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Gantner, P.

Publications and source records attributed to Gantner, P..

2 recordsLinked to original sources
bioRxiv2021

Reduced sensitivity of infectious SARS-CoV-2 variant B.1.617.2 to monoclonal antibodies and sera from convalescent and vaccinated individuals

The SARS-CoV-2 B.1.617 lineage emerged in October 2020 in India1-6. It has since then become dominant in some indian regions and further spread to many countries. The lineage includes three main subtypes (B1.617.1, B.1617.2 and B.1.617.3), which harbour diverse Spike mutations in the N-terminal domain (NTD) and the receptor binding domain (RBD) which may increase their immune evasion potential. B.1.617.2 is believed to spread faster than the other versions. Here, we isolated infectious B.1.617.2 from a traveller returning from India. We examined its sensitivity to monoclonal antibodies (mAbs) and to antibodies present in sera from COVID-19 convalescent individuals or vaccine recipients, in comparison to other viral lineages. B.1.617.2 was resistant to neutralization by some anti-NTD and anti-RBD mAbs, including Bamlanivimab, which were impaired in binding to the B.1.617.2 Spike. Sera from convalescent patients collected up to 12 months post symptoms and from Pfizer Comirnaty vaccine recipients were 3 to 6 fold less potent against B.1.617.2, relative to B.1.1.7. Sera from individuals having received one dose of AstraZeneca Vaxzevria barely inhibited B.1.617.2. Thus, B.1.617.2 spread is associated with an escape to antibodies targeting non-RBD and RBD Spike epitopes.

microbiology↗
bioRxiv2021

In-depth single-cell analysis of translation-competent HIV-1 reservoirs identifies cellular sources of plasma viremia

Clonal expansion of HIV-infected cells contributes to the long-term persistence of the HIV reservoir in ART-suppressed individuals. However, the contribution to plasma viremia from cell clones that harbor inducible proviruses is poorly understood. Here, we describe a single-cell approach to simultaneously sequence the TCR, integration sites and proviral genomes from translation-competent reservoir cells, called STIP-Seq. By applying this approach to blood samples from eight participants, we showed that the translation-competent reservoir mainly consists of proviruses with short deletions at the 5-end of the genome, often involving the major splice donor site. TCR and integration site sequencing revealed that antigen-responsive cells can harbor inducible proviruses integrated into cancer-related genes. Furthermore, we found several matches between proviruses retrieved with STIP-Seq and plasma viruses obtained during ART and upon treatment interruption, showing that STIP-Seq can capture clones that are responsible for low-level viremia or viral rebound.

microbiology↗