Escape Mutants Research Articles

Comprehensive genome analysis of hepatitis B virus using nanopore sequencing technology in patients with previously resolved infection and spontaneous reactivation without drug exposure.

A 75-year-old Japanese woman experienced persistent fatigue and progressive jaundice for 6 weeks, and was subsequently diagnosed with acute liver failure. She had not received any immunosuppressive therapies and/or antineoplastic chemotherapy. Blood tests revealed elevated levels of HBsAg, HBV-DNA, and anti-HBc IgG, while anti-HBc IgM was negative. She had undergone hepatitis virus testing 48 weeks earlier, during which HBsAg was negative, indicating that HBV reactivation occurred in a patient with a previously resolved infection, without any drug therapies as triggers, ultimately leading to acute liver failure. Despite receiving multidisciplinary intensive treatment, her condition worsened, resulting in death. Full-length genomic analysis of the HBV strain, performed using nanopore sequencing technology, identified an I126S substitution in HBsAg, known as a vaccine escape mutation, along with a quasispecies consisting primarily of two HBV clone variants: one full-length and the other with a deletion in the nt2,448-nt488 region (sp1 spliced variant). These genetic factors may have contributed to the spontaneous HBV reactivation.

Identification of key antigenic sites in hemagglutinin of H10N3 avian influenza virus

The H10 avian influenza viruses (AIV) have been detected in both birds and mammals. Recently, the cases of human infection with H10N8 and H10N3 in China pose high risk to public health. However, the antigenic sites in hemagglutinin (HA) of H10 are poorly understood. In this study, 3 monoclonal antibodies (MAb), designated as 1F4, 6B3 and 6G12, against the HA protein of the H10N3 strain A/chicken/Taizhou/498/2021(H10N3) (TZ498), were first generated. All of these MAb could effectively inhibit TZ498 in haemagglutination inhibition assay and microneutralization assay. Four novel antigenic sites at positions 135, 208, 227, and 266 (H10 numbering) were identified in the HA of TZ498 through escape mutants selected by these 3 MAb. Moreover, natural mutations at positions 135 and 227 were found in the H10 field strains. All these not only provide novel insights into the molecular markers for monitoring the antigenic variation of H10 but also be helpful for developing efficient control strategies against H10.

An orally available Mpro/TMPRSS2 bispecific inhibitor with potent anti-coronavirus efficacy in vivo.

Coronaviruses have caused three major endemics in the past two decades. Alarmingly, recent identification of novel zoonotic coronaviruses that caused human infections suggests the risk of future coronavirus outbreak caused by spillover infection from animal reservoirs remains high 1,2 . Therefore, development of novel therapeutic options with broad-spectrum anti-coronavirus activities are urgently needed. Here, we develop an orally-available bispecific inhibitor, TMP1, which simultaneously targets key coronavirus replication protease M pro and the essential airway protease TMPRSS2 3,4 . TMP1 shows broad-spectrum protection not only against different SARS-CoV-2 variants but also against multiple human-pathogenic coronaviruses in vitro. By using the K18-hACE2 transgenic mouse, hDPP4 knock-in mouse and golden Syrian hamster models, we demonstrate TMP1 cross-protects against highly-pathogenic coronaviruses (SARS-CoV-1, SARS-CoV-2 and MERS-CoV) in vivo and efficiently abrogates SARS-CoV-2 transmission. Through structural and mutagenesis studies, we confirmed the direct interaction of TMP1 with M pro and TMPRSS2, and pinpoint the key sites of interactions. Importantly, TMP1 inhibits the infection of nirmatrelvir-resistant SARS-CoV-2 escape mutants. Together, our findings demonstrate the antiviral potential of the novel bispecific M pro /TMPRSS2 antiviral design against human-pathogenic coronaviruses and other emerging coronaviruses.

