concerning the potential severity of infections caused by these variants, the present study describes the clinical characteristics and outcomes of these major variants in Maharashtra. Methodology A total of 1,141 reverse transcriptase-polymerase chain reaction (RT-PCR)-positive SARS-CoV-2 samples, with a cycle threshold (Ct) value of less than 25, were processed for SARS-CoV-2 whole genome sequencing between July 10, 2022, and January 12, 2023. All corresponding demographic and clinical data were recorded and analyzed using Microsoft® Excel and Epi Info™. Results Out of the 1,141 samples sequenced, BA.2.75* (63.78%) was the predominant Omicron variant, followed by the XBB* (18.88%), BA.2.38* (4.94%), BA.5* (4.06%), BA.2.10* (3.51%), and BQ.1* (1.65%). A total of 540 cases were contacted telephonically, of whom 494 (91.48%) were symptomatic with mild symptoms. Fever (77.73%) was the most common symptom, followed by cold (47.98%), cough (42.31%), and myalgia and fatigue (18.83%). Of the 540 cases, 414 (76.67%) cases recovered at home, and 126 (23.33%) were institutionally quarantined/hospitalized. Among the home-isolated and hospitalized cases, 416 (99.76%) and 108 (87.80%), respectively, recovered with symptomatic treatment, while one (0.24%) and 15 (12.20%), respectively, succumbed to the disease. Out of the 540 cases, 491 (90.93%) were vaccinated with at least one dose of the COVID-19 vaccine, 41 (7.59%) were unvaccinated, and for eight (1.48%) cases, vaccination data was not available. Conclusions The current study indicates that the XBB* variant is causing mild disease in India. However, as XBB* possesses both immune-escape and infectivity-enhancing mutations, it has the potential to spread to other parts of the world rapidly. Further, anti-SARS-CoV-2 vaccination improves survival rates in COVID-19.

6.
Infect Disord Drug Targets ; 23(4): e020323214247, 2023.
Статья в английский | MEDLINE | ID: covidwho-2277922

Реферат

The highly transmissible variation of COVID-19 has a new sub-variant known as a variant BA.2.75, which was initially discovered in India and is now found in at least 10 more countries. The World Health Organization (WHO) officials said that the new variant is actively being monitored. It has yet to be determined if the new variation is more clinically severe than its predecessors. It is known that the Omicron strain sub-variants are responsible for this rise in the worldwide COVID tally. It is too early to know if this sub-variant exhibits additional immune evasion characteristics, or is more clinically severe. The extremely contagious BA.2.75 sub-variant of Omicron has been documented in India, but there is no evidence yet that it has increased disease severity or dissemination. Many of the BA.2 lineage's sublineages form a unique collection of mutations as it evolves. A related branch of the BA.2 lineage is B.2.75. The size of genomic sequencing must be increased and maintained for the early detection of the variant strains of SARS-CoV-2. BA.2.75 is the second generation of BA.2 variations and has a high transmissibility level.


Тема - темы
COVID-19 , Humans , SARS-CoV-2 , India/epidemiology , Mutation , World Health Organization
7.
Front Med (Lausanne) ; 9: 1082846, 2022.
Статья в английский | MEDLINE | ID: covidwho-2245267

