Biology subjects

Vanshylla, K.

Publications and source records attributed to Vanshylla, K..

9 recordsLinked to original sources

bioRxiv2023

Dissecting the impact of somatic hypermutation on SARS-CoV-2 neutralization and viral escape

Somatic hypermutation (SHM) drives affinity maturation and continues over months in SARS-CoV-2 neutralizing antibodies. Yet, several potent SARS-CoV-2 antibodies carry no or only few mutations, leaving the question of how ongoing SHM affects neutralization. Here, we reverted variable region mutations of 92 antibodies and tested their impact on SARS-CoV-2 binding and neutralization. Reverting higher numbers of mutations correlated with decreasing antibody functionality. However, some antibodies, including the public clonotype VH1-58, remained unaffected for Wu01 activity. Moreover, while mutations were dispensable for Wu01-induced VH1-58 antibodies to neutralize Alpha, Beta, and Delta variants, they were critical to neutralize Omicron BA.1/BA.2. Notably, we exploited this knowledge to convert the clinical antibody tixagevimab into a BA.1/BA.2-neutralizer. These findings substantially broaden our understanding of SHM as a mechanism that not only improves antibody responses during affinity maturation, but also counteracts antigenic imprinting through antibody diversification and thus increases the chances of neutralizing viral escape variants.

immunology↗

bioRxiv2022

Neutralization sensitivity of the SARS-CoV-2 Omicron BA.2.75 sublineage

The recently emerged BA.2.75 Omicron sublineage of SARS-CoV-2 identified in numerous countries is rapidly increasing in prevalence in regions of India. Compared with BA.2, the spike protein of BA.2.75 differs in nine amino acid residues. To determine the impact of the spike mutations on polyclonal and monoclonal antibody activity, we investigated the neutralization sensitivity of BA.2.75 in comparison with B.1, BA.2, BA.2.12.1, and BA.4/5. Analysis of post-boost samples from 30 vaccinated individuals revealed significantly lower serum neutralizing activity against BA.2.75 than against BA.2. However, BA.2.75 was more sensitive to serum neutralization than the widely circulating BA.4/5 sublineages. Moreover, evaluation of 17 clinical-stage monoclonal antibodies demonstrated individual differences in Omicron sublineage activity. Notably, some authorized antibodies with low activity against other Omicron sublineages demonstrated high BA.2.75 neutralizing potency. Our results indicate a less pronounced degree of antibody evasion of BA.2.75 compared with BA.4/5 and suggest that factors beyond immune evasion may be required for an expansion of BA.2.75 over BA.4/5.

immunology↗

bioRxiv2022

Delineating antibody escape from Omicron variants

SARS-CoV-2 neutralizing antibodies play a critical role in prevention and treatment of COVID-19 but are challenged by viral evolution and antibody evasion, exemplified by the highly resistant Omicron BA.1 sublineage.1-12 Importantly, the recently identified Omicron sublineages BA.2.12.1 and BA.4/5 with differing spike mutations are rapidly emerging in various countries. By determining polyclonal serum activity of 50 convalescent or vaccinated individuals against BA.1, BA.1.1, BA.2, BA.2.12.1, and BA.4/5, we reveal a further reduction of BA.4/5 susceptibility to vaccinee sera. Most notably, delineation of the sensitivity to an extended panel of 163 antibodies demonstrates pronounced antigenic differences of individual sublineages with distinct escape patterns and increased antibody resistance of BA.4/5 compared to the most prevalent BA.2 sublineage. These results suggest that the antigenic distance from BA.1 and the increased resistance compared to BA.2 may favor immune escape-mediated expansion of BA.4/5 after the first Omicron wave. Finally, while most monoclonal antibodies in clinical stages are inactive against all Omicron sublineages, we identify promising novel antibodies with high pan-Omicron neutralizing potency. Our study provides a detailed understanding of the antibody escape from the most recently emerging Omicron sublineages that can inform on effective strategies to prevent and treat COVID-19.