A potent broad-spectrum neutralizing antibody targeting a conserved region of the prefusion RSV F protein

Respiratory syncytial virus (RSV) poses a significant public health challenge, especially among children. Although palivizumab and nirsevimab, neutralizing antibodies (nAbs) targeting the RSV F protein, have been used for prophylaxis, their limitations underscore the need for more effective alternatives. Herein, we present a potent and broad nAb, named 5B11, which exhibits nanogram level of unbiased neutralizing activities against both RSV-A and -B subgroups. Notably, 5B11 shows a ~20-fold increase in neutralizing efficacy compared to 1129 (the murine precursor of palivizumab) and approximately a 3-fold increase in neutralizing efficacy against B18537 in comparison to nirsevimab. Cryo-electron microscopy analysis reveals 5B11’s mechanism of action by targeting a highly conserved epitope within site V, offering a promising strategy with potentially lower risk of escape mutants. Antiviral testing in a female cotton rat model demonstrated that low-dose (1.5 mg/kg) administration of 5B11 achieved comparable prophylactic efficacy to that achieved by high-dose (15 mg/kg) of 1129. Furthermore, the humanized 5B11 showed a superior in vivo antiviral activity against B18537 infection compared to nirsevimab and palivizumab. Therefore, 5B11 is a promising RSV prophylactic candidate applicable to broad prevention of RSV infection.

Identification of Rotavirus Genotypes in Children under Five Years in the United Arab Emirates Using Nanopore Sequencing Technology.

Group A rotaviruses (RVA) remain a principal cause of childhood diarrhea in the UAE, despite universal vaccine use. Monitoring genetic diversity is important for identifying prevalent genotypes and escape mutants. Although real-time polymerase chain reaction (RT-PCR) is widely used for RVA genotyping, it may not detect some new strains. This study evaluates nanopore sequencing and RT-PCR for RVA genotyping. Thirty-three RVA strains from children under 5 years presenting with diarrhea were genotyped using both methods. Thirteen strains were genotyped by RT-PCR and confirmed by nanopore sequencing. Fifteen strains were genotyped by nanopore method alone. Most PCR-genotyped strains (56%) had the VP7 G9 genotype, with G3 in five strains and G12 in two. For VP4, P8 (n = 8) and P4 (n = 7) were dominant. The most frequent combinations were G9P[8] (31%) and G9P[4] (25%). Nanopore sequencing of 28 strains revealed G3P[8] (29%) as the most prevalent, followed by G8P[8] (18%). G9P[8] and G2P[4] were present in 14% of samples with G12P[6] being the rarest (7%). Other combinations were detected in 4% the specimens with one nontypeable. Nanopore sequencing was superior to PCR in identifying diverse and emerging genotypes like G8P[8]. This method may enhance surveillance studies and guide preventive measures for RVA gastroenteritis.

Molecular epidemiology and genetic characterization of hepatitis B virus in two major provinces of Pakistan.

Hepatitis B virus (HBV) infection is a major public health issue and is responsible for considerable morbidity and mortality globally. In Pakistan, the prevalence of chronic HBV infection varies from 2% to 4%, with an estimated exposure rate of approximately 34%. The major objective of this study was to determine the prevalence of HBV genotypes and the pattern of escape mutations in the HBV S gene in two major provinces of Pakistan: Punjab and Khyber Pakhtunkhwa. A total of 146 serum/plasma samples collected from hepatitis B patients were sequenced by the Sanger method. Phylogenetic analysis indicated the intermixed circulation of closely related strains of HBV genotype D and subgenotypes HBV/D1, HBV/D2, and HBV/A2 in both provinces, and various escape mutations (Y100C, P120S/T, G119R, C121S/Y, R122K, T126I, A128V, Q129H/R, G130R, T131N/I, M133T/I, Y134N, C137W, S143L, and D144E) were identified. These findings provide important insights into the current prevalence of HBV genotypes in Pakistan and will help in the establishment of more-efficient disease interventions and patient management strategies.

HBV shows different levels of adaptation to HLA class I-associated selection pressure correlating with markers of replication

