Biology subjects

Douek, D.

Publications and source records attributed to Douek, D..

6 recordsLinked to original sources

bioRxiv2026

Intranasal Replicating Adenovirus type 4-SARS-CoV-2 Recombinants Induce Superior Immune Response Durability and Efficacy in Preclinical Testing Compared to Standard Intramuscular Vaccines

The portfolio of next generation COVID-19 vaccines would benefit from candidates that induce durable systemic and mucosal immune responses that would lessen person-to-person transmission. We constructed an intranasal (IN) replication-competent adenovirus type 4 recombinant platform to express SARS-CoV-2 Spike variants (Ad4-S) and assessed immunogenicity and efficacy in the Syrian hamster model. Although both IN Ad4-S and intramuscular (IM) vaccines (Ad26.CoV2.S and mRNA-1273) induced serum binding antibodies, only Ad4-S induced a robust mucosal response in the nasal cavity. IN Ad4-S vaccination induced serum neutralizing titers equivalent to or greater than IM vaccination but more durable up to 6 months. Upon challenge, IN immunization also resulted in less weight loss, greater breadth and durability of restriction of viral replication, and less lung pathology than IM immunization up to 268 days after immunization. These data support the potential of the IN Ad4 vaccine platform to reduce transmission of SARS-CoV-2 and other respiratory viruses with pandemic potential.

immunology↗

bioRxiv2024

Multiple full-length homozygous IGH haplotypes from Mauritian cynomolgus macaques

BackgroundNonhuman primates are valuable experimental models for human disease pathology and vaccine design. However, the vast and mostly uncatalogued immunogenomic diversity of typical species adds complexity to the interpretation of experiments and hinders reproducibility. Mauritian cynomolgus macaques (MCM) offer a unique opportunity to circumvent these difficulties, due to their restricted genetic diversity. ResultsWe assembled high-quality immunoglobulin heavy chain (IGH) haplotypes from long-read genomic sequencing of 13 MCM. Four animals were homozygous for IGH, yielding 3 distinct haplotypes, termed H1, H2, and H3. IGH haplotype H1 was observed in two of the homozygotes and 5 additional heterozygous animals, accounting for half of the assemblies recovered. H1 shares only 83% average sequence identity with the IGH locus of the rhesus macaque reference genome, in addition to numerous large structural variations. The other two homozygous haplotypes exhibited considerable variation, including a 60 kilobase (Kbp) deletion and 200 Kbp insertion relative to H1. Furthermore, we annotated the IG gene content from all complete MCM IGH assemblies and found 288 functional IGHV alleles, of which 94 (33%) were not in existing databases. We also identified 68 functional IGHD alleles, 11 functional IGHJ alleles, and 33 functional constant gene alleles across all 5 isotypes. ConclusionsWe identified multiple common and genetically diverse IGH haplotypes within MCM and provide high-quality reference assemblies and annotations for these to facilitate future work with this important animal model.

genomics↗

bioRxiv2022

Breadth of SARS-CoV-2 Neutralization and Protection Induced by a Nanoparticle Vaccine

Coronavirus vaccines that are highly effective against SARS-CoV-2 variants are needed to control the current pandemic. We previously reported a receptor-binding domain (RBD) sortase A-conjugated ferritin nanoparticle (RBD-scNP) vaccine that induced neutralizing antibodies against SARS-CoV-2 and pre-emergent sarbecoviruses and protected monkeys from SARS-CoV-2 WA-1 infection. Here, we demonstrate SARS-CoV-2 RBD-scNP immunization induces potent neutralizing antibodies in non-human primates (NHPs) against all eight SARS-CoV-2 variants tested including the Beta, Delta, and Omicron variants. The Omicron variant was neutralized by RBD-scNP-induced serum antibodies with a mean of 10.6-fold reduction of ID50 titers compared to SARS-CoV-2 D614G. Immunization with RBD-scNPs protected NHPs from SARS-CoV-2 WA-1, Beta, and Delta variant challenge, and protected mice from challenges of SARS-CoV-2 Beta variant and two other heterologous sarbecoviruses. These results demonstrate the ability of RBD-scNPs to induce broad neutralization of SARS-CoV-2 variants and to protect NHPs and mice from multiple different SARS-related viruses. Such a vaccine could provide the needed immunity to slow the spread of and reduce disease caused by SARS-CoV-2 variants such as Delta and Omicron.