immunology↗

bioRxiv2021

No substantial pre-existing B cell immunity against SARS-CoV-2 in healthy adults

Pre-existing immunity against SARS-CoV-2 may have critical implications for our understanding of COVID-19 susceptibility and severity. Various studies recently provided evidence of pre-existing T cell immunity against SARS-CoV-2 in unexposed individuals. In contrast, the presence and clinical relevance of a pre-existing B cell immunity remains to be fully elucidated. Here, we provide a detailed analysis of the B cell response to SARS-CoV-2 in unexposed individuals. To this end, we extensively investigated the memory B cell response to SARS-CoV-2 in 150 adults sampled pre-pandemically. Comprehensive screening of donor plasma and purified IgG samples for binding and neutralization in various functional assays revealed no substantial activity against SARS-CoV-2 but broad reactivity to endemic betacoronaviruses. Moreover, we analyzed antibody sequences of 8,174 putatively SARS-CoV-2-reactive B cells on a single cell level and generated and tested 158 monoclonal antibodies. None of the isolated antibodies displayed relevant binding or neutralizing activity against SARS-CoV-2. Taken together, our results show no evidence of relevant pre-existing antibody and B cell immunity against SARS-CoV-2 in unexposed adults.

immunology↗

bioRxiv2021

Intranasal administration of a monoclonal neutralizing antibody protects mice against SARS-CoV-2 infection

Despite recent availability of vaccines against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), there is an urgent need for specific anti-SARS-CoV-2 drugs. Monoclonal neutralizing antibodies are an important drug class in the global fight against the SARS-CoV-2 pandemic due to their ability to convey immediate protection and their potential to be used as both, prophylactic and therapeutic drugs. Clinically used neutralizing antibodies against respiratory viruses are currently injected intravenously, which can lead to suboptimal pulmonary bioavailability and thus to a lower effectiveness. Here we describe DZIF-10c, a fully human monoclonal neutralizing antibody that binds the receptor-binding domain of SARS-CoV-2 spike protein. DZIF-10c displays an exceptionally high neutralizing potency against SARS-CoV-2 and retains activity against the variants of concern B.1.1.7 and B.1.351. Importantly, not only systemic but also intranasal application of DZIF-10c abolished presence of infectious particles in the lungs of SARS-CoV-2 infected mice and mitigated lung pathology. Along with a favorable pharmacokinetic profile, these results highlight DZIF-10c as a novel human SARS-CoV-2 neutralizing antibody with high in vitro and in vivo antiviral potency. The successful intranasal application of DZIF-10c paves the way for clinical trials investigating topical delivery of anti-SARS-CoV-2 antibodies. Significance StatementMonoclonal neutralizing antibodies are important in the global fight against the SARS-CoV-2 pandemic due to their ability to convey immediate protection. However, their intravenous application might lead to suboptimal bioavailability in the lung. We here precisely characterize a new monoclonal neutralizing antibody (DZIF-10c) that binds to the receptor binding domain of the spike protein of SARS-CoV-2. DZIF-10c neutralizes SARS-CoV-2 with exceptionally high potency and maintains activity against circulating variants of concern. The antibody has a favorable pharmacokinetic profile and protects mice from SARS-CoV-2 infection. Importantly, we show that intranasal administration of DZIF-10c generates protective efficacy. These results not only identify DZIF-10c as a novel highly potent neutralizing antibody, but further pave the way for a topical application of anti-SARS-CoV-2 antibodies.