Реферат

Introduction: The emergence of the Omicron SARS-CoV-2 variant from various states of India in early 2022 has caused fear of its rapid spread. The lack of such reports from Chhattisgarh (CG), a central state in India, has prompted us to identify the Omicron circulating lineages and their mutational dynamics. Materials and methods: Whole-genome sequencing (WGS) of SARS-CoV-2 was performed in 108 SARS-CoV-2 positive combined samples of nasopharyngeal and oropharyngeal swabs obtained from an equal number of patients. Results: All 108 SARS-CoV-2 sequences belonged to Omicron of clade 21L (84%), 22B (11%), and 22D (5%). BA.2 and its sub-lineages were predominantly found in 93.5% of patients, BA.5.2 and its sub-lineage BA.5.2.1 in 4.6% of patients, and B.1.1.529 in 2% of patients. Various BA.2 sub-lineages identified were BA.2 (38%), BA.2.38 (32%), BA.2.75 (9.25%), BA.2.56, BA.2.76, and BA.5.2.1 (5% each), BA.2.74 (4.6%), BA.5.2.1 (3.7%), BA.2.43 and B.1.1.529 (1.8% each), and BA.5.2 (0.9%). Maximum mutations were noticed in the spike (46), followed by the nucleocapsid (5), membrane (3), and envelope (2) genes. Mutations detected in the spike gene of different Omicron variants were BA.1.1.529 (32), BA.2 (44), BA.2.38 (37), BA.2.43 (38), BA.2.56 (30), BA.2.74 (31), BA.2.75 (37), BA.2.76 (32), BA.5.2, and BA.5.2.1 (38 similar mutations). The spike gene showed the signature mutations of T19I and V213G in the N-terminal domain (NTD), S373P, S375F, T376A, and D405N in receptor-binding domain (RBD), D614G, H655Y, N679K, and P681H at the furin cleavage site, N764K and D796K in fusion peptide, and Q954H and N969K in heptapeptide repeat sequence (HR)1. Notably, BA.2.43 exhibited a novel mutation of E1202Q in the C terminal. Other sites included ORF1a harboring 13 mutations followed by ORF1b (6), ORF3a (2), and ORF6 and ORF8 (1 mutation each). Conclusion: BA.2 followed by BA.2.38 was the predominant Omicron lineage circulating in Chhattisgarh. BA.2.75 could supersede other Omicron due to its mutational consortium advantage. The periodical genomic monitoring of Omicron variants is thus required for real-time assessment of circulating strains and their mutational-induced severity.

8.
J Virol Methods ; 312: 114648, 2022 Nov 08.
Статья в английский | MEDLINE | ID: covidwho-2241895

Реферат

In 2020, the novel coronavirus, SARS-CoV-2, caused a pandemic, which is still raging at the time of writing this. Here, we present results from SpikeSeq, the first published Sanger sequencing-based method for the detection of Variants of Concern (VOC) and key mutations, using a 1 kb amplicon from the recognized ARTIC Network primers. The proposed setup relies entirely on materials and methods already in use in diagnostic RT-qPCR labs and on existing commercial infrastructure offering sequencing services. For data analysis, we provide an automated, open source, and browser-based mutation calling software (https://github.com/kblin/covid-spike-classification, https://ssi.biolib.com/covid-spike-classification). We validated the setup on 195 SARS-CoV-2 positive samples, and we were able to profile 85% of RT-qPCR positive samples, where the last 15% largely stemmed from samples with low viral count. We compared the SpikeSeq results to WGS results. SpikeSeq has been used as the primary variant identification tool on > 10.000 SARS-CoV-2 positive clinical samples during 2021. At approximately 4€ per sample in material cost, minimal hands-on time, little data handling, and a short turnaround time, the setup is simple enough to be implemented in any SARS-CoV-2 RT-qPCR diagnostic lab. Our protocol provides results that can be used to choose antibodies in a clinical setting and for the tracking and surveillance of all positive samples for new variants and known ones such as Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1) Delta (B.1.617.2), Omicron BA.1(B.1.1.529), BA.2, BA.4/5, BA.2.75.x, and many more, as of October 2022.

9.
Talanta ; 254: 124127, 2022 Nov 23.
Статья в английский | MEDLINE | ID: covidwho-2241302

Реферат

The Covid-19 variants' transmissibility was further quantitatively analyzed in silico to study the binding strength with ACE-2 and find the binding inhibitors. The molecular interaction energy values of their optimized complex structures (MIFS) demonstrated that Omicron BA.4 and 5's MIFS value (344.6 kcal mol-1) was equivalent to wild-type MIFS (346.1 kcal mol-1), that of Omicron BQ.1 and BQ. 1.1's MIFS value (309.9 and 364.6 kcal mol-1). Furthermore, the MIFS value of Omicron BA.2.75 (515.1 kcal mol-1) was about Delta-plus (511.3 kcal mol-1). The binding strength of Omicron BA.4, BA. 5, and BQ.1.1 may be neglectable, but that of Omicron BA.2.75 was urging. Furthermore, the 79 medicine candidates were analyzed as the binding inhibitors from binding strength with ACE-2. Only carboxy compounds were repulsed from the ACE-2 binding site indicating that further modification of medical treatment candidates may produce an effective binding inhibitor.