Background & AimsImmune responses by CD8 T cells are essential for control of HBV replication. Although selection of escape mutations in CD8 T cell epitopes has been previously described in HBV infection, its overall influence on HBV sequence diversity and correlation with markers of HBV replication remain unclear. MethodsWhole-genome sequencing was applied to HBV isolates from 532 patients with chronic HBV infection and high-resolution HLA class I genotyping. Using a Bayesian model (HAMdetector) for Identification of HLA-associated mutational states (HAMs) the frequency and location of residues under CD8 T cell selection pressure were determined and the levels of adaptation of individual isolates were quantified. ResultsUsing previously published thresholds for the identification of HAMs, a total of 295 residues showed evidence of CD8 T cell escape, the majority of which were located in previously unidentified epitopes. Interestingly, HAMs were highly enriched in the HBV core protein compared to all other proteins. When individual HBV isolates were compared, different levels of adaptation to HLA class I immune pressure were noted. The level of adaptation increased with patient age and correlated with markers of replication, with low levels of adaptation in HBeAg-positive infection. Furthermore, the levels of adaptation negatively correlated with HBV viral load and HBsAg levels, consistent with high levels of HLA class I-associated selection pressure in patients with low replication level. ConclusionsHBV sequence diversity is shaped by HLA class I-associated selection pressure with the HBV core protein being a predominant target of selection. Importantly, different levels of adaptation to immune pressure were observed between HBV infection stages, which need to be considered in the context of T cell-based therapies. Impact and implicationsThe immune response mediated by CD8 T cells plays a critical role in controlling HBV infection and shows promise for therapeutic strategies aimed at achieving a functional cure. This study demonstrates that mutational escape within CD8 T cell epitopes is common in HBV and represents a key factor in the failure of immune control. Notably, the HBV core protein emerges as the primary target of CD8 T cell selection pressure. Additionally, the observed correlation between HBV adaptation levels and viral replication markers indicates that CD8 T cell immunity may influence transitions between phases of chronic HBV infection.

Generative AI in the Advancement of Viral Therapeutics for Predicting and Targeting Immune-Evasive SARS-CoV-2 Mutations.

The emergence of immune-evasive mutations in the SARS-CoV-2 spike protein is consistently challenging existing vaccines and therapies, making precise prediction of their escape potential a critical imperative. Artificial Intelligence(AI) holds great promise for deciphering the intricate language of protein. Here, we employed a Generative Adversarial Network to decipher the hidden escape pathways within the spike protein by generating spikes that closely resemble natural ones. Through comprehensive analysis, we demonstrated that generated sequences capture natural escape characteristics. Moreover, incorporating these sequences into an AI-based escape prediction model significantly enhanced its performance, achieving a 7% increase in detecting natural escape mutations on the experimentally validated Greaney dataset. Similar improvements were observed on other datasets, demonstrating the model's generalizability. Precisely predicting immune-evasive spikes not only enables the design of strategically targeted therapies but also has the potential to expedite future viral therapeutics. This breakthrough carries profound implications for shaping a more resilient future against viral threats.

Advancing CRISPR-Based Solutions for COVID-19 Diagnosis and Therapeutics.

Since the onset of the COVID-19 pandemic, a variety of diagnostic approaches, including RT-qPCR, RAPID, and LFA, have been adopted, with RT-qPCR emerging as the gold standard. However, a significant challenge in COVID-19 diagnostics is the wide range of symptoms presented by patients, necessitating early and accurate diagnosis for effective management. Although RT-qPCR is a precise molecular technique, it is not immune to false-negative results. In contrast, CRISPR-based detection methods for SARS-CoV-2 offer several advantages: they are cost-effective, time-efficient, highly sensitive, and specific, and they do not require sophisticated instruments. These methods also show promise for scalability, enabling diagnostic tests. CRISPR technology can be customized to target any genomic region of interest, making it a versatile tool with applications beyond diagnostics, including therapeutic development. The CRISPR/Cas systems provide precise gene targeting with immense potential for creating next-generation diagnostics and therapeutics. One of the key advantages of CRISPR/Cas-based therapeutics is the ability to perform multiplexing, where different sgRNAs or crRNAs can target multiple sites within the same gene, reducing the likelihood of viral escape mutants. Among the various CRISPR systems, CRISPR/Cas13 and CARVER (Cas13-assisted restriction of viral expression and readout) are particularly promising. These systems can target a broad range of single-stranded RNA viruses, making them suitable for the diagnosis and treatment of various viral diseases, including SARS-CoV-2. However, the efficacy and safety of CRISPR-based therapeutics must be thoroughly evaluated in pre-clinical and clinical settings. While CRISPR biotechnologies have not yet been fully harnessed to control the current COVID-19 pandemic, there is an optimism that the limitations of the CRISPR/Cas system can be overcome soon. This review discusses how CRISPR-based strategies can revolutionize disease diagnosis and therapeutic development, better preparing us for future viral threats.

Characterisation of the antibody-mediated selective pressure driving intra-host evolution of SARS-CoV-2 in prolonged infection.

