Biology subjects

Souque, P.

Publications and source records attributed to Souque, P..

2 recordsLinked to original sources

bioRxiv2020

Intranasal Immunization with a Lentiviral Vector Coding for SARS-CoV-2 Spike Protein Confers Vigorous Protection in Pre-Clinical Animal Models

To develop a vaccine candidate against COVID-19, we generated a Lentiviral Vector (LV), eliciting neutralizing antibodies against the Spike glycoprotein of SARS-CoV-2. Systemic vaccination by this vector in mice, in which the expression of the SARS-CoV-2 receptor hACE2 has been induced by transduction of respiratory tract cells by an adenoviral vector, conferred only partial protection, despite an intense serum neutralizing activity. However, targeting the immune response to the respiratory tract through an intranasal boost with this LV resulted in > 3 log10 decrease in the lung viral loads and avoided local inflammation. Moreover, both integrative and non-integrative LV platforms displayed a strong vaccine efficacy and inhibited lung deleterious injury in golden hamsters, which are naturally permissive to SARS-CoV-2 replication and restitute the human COVID-19 physiopathology. Our results provide evidence of marked prophylactic effects of the LV-based vaccination against SARS-CoV-2 and designate the intranasal immunization as a powerful approach against COVID-19. HighlightsA lentiviral vector encoding for Spike predicts a promising COVID-19 vaccine Targeting the immune response to the upper respiratory tract is key to protection Intranasal vaccination induces protective mucosal immunity against SARS-CoV-2 Lung anti-Spike IgA responses correlate with protection and reduced inflammation

immunology↗

bioRxiv2020

Clustering and reverse transcription of HIV-1 genomes in nuclear niches of macrophages

In order to replicate, the Human Immunodeficiency Virus (HIV-1) reverse transcribes its RNA genome into DNA, which subsequently integrates into host cell chromosomes. These two key events of the viral life cycle are commonly viewed as separate not only in time but also in cellular space, since reverse transcription (RT) is thought to be completed in the cytoplasm before nuclear import and integration. However, the spatiotemporal organization of the early replication cycle in macrophages, natural non-dividing target cells that constitute reservoirs of HIV-1 and an obstacle to curing AIDS, remains unclear. Here, we demonstrate that infected macrophages display large nuclear foci of viral DNA and viral RNA, in which multiple genomes cluster together. These clusters form in the absence of chromosomal integration, sequester the paraspeckle protein CPSF6 and localize to nuclear speckles. Strikingly, we show that viral RNA clusters consist mostly of genomic, incoming RNA, both in cells where RT is pharmacologically suppressed and in untreated cells. We demonstrate that, after temporary inhibition, RT can resume in the nucleus and lead to vDNA accumulation in these clusters. We further show that nuclear RT can result in transcription competent viral DNA. These findings change our understanding of the early HIV-1 replication cycle, and may have implications for understanding HIV-1 persistence.

microbiology↗