10.
Cureus ; 14(11): e31352, 2022 Nov.
Статья в английский | MEDLINE | ID: covidwho-2164194

Реферат

BACKGROUND: The SARS-CoV-2 Omicron variants BA.2.74, BA.2.75, and BA.2.76 have appeared recently in India and have already spread to over 40 countries. They have acquired additional mutations in their spike protein compared to BA.2, branching away on the SARS-CoV-2 phylogenetic tree. These added mutations have raised concerns about the impact on viral pathogenicity, transmissibility, and immune evasion properties of the new variants. MATERIAL AND METHODS: A total of 990 Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) positive SARS-CoV-2 samples, with a cycle threshold value (Ct) less than 25, were processed for SARS-CoV-2 whole genome sequencing between June 3, 2022 to August 7, 2022. All corresponding demographic and clinical data were recorded and analyzed using Microsoft® Excel. RESULTS: Out of 990 samples sequenced, BA.2.75 (23.03%) was the predominant Omicron sublineage, followed by BA.2.38 (21.01%), BA.5 (9.70%), BA.2 (9.09%), BA.2.74 (8.89%) and BA.2.76 (5.56%). A total of 228 cases of BA.2.74, BA.2.75, and BA.2.76 were contacted by telephone, of which 215 (94.30%) were symptomatic with mild symptoms, and 13 (5.70%) had no symptoms. Fever (82.02%) was the most common symptom, followed by cough (49.12%), cold (35.97%), fatigue (27.19%), headache (21.05%), and myalgia (20.61%). Of the 228 cases, 195 (85.53%) cases recovered at home, and 33 (14.47%) required institutional quarantine. Recovery with conservative treatment was observed in 92.98% of cases, while 4.83% required additional oxygen therapy. Only three (1.32%) cases had poor outcomes resulting in death, and the remaining 225 (98.68%) survived. Among the 228 cases, 219 (96.05%) cases were vaccinated with the COVID-19 vaccine; of these, 72.60% had received both doses, 26.03% had also received the precautionary booster dose, while 1.37% were incompletely vaccinated with a single dose of vaccine. CONCLUSION: The current study indicates that the three BA.2 sublineages are causing mild disease in India. However, BA.2.75 has key mutations that are notable for accelerated growth and transmission and require close and effective monitoring.

11.
Cell Rep ; 42(1): 111903, 2023 01 31.
Статья в английский | MEDLINE | ID: covidwho-2158574

Реферат

Variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have caused successive global waves of infection. These variants, with multiple mutations in the spike protein, are thought to facilitate escape from natural and vaccine-induced immunity and often increase in affinity for ACE2. The latest variant to cause concern is BA.2.75, identified in India where it is now the dominant strain, with evidence of wider dissemination. BA.2.75 is derived from BA.2 and contains four additional mutations in the receptor-binding domain (RBD). Here, we perform an antigenic and biophysical characterization of BA.2.75, revealing an interesting balance between humoral evasion and ACE2 receptor affinity. ACE2 affinity for BA.2.75 is increased 9-fold compared with BA.2; there is also evidence of escape of BA.2.75 from immune serum, particularly that induced by Delta infection, which may explain the rapid spread in India, where where there is a high background of Delta infection. ACE2 affinity appears to be prioritized over greater escape.


Тема - темы
COVID-19 , Hepatitis D , Humans , Angiotensin-Converting Enzyme 2 , SARS-CoV-2 , Antibodies
12.
Cell Host Microbe ; 30(11): 1540-1555.e15, 2022 11 09.
Статья в английский | MEDLINE | ID: covidwho-2130372