Neutralising antibodies against the SARS-CoV-2 spike (S) protein are major determinants of protective immunity, though insufficient antibody responses may cause the emergence of escape mutants. We studied the humoral immune response causing intra-host evolution in a B-cell depleted, haemato-oncologic patient experiencing clinically severe, prolonged SARS-CoV-2 infection with a virus of lineage B.1.177.81. Following bamlanivimab treatment at an early stage of infection, the patient developed a bamlanivimab-resistant mutation, S:S494P. After five weeks of apparent genetic stability, the emergence of additional substitutions and deletions within the N-terminal domain (NTD) and the receptor binding domain (RBD) of S was observed. Notably, the composition and frequency of escape mutations changed in a short period with an unprecedented dynamic. The triple mutant S:Delta141-4 E484K S494P became dominant until virus elimination. Routine serology revealed no evidence of an antibody response in the patient. A detailed analysis of the variant-specific immune response by pseudotyped virus neutralisation test, surrogate virus neutralisation test, and immunoglobulin-capture enzyme immunoassay showed that the onset of an IgM-dominated antibody response coincided with the appearance of escape mutations. The formation of neutralising antibodies against S:Delta141-4 E484K S494P correlated with virus elimination. One year later, the patient experienced clinically mild re-infection with Omicron BA.1.18, which was treated with sotrovimab and resulted in an increase in Omicron-reactive antibodies. In conclusion, the onset of an IgM-dominated endogenous immune response in an immunocompromised patient coincided with the appearance of additional mutations in the NTD and RBD of S in a bamlanivimab-resistant virus. Although virus elimination was ultimately achieved, this humoral immune response escaped detection by routine diagnosis and created a situation temporarily favouring the rapid emergence of various antibody escape mutants with known epidemiological relevance.

Exploring the ability of the MD+FoldX method to predict SARS-CoV-2 antibody escape mutations using large-scale data

Antibody escape mutations pose a significant challenge to the effectiveness of vaccines and antibody-based therapies. The ability to predict these escape mutations with computer simulations would allow us to detect threats early and develop effective countermeasures, but a lack of large-scale experimental data has hampered the validation of these calculations. In this study, we evaluate the ability of the MD+FoldX molecular modeling method to predict escape mutations by leveraging a large deep mutational scanning dataset, focusing on the SARS-CoV-2 receptor binding domain. Our results show a positive correlation between predicted and experimental data, indicating that mutations with reduced predicted binding affinity correlate moderately with higher experimental escape fractions. We also demonstrate that higher precision can be achieved using affinity cutoffs tailored to distinct SARS-CoV-2 antibodies from four different classes rather than a one-size-fits-all approach. Further, we suggest that the quartile values of optimized cutoffs reported for each class in this study can serve as a valuable guide for future work on escape mutation predictions. We find that 70% of the systems surpass the 50% precision mark, and demonstrate success in identifying mutations present in significant variants of concern and variants of interest. Despite promising results for some systems, our study highlights the challenges in comparing predicted and experimental values. It also emphasizes the need for new binding affinity methods with improved accuracy that are fast enough to estimate hundreds to thousands of antibody-antigen binding affinities.

Overcoming Bacteriophage Contamination in Bioprocessing: Strategies and Applications.

Bacteriophage contamination has a devastating impact on the viability of bacterial hosts and can significantly reduce the productivity of bioprocesses in biotechnological industries. The consequences range from widespread fermentation failure to substantial economic losses, highlighting the urgent need for effective countermeasures. Conventional prevention methods, which focus primarily on the physical removal of bacteriophages from equipment, bioprocess units, and the environment, have proven ineffective in preventing phage entry and contamination. The coevolutionary dynamics between phages and their bacterial hosts have spurred the development of a diverse repertoire of antiviral defense mechanisms within microbial communities. These naturally occurring defense strategies can be harnessed through genetic engineering to convert phage-sensitive hosts into robust, phage-resistant cell factories, providing a strategic approach to mitigate the threats posed by bacteriophages to industrial bacterial processes. In this review, an overview of the various defense strategies and immune systems that curb the propagation of bacteriophages and highlight their applications in fermentation bioprocesses to combat phage contamination is provided. Additionally, the tactics employed by phages to circumvent these defense strategies are also discussed, as preventing the emergence of phage escape mutants is a key component of effective contamination management.