microbiology↗

bioRxiv2021

Kinetics and correlates of the neutralizing antibody response to SARS-CoV-2

A detailed understanding of antibody-based SARS-CoV-2 immunity has critical implications for overcoming the COVID-19 pandemic and for informing on vaccination strategies. In this study, we evaluated the dynamics of the SARS-CoV-2 antibody response in a cohort of 963 recovered individuals over a period of 10 months. Investigating a total of 2,146 samples, we detected an initial SARS-CoV-2 antibody response in 94.4% of individuals, with 82% and 79% exhibiting serum and IgG neutralization, respectively. Approximately 3% of recovered patients demonstrated exceptional SARS-CoV-2 neutralizing activity, defining them as elite neutralizers. These individuals also possessed effective cross-neutralizing IgG antibodies to SARS-CoV-1 without any known prior exposure to this virus. By applying multivariate statistical modeling, we found that sero-reactivity, age, time since disease onset, and fever are key factors predicting SARS-CoV-2 neutralizing activity in mild courses of COVID-19. Investigating longevity of the antibody response, we detected loss of anti-spike reactivity in 13% of individuals 10 months after infection. Moreover, neutralizing activity had an initial half-life of 6.7 weeks in serum versus 30.8 weeks in purified IgG samples indicating the presence of a more stable and long-term memory IgG B cell repertoire in the majority of individuals recovered from COVID-19. Our results demonstrate a broad spectrum of the initial SARS-CoV-2 neutralizing antibody response depending on clinical characteristics, with antibodies being maintained in the majority of individuals for the first 10 months after mild course of COVID-19.

immunology↗

bioRxiv2020

A novel humanized mouse model to study mucosal HIV-1 transmission and prevention

Humanized mice have been critical for HIV-1 research, but are inefficient at mucosal HIV-1 transmission. We present a fetal tissue-independent model called CD34T+ with enhanced human leukocyte levels in the blood and improved T cell homing to the gut-associated lymphoid tissue. CD34T+ mice are highly permissive to intra-rectal HIV-1 infection, which can be prevented by infusion of broadly neutralizing antibodies. Therefore, CD34T+ mice provide a novel platform for mucosal HIV-1 transmission and prevention studies.

immunology↗

bioRxiv2020

Predicting in vivo escape dynamics of HIV-1 from a broadly neutralizing antibody

Broadly neutralizing antibodies are promising candidates for treatment and prevention of HIV-1 infections. Such antibodies can temporarily suppress viral load in infected individuals; however, the virus often rebounds by escape mutants that have evolved resistance. In this paper, we map an in vivo fitness landscape of HIV-1 interacting with broadly neutralizing antibodies, using data from a recent clinical trial. We identify two fitness factors, antibody dosage and viral load, that determine viral reproduction rates reproducibly across different hosts. The model successfully predicts the escape dynamics of HIV-1 in the course of an antibody treatment, including a characteristic frequency turnover between sensitive and resistant strains. This turnover is governed by a dosage-dependent fitness ranking, resulting from an evolutionary tradeoff between antibody resistance and its collateral cost in drug-free growth. Our analysis suggests resistance-cost tradeoff curves as a measure of antibody performance in the presence of resistance evolution.

biophysics↗

bioRxiv2020

Longitudinal isolation of potent near-germline SARS-CoV-2-neutralizing antibodies from COVID-19 patients

The SARS-CoV-2 pandemic has unprecedented implications for public health, social life, and world economy. Since approved drugs and vaccines are not available, new options for COVID-19 treatment and prevention are highly demanded. To identify SARS-CoV-2 neutralizing antibodies, we analysed the antibody response of 12 COVID-19 patients from 8 to 69 days post diagnosis. By screening 4,313 SARS-CoV-2-reactive B cells, we isolated 255 antibodies from different time points as early as 8 days post diagnosis. Among these, 28 potently neutralized authentic SARS-CoV-2 (IC100 as low as 0.04 g/ml), showing a broad spectrum of V genes and low levels of somatic mutations. Interestingly, potential precursors were identified in naive B cell repertoires from 48 healthy individuals that were sampled before the COVID-19 pandemic. Our results demonstrate that SARS-CoV-2 neutralizing antibodies are readily generated from a diverse pool of precursors, fostering the hope of rapid induction of a protective immune response upon vaccination.

immunology↗