Реферат

The SARS-CoV-2 Omicron BA.2.75 variant emerged in May 2022. BA.2.75 is a BA.2 descendant but is phylogenetically distinct from BA.5, the currently predominant BA.2 descendant. Here, we show that BA.2.75 has a greater effective reproduction number and different immunogenicity profile than BA.5. We determined the sensitivity of BA.2.75 to vaccinee and convalescent sera as well as a panel of clinically available antiviral drugs and antibodies. Antiviral drugs largely retained potency, but antibody sensitivity varied depending on several key BA.2.75-specific substitutions. The BA.2.75 spike exhibited a profoundly higher affinity for its human receptor, ACE2. Additionally, the fusogenicity, growth efficiency in human alveolar epithelial cells, and intrinsic pathogenicity in hamsters of BA.2.75 were greater than those of BA.2. Our multilevel investigations suggest that BA.2.75 acquired virological properties independent of BA.5, and the potential risk of BA.2.75 to global health is greater than that of BA.5.


Тема - темы
COVID-19 , SARS-CoV-2 , Humans , Antibodies, Neutralizing , Antibodies, Viral , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , COVID-19 Serotherapy
13.
Cell Host Microbe ; 30(11): 1518-1526.e4, 2022 11 09.
Статья в английский | MEDLINE | ID: covidwho-2117599

Реферат

The newly emerged BA.2.75 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant contains 9 additional mutations in its spike (S) protein compared to the ancestral BA.2 variant. Here, we examine the neutralizing antibody escape of BA.2.75 in mRNA-vaccinated and BA.1-infected individuals, as well as the molecular basis underlying functional changes in S. Notably, BA.2.75 exhibits enhanced neutralization resistance over BA.2 but less than the BA.4/5 variant. The G446S and N460K mutations of BA.2.75 are primarily responsible for its enhanced resistance to neutralizing antibodies. The R493Q mutation, a reversion to the prototype sequence, reduces BA.2.75 neutralization resistance. The impact of these mutations is consistent with their locations in common neutralizing antibody epitopes. Further, BA.2.75 shows enhanced cell-cell fusion over BA.2, driven largely by the N460K mutation, which enhances S processing. Structural modeling reveals enhanced receptor contacts introduced by N460K, suggesting a mechanism of potentiated receptor utilization and syncytia formation.


Тема - темы
Antibodies, Neutralizing , COVID-19 , Humans , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Neutralization Tests , Antibodies, Viral , Viral Envelope Proteins
14.
Cell Host Microbe ; 30(11): 1512-1517.e4, 2022 11 09.
Статья в английский | MEDLINE | ID: covidwho-2118001

Реферат

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron subvariant BA.2.75 emerged recently and appears to be spreading. It has nine mutations in spike compared with the currently circulating BA.2, raising concerns that it may further evade vaccine-elicited and therapeutic antibodies. We found BA.2.75 to be moderately more neutralization resistant to sera from vaccinated/boosted individuals than BA.2 (1.8-fold), similar to BA.2.12.1 (1.1-fold), but more neutralization sensitive than BA.4/5 (0.6-fold). Relative to BA.2, BA.2.75 showed heightened resistance to class 1 and class 3 monoclonal antibodies targeting the spike-receptor-binding domain while gaining sensitivity to class 2 antibodies. Resistance was largely conferred by G446S and R460K mutations. BA.2.75 was slightly resistant (3.7-fold) to bebtelovimab, a therapeutic antibody with potent activity against all Omicron subvariants. BA.2.75 also exhibited a higher binding affinity to host receptor ACE2 than other Omicron subvariants. BA.2.75 provides further insight into SARS-CoV-2 evolution as it gains transmissibility while incrementally evading antibody neutralization.


Тема - темы
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , Neutralization Tests , Antibodies, Monoclonal , Antibodies, Viral , Spike Glycoprotein, Coronavirus/genetics , Antibodies, Neutralizing
15.
Drug Resist Updat ; 65: 100882, 2022 Dec.
Статья в английский | MEDLINE | ID: covidwho-2104805

Реферат

WHO-defined SARS-CoV-2 variants of concern (VOC) drive therapeutics and vaccine development. The Omicron VOC is dominating the arena since November 2021, but the number of its sublineages is growing in complexity. Omicron represent a galaxy with a myriad of stars that suddenly rise and expand before collapsing into apparent extinction when a more fit sublineage appears. This has already happened with BA.1, BA.2, and BA.4/5 and is happening with BA.2.75. We review here the current PANGO phylogeny, focusing on sublineages with Spike mutations, and show how frequently xxxxxxxx convergent evolution has occurred in these sublineages. We finally summarize how Omicron evolution has progressively defeated the anti-Spike monoclonal antibodies authorized so far, leaving clinicians to again fall back on COVID19 convalescent plasma from vaccinated donors as the only antibody-based therapy available.