A new class of capsid-targeting inhibitors that specifically block HIV-1 nuclear import

HIV-1 capsids cross nuclear pore complexes (NPCs) by engaging with the nuclear import machinery. To identify compounds that inhibit HIV-1 nuclear import, we screened drugs in silico on a three-dimensional model of a CA hexamer bound by Transportin-1 (TRN-1). Among hits, compound H27 inhibited HIV-1 with a low micromolar IC50. Unlike other CA-targeting compounds, H27 did not alter CA assembly or disassembly, inhibited nuclear import specifically, and retained antiviral activity against PF74- and Lenacapavir-resistant mutants. The differential sensitivity of divergent primate lentiviral capsids, capsid stability and H27 escape mutants, together with structural analyses, suggest that H27 makes multiple low affinity contacts with assembled capsid. Interaction experiments indicate that H27 may act by preventing CA from engaging with components of the NPC machinery such as TRN-1. H27 exhibited good metabolic stability in vivo and was efficient against different subtypes and circulating recombinant forms from treatment-naïve patients as well as strains resistant to the four main classes of antiretroviral drugs. This work identifies compounds that demonstrate a novel mechanism of action by specifically blocking HIV-1 nuclear import.

Chronic Viral Infections and Hepatic Oncogenesis

Hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis D virus (HDV) are major contrib¬utors to chronic liver disease and hepatocellular carcinoma (HCC) worldwide. Discovered in the 1960s and 1980s, these viruses are associated with significant global health burdens. HBV, a member of the He¬padnaviridae family, is a partially double-stranded DNA virus responsible for chronic liver infections that can lead to HCC. Despite the success of HBV vaccination, challenges such as vaccine escape mutants and non-responders persist. HCV, a member of the Flaviviridae family and a positive-sense single-stranded RNA virus, affects millions globally. While direct-acting antivirals (DAAs) can achieve high rates of viral clearance, vaccine development remains hindered by genetic diversity and immune evasion. HDV, the smallest known human virus, relies on HBV for its propagation. It exacerbates liver disease and increases HCC risk, particularly in co-infected individuals. HDV does not integrate into the host genome, suggesting indirect mechanisms of carcinogenesis, potentially through interactions with HBV. Addressing these chal¬lenges requires enhanced vaccination strategies, improved antiviral therapies, and continued research to understand the complex interplay between these viruses and liver cancer development.

IgG neutralization potential of COVISHIELD™ vaccinated individual’s sera after booster vaccination: Longitudinal and prospective cohort study

The novel SARS-CoV-2 (COVID-19) has caused widespread human turmoil by posing challenges concerning infection prevention, disease diagnosis, and treatment. Several approved vaccines including Sinovac (CoronaVac), COVISHIELD™ (Oxford/AstraZeneca formulation), Janssen (Johnson & Johnson), Sputnik V (Gamaleya), Covaxin (Bharat Biotech), Pfizer (BNT162b2), and others are being used to combat COVID-19. It is crucial to evaluate the kinetics of SARS-CoV-2 antibodies to predict the possibility of reinfection and the longevity of vaccination protection. There is a lack of data on longitudinal humoral antibody dynamics following two and three doses of the SARS-CoV-2 vaccination ChAdOx1-nCOV (COVISHIELDTM) in Indians. Thus, concerns about the efficacy of current vaccines have been raised by a sharp rise in coronavirus disease 2019 (Covid-19) cases caused by sub-variants of SARS-CoV-2 (Severe acute respiratory syndrome corona virus 2) in communities that have received massive vaccinations. The relative immunogenicity and safety of various COVID-19 immunizations administered as a third (booster) dose are not well known. We examined the reactogenicity and immunogenicity of the COVID-19 vaccine as a third dose after two doses of COVISHIELDTM to produce data to optimize the selection of booster vaccinations. After three doses of the COVID-19 vaccine, we evaluated the sera of COVISHIELDTM vaccine recipients for their ability to neutralize the virus. Primary immunization with two doses of COVISHIELDTM vaccine recipients provided significant protection against symptomatic disease caused by the SARS-CoV-2 variants. A COVISHIELDTM vaccine booster vaccine recipient substantially increased protection. The immunization findings showed a significant difference (p ≥ 0.001) between the COVID-19 naive vaccine (n = 438) and the sera of COVID-19-positive recovered subjects (n = 371) who received three doses of COVISHIELDTM. Our findings reveal that anti-RBD antibodies persist over time, which may reduce the probability of reinfection. A three-dose vaccination (n = 53) increases defense against variations by noticeably increasing cross-neutralizing antibody titers. Particularly against variants with antibody escape mutations.

