Biology subjects

Theiler, J.

Publications and source records attributed to Theiler, J..

3 recordsLinked to original sources

bioRxiv2021

SARS-CoV-2 variant B.1.1.7 is susceptible to neutralizing antibodies elicited by ancestral Spike vaccines

The SARS-CoV-2 Spike glycoprotein mediates virus entry and is a major target for neutralizing antibodies. All current vaccines are based on the ancestral Spike with the goal of generating a protective neutralizing antibody response. Several novel SARS-CoV-2 variants with multiple Spike mutations have emerged, and their rapid spread and potential for immune escape have raised concerns. One of these variants, first identified in the United Kingdom, B.1.1.7 (also called VUI202012/01), contains eight Spike mutations with potential to impact antibody therapy, vaccine efficacy and risk of reinfection. Here we employed a lentivirus-based pseudovirus assay to show that variant B.1.1.7 remains sensitive to neutralization, albeit at moderately reduced levels (~2-fold), by serum samples from convalescent individuals and recipients of two different vaccines based on ancestral Spike: mRNA-1273 (Moderna), and protein nanoparticle NVX-CoV2373 (Novavax). Some monoclonal antibodies to the receptor binding domain (RBD) of Spike were less effective against the variant while others were largely unaffected. These findings indicate that B.1.1.7 is not a neutralization escape variant that would be a major concern for current vaccines, or for an increased risk of reinfection.

immunology↗

bioRxiv2020

Durable Control of HIV-1 Using a Staphylococcus aureus Cas9-Expressing Lentivirus Co-Targeting Viral Latency and Host Susceptibility

CRISPR/Cas9 gene editing has the potential to revolutionize the clinical management of HIV-1 infection, and may eliminate the need for antiretroviral therapy (ART). Current gene therapies attempt to either excise HIV-1 provirus or target HIV-1 entry receptors to prevent infection of new cells. Using a viral dynamic model, we determined that combining these two interventions, in the presence or absence of ART, significantly lowers the gene editing efficacy thresholds required to achieve an HIV-1 cure. To implement this dual-targeting approach, we engineered a single lentiviral vector that simultaneously targets multiple highly-conserved regions of the provirus and the host CXCR4 coreceptor, and developed a novel coculture system enabling real-time monitoring of latent infection, viral reactivation, and infection of new target cells. Simultaneous dual-targeting depleted HIV-1-infected cells with significantly greater potency than vectors targeting either virus or host independently, highlighting its potential as an HIV-1 cure strategy.

microbiology↗

bioRxiv2020

Spike mutation pipeline reveals the emergence of a more transmissible form of SARS-CoV-2

We have developed an analysis pipeline to facilitate real-time mutation tracking in SARS-CoV-2, focusing initially on the Spike (S) protein because it mediates infection of human cells and is the target of most vaccine strategies and antibody-based therapeutics. To date we have identified thirteen mutations in Spike that are accumulating. Mutations are considered in a broader phylogenetic context, geographically, and over time, to provide an early warning system to reveal mutations that may confer selective advantages in transmission or resistance to interventions. Each one is evaluated for evidence of positive selection, and the implications of the mutation are explored through structural modeling. The mutation Spike D614G is of urgent concern; it began spreading in Europe in early February, and when introduced to new regions it rapidly becomes the dominant form. Also, we present evidence of recombination between locally circulating strains, indicative of multiple strain infections. These finding have important implications for SARS-CoV-2 transmission, pathogenesis and immune interventions.

evolutionary biology↗