Тема - темы
Antineoplastic Agents, Immunological , COVID-19 , Humans , Antibodies, Monoclonal/genetics , Antibodies, Monoclonal/therapeutic use , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Antibodies, Viral , Antibodies, Neutralizing , COVID-19 Serotherapy
16.
Cell Host Microbe ; 30(11): 1527-1539.e5, 2022 11 09.
Статья в английский | MEDLINE | ID: covidwho-2104544

Реферат

Recently emerged SARS-CoV-2 Omicron subvariant, BA.2.75, displayed a growth advantage over circulating BA.2.38, BA.2.76, and BA.5 in India. However, the underlying mechanisms for enhanced infectivity, especially compared with BA.5, remain unclear. Here, we show that BA.2.75 exhibits substantially higher affinity for host receptor angiotensin-converting enzyme 2 (ACE2) than BA.5 and other variants. Structural analyses of BA.2.75 spike shows its decreased thermostability and increased frequency of the receptor binding domain (RBD) in the "up" conformation under acidic conditions, suggesting enhanced low-pH-endosomal cell entry. Relative to BA.4/BA.5, BA.2.75 exhibits reduced evasion of humoral immunity from BA.1/BA.2 breakthrough-infection convalescent plasma but greater evasion of Delta breakthrough-infection convalescent plasma. BA.5 breakthrough-infection plasma also exhibits weaker neutralization against BA.2.75 than BA.5, mainly due to BA.2.75's distinct neutralizing antibody (NAb) escape pattern. Antibody therapeutics Evusheld and Bebtelovimab remain effective against BA.2.75. These results suggest BA.2.75 may prevail after BA.4/BA.5, and its increased receptor-binding capability could support further immune-evasive mutations.


Тема - темы
COVID-19 , Spike Glycoprotein, Coronavirus , Humans , Spike Glycoprotein, Coronavirus/genetics , SARS-CoV-2 , Antibodies, Neutralizing , Antibodies, Viral , COVID-19 Serotherapy
17.
Infect Drug Resist ; 15: 6317-6330, 2022.
Статья в английский | MEDLINE | ID: covidwho-2098936

Реферат

With over 58 million cases and 6 million deaths by August 2022, the Coronavirus disease 2019 (COVID-19), causing severe acute respiratory syndrome coronavirus 2 (SARs-CoV-2), has had an insurmountable impact on the world's population. This is one of the worst health crises since 1918's influenza pandemic. There are four subvariants of Omicron; BA.1, BA.1.1, BA.2 and BA.3. As a result of new mutations in its spike protein, most of which occur in its receptor binding site, the Omicron variant appears to be more transmissible and less resistant to vaccination and antibody response. Understanding Omicron's virology and mutations is essential to developing diagnostic and therapeutic methods. A thorough assessment of control measures, as well as timely adjustment of control measures, requires addressing such issues as re-infection risk, vaccine response, booster vaccine doses, and the increased rate of Omicron infections. This review article aims to look at the current information about the different types of SARs-CoV-2, focusing on the new subtype BA.2.75.

18.
BioTech (Basel) ; 11(4)2022 Oct 11.
Статья в английский | MEDLINE | ID: covidwho-2071231

Реферат

Omicron BA.2.75 may become the next globally dominant strain of COVID-19 in 2022. The BA.2.75 sub-variant has acquired more mutations (9) in spike protein and other genes of SARS-CoV-2 than any other variant. Thus, its chemical composition and thermodynamic properties have changed compared with earlier variants. In this paper, the Gibbs energy of the binding and antigen-receptor binding rate was reported for the BA.2.75 variant. Gibbs energy of the binding of the Omicron BA.2.75 variant is more negative than that of the competing variants BA.2 and BA.5.

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