MECHANISMS OF TECOVIRIMAT ANTIVIRAL ACTIVITY AND POXVIRUS RESISTANCE.

Mpox is a zoonotic disease endemic in central and west Africa. However, since 2022, human-adapted mpox virus (MPXV) strains are causing large outbreaks spreading outside these regions, leading the World Health Organization to declare public health emergency twice. Tecovirimat, the most widely used drug to treat these infections, blocks viral egress through a poorly understood mechanism. Tecovirimat-resistant strains, all with mutations in the viral phospholipase F13, pose public health concerns. Herein, we report the structure of an F13 homodimer, both alone and in complex with tecovirimat. We demonstrate that tecovirimat acts as a molecular glue, inducing the dimerization of the phospholipase. F13 escape mutations in MPXV clinical isolates are at the dimer interface and prevent drug-induced dimerization in solution and cells. These findings, which decipher tecovirimat's mode of action, will allow better monitoring of poxvirus outbreaks and pave the way for developing more potent and resilient therapeutics.

Innovation in viruses: fitness valley crossing, neutral landscapes, or just duplications?

Viruses evolve by periods of relative stasis interleaved with sudden, rapid series of mutation fixations, known as evolutionary bursts. These bursts can be triggered by external factors, such as environmental changes, antiviral therapies, or spill-overs from reservoirs into novel host species. However, it has also been suggested that bursts may result from the intrinsic evolutionary dynamics of viruses. Indeed, bursts could be caused by fitness valley crossing, or a neutral exploration of a fitness plateau until an escape mutant is found. In order to investigate the importance of these intrinsic causes of evolutionary bursts, we used a simulation software package to perform massive evolution experiments of viral-like genomes. We tested two conditions: (i) after an external change and (ii) in a constant environment, with the latter condition guaranteeing the absence of an external triggering factor. As expected, an external change was almost systematically followed by an evolutionary burst. However, we also observed bursts in the constant environment as well, albeit much less frequently. We analyzed how many of these bursts are triggered by deleterious, quasi-neutral, or beneficial mutations and show that, while bursts can occasionally be triggered by valley crossing or traveling along neutral ridges, many of them were triggered by chromosomal rearrangements and, in particular, segmental duplications. Our results suggest that combinatorial differences between the different mutation types lead to punctuated evolutionary dynamics, with long periods of stasis occasionally interrupted by short periods of rapid evolution, akin to what is observed in virus evolution.

Isolation and characterization of IgG3 glycan-targeting antibodies with exceptional cross-reactivity for diverse viral families.

Broadly reactive antibodies that target sequence-diverse antigens are of interest for vaccine design and monoclonal antibody therapeutic development because they can protect against multiple strains of a virus and provide a barrier to evolution of escape mutants. Using LIBRA-seq (linking B cell receptor to antigen specificity through sequencing) data for the B cell repertoire of an individual chronically infected with human immunodeficiency virus type 1 (HIV-1), we identified a lineage of IgG3 antibodies predicted to bind to HIV-1 Envelope (Env) and influenza A Hemagglutinin (HA). Two lineage members, antibodies 2526 and 546, were confirmed to bind to a large panel of diverse antigens, including several strains of HIV-1 Env, influenza HA, coronavirus (CoV) spike, hepatitis C virus (HCV) E protein, Nipah virus (NiV) F protein, and Langya virus (LayV) F protein. We found that both antibodies bind to complex glycans on the antigenic surfaces. Antibody 2526 targets the stem region of influenza HA and the N-terminal domain (NTD) region of SARS-CoV-2 spike. A crystal structure of 2526 Fab bound to mannose revealed the presence of a glycan-binding pocket on the light chain. Antibody 2526 cross-reacted with antigens from multiple pathogens and displayed no signs of autoreactivity. These features distinguish antibody 2526 from previously described glycan-reactive antibodies. Further study of this antibody class may aid in the selection and engineering of broadly reactive antibody therapeutics and can inform the development of effective vaccines with exceptional breadth of pathogen coverage.