immunology↗

bioRxiv2021

Durability of immune responses to the BNT162b2 mRNA vaccine

The development of the highly efficacious mRNA vaccines in less than a year since the emergence of SARS-CoV-2 represents a landmark in vaccinology. However, reports of waning vaccine efficacy, coupled with the emergence of variants of concern that are resistant to antibody neutralization, have raised concerns about the potential lack of durability of immunity to vaccination. We recently reported findings from a comprehensive analysis of innate and adaptive immune responses in 56 healthy volunteers who received two doses of the BNT162b2 vaccination. Here, we analyzed antibody responses to the homologous Wu strain as well as several variants of concern, including the emerging Mu (B.1.621) variant, and T cell responses in a subset of these volunteers at six months (day 210 post-primary vaccination) after the second dose. Our data demonstrate a substantial waning of antibody responses and T cell immunity to SARS-CoV-2 and its variants, at 6 months following the second immunization with the BNT162b2 vaccine. Notably, a significant proportion of vaccinees have neutralizing titers below the detection limit, and suggest a 3rd booster immunization might be warranted to enhance the antibody titers and T cell responses.

immunology↗

bioRxiv2020

Microbiome and Metabolome driven differentiation of TGF-β producing Tregs leads to Senescence and HIV latency

Current therapeutic interventions to eradicate latent HIV ("reservoir") and restore immune function in ART-treated HIV infection have yet to show efficacy. To explore mechanisms of HIV persistence, we apply an integrated systems biology approach and identify a distinct group of individuals with poor CD4 T-cell reconstitution (Immunologic non-responders, "INRs") and high frequencies of cells with inducible HIV. Contrary to the prevailing notion that immune activation drives HIV persistence and immune dysfunction, peripheral blood leukocytes from these subjects have enhanced expression of a network of genes regulated by cellular senescence driving transcription factors (TFs) FOXO3, SMAD2 and IRF3. In these subjects, increased frequencies of regulatory T cells and expression of the TGF-{beta} signaling cascade are complimented by the downregulation of cell cycle, metabolic and pro-inflammatory pathways. Lactobacillaceae family and metabolites (members of the butyrate family - i.e. -ketobutyrate) were correlated with Treg frequencies in "Senescent-INRs" ex vivo, triggered the differentiation of TGF-{beta} producing Tregs and promoted HIV latency establishment in vitro. These cascades, downstream of PD-1/TGF-{beta}, prevent memory T cell differentiation and are associated with an increase in frequencies of cells with inducible HIV ex vivo. Our findings identify cellular senescence responses that can be targeted by PD-1 or TGF-{beta} specific interventions that have shown safety and efficacy in cancer, and may prove to be crucial for HIV eradication.

immunology↗

bioRxiv2020

The identity of human tissue-emigrant CD8+ T cells

Lymphocyte migration is essential for human adaptive immune surveillance. However, our current understanding of this process is rudimentary, because most human studies to date have been restricted to immunological analyses of blood and various tissues. To address this issue, we used an integrated approach to characterize tissue-emigrant immune cells in thoracic duct lymph (TDL). In humans and non-human primates, lymphocytes were by far the most abundant immune lineage population in efferent lymph, and a vast majority of these lymphocytes were T cells. Cytolytic CD8+ T cell subsets were clonotypically discrete and selectively confined to the intravascular circulation, persisting for months after inhibition of S1P-dependent tissue egress by FTY-720. In contrast, non-cytolytic CD8+ T cell subsets with stem-like epigenetic and transcriptional signatures predominated in tissues and TDL. Collectively, these data provide an atlas of the migratory immune system and define the nature of tissue-emigrant CD8+ T cells that recirculate via TDL.

immunology↗