Biology subjects

Noureddine, M.

Publications and source records attributed to Noureddine, M..

6 recordsLinked to original sources

bioRxiv2026

Evaluation of new adjuvants in enhancing the immune response to a candidate of Severe Fever with Thrombocytopenia Syndrome Virus vaccine.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging zoonotic disease caused by the tick-borne bunyavirus SFTSV. SFTSV is primarily transmitted by Haemaphysalis longicornis ticks and can cause a hemorrhagic fever-like illness characterized by high fever, thrombocytopenia, leukopenia, and multiorgan failure, with reported case-fatality rates ranging from 10% to over 30%. Despite its growing public health relevance, no licensed vaccines or specific antiviral therapies are currently available. Here, we evaluated a beta-propiolactone-inactivated SFTSV vaccine candidate based on strain YL1, formulated with benchmark adjuvants (Addavax and Alhydrogel) or experimental innate immune agonists, including Sendai virus-derived defective interfering RNA (SDI), a RIG-I agonist, and imidazoquinoline-poly(ethylene glycol)-cholesterol conjugate (IMDQ-P-C), a TLR7/8 agonist, alone or in combination. Using an extended prime-boost regimen, we examined adjuvant-dependent modulation of humoral immunity, antigen-specific cellular recall, antibody cross-reactivity, and functional protection following passive serum transfer and live-virus challenge in IFNAR-/- mice. All adjuvanted formulations induced detectable humoral responses, with Addavax and SDI eliciting the highest virus-specific binding and neutralizing antibody titers. Antigen-specific analyses identified the nucleoprotein (NP) as the dominant target of vaccine-induced immune memory. NP elicited robust antibody response and the broadest cytokine recall profile following ex vivo stimulation. This response was broader than that induced by the whole inactivated virus and was characterized by mixed Th1-associated, Th2-associated, and proinflammatory-associated features that varied across adjuvant formulations. In contrast, the head domain of the Gn glycoprotein elicited limited cellular recall responses, consistent with its relatively weak humoral immunogenicity after both priming and boosting. Nevertheless, sera from SDI and Addavax-adjuvanted groups displayed cross-reactivity with Gn from a heterologous SFTSV strain, suggesting broader antibody recognition across viral genotypes. Functionally, sera from SDI and Addavax-immunized mice conferred partial protection following passive transfer into IFNAR-/- recipients, as reflected by reduced viral loads, delayed disease onset, and prolonged survival after lethal SFTSV challenge. Together, these findings support the immunogenicity and protective potential of a BPL-inactivated SFTSV vaccine platform and identify NP as a major target of vaccine-induced immune memory. They further highlight the importance of adjuvant selection in shaping the magnitude, antigenic focus, and functional quality of vaccine-induced antiviral immunity.

microbiology↗

bioRxiv2025

Disease modulation by TIV vaccination during secondary pneumococcal infections in influenza-infected mice.

Secondary bacterial infections can significantly worsen the clinical course of influenza virus infections and are a leading cause of morbidity and mortality during seasonal influenza epidemics. Despite being a