Identification of antibody-resistant SARS-CoV-2 mutants via N4-Hydroxycytidine mutagenesis

Monoclonal antibodies targeting the Spike protein of SARS-CoV-2 are effective against COVID-19 and might mitigate future pandemics. However, their efficacy is challenged by the emergence of antibody-resistant virus variants. We developed a method to efficiently identify such resistant mutants based on selection from mutagenized virus pools. By inducing mutations with the active compound of Molnupiravir, N4-hydroxycytidine (NHC), and subsequently passaging the virus in the presence of antibodies, we identified specific Spike mutations linked to resistance. Validation of these mutations was conducted using pseudotypes and immunofluorescence analysis. From a Wuhan-like strain of SARS-CoV-2, we identified the following mutations conferring strong resistance towards the corresponding antibodies: Bamlanivimab – E484K, F490S and S494P; Sotrovimab – E340K; Cilgavimab – K444R/E and N450D. From the Omicron B.1.1.529 variant, the strongly selected mutations were: Bebtelovimab – V445A; Sotrovimab – E340K and K356M; Cilgavimab – K444R, V445A and N450D. We also identified escape mutations in the Wuhan-like Spike for the broadly neutralizing antibodies S2K146 – combined G485S and Q493R – and S2H97 – D428G, K462E and S514F. Structural analysis revealed that the selected mutations occurred at antibody-binding residues within the receptor-binding domains of the Spike protein. Most of the selected mutants largely maintained ACE2 binding and infectivity. Notably, many of the identified resistance-conferring mutations are prevalent in real-world SARS-CoV-2 variants, but some of them (G485S, D428G, and K462E) have not yet been observed in circulating strains. Our approach offers a strategy for predicting the therapeutic efficacy of antibodies against emerging virus variants.

Research Progress on the Effects of PI3K/Akt Pathway on Immune Escape

The PI3K/Akt pathway can promote immune escape in tumors, making cancer cells more difficult for the immune system to attack. It is usually possible to regulate the number and function of immune cells by inhibiting apoptosis and T cell activation, and generate immune escape mutations to make cancer cells more resistant to immune monitoring. In-depth understanding of the role of PI3K/Akt pathway in immune escape will help to reveal the mechanism of tumor development, improve the effectiveness of cancer treatment. development, improve the effectiveness of cancer treatment, and restore the immune system's monitoring and attack on cancer cells by inhibiting the activity of PI3K/Akt. In this review, we review the research progress on the effects of G protein-coupled receptor-activated PI3K/Akt pathway on immune escape. This review aims to summarize domestic and international studies that reveal how the PI3K/Akt pathway plays a key role in immune escape, and through in-depth understanding of the role of the PI3K/Akt pathway in immune escape. This review aims to summarize domestic and international studies that reveal how the PI3K/Akt pathway plays a key role in immune escape, and through in-depth understanding of the molecular mechanism, new therapeutic targets can be identified. Scientists from abroad have explored various cancer forms, such as lung, ovarian, and endometrial cancers, etc., so as to provide targeted treatment strategies and increase the applicability of immunotherapy for different cancers; By studying the role of PI3K/Akt pathway, we can explore the potential application of PI3K/Akt pathway for different cancers. By studying the role of PI3K/Akt pathway, we can explore the potential application of existing drugs or new drugs in immunotherapy, so as to improve the diversity of treatment. techniques are combined with clinical data to discover associations between the PI3K/Akt pathway and treatment response in patients to support personalized medicine. Current studies have found that the PI3K/Akt pathway is a key mechanism for immune monitoring of tumor cell escape, and in-depth study of its role is expected to improve the quality of treatment. Current studies have found that the PI3K/Akt pathway is a key mechanism for immune monitoring of tumor cell escape, and in-depth study of its role is expected to improve current immunotherapy strategies and improve patient survival. In the future, whether there are new therapeutic opportunities for PI3K/Akt pathway in immune escape studies, so as to help optimize cancer treatment strategies, improve the efficacy of immunotherapy in future, whether there are new therapeutic opportunities for PI3K/Akt pathway in immune escape studies, so as to help optimize cancer treatment strategies, improve the efficacy of immunotherapy, and improve patient treatment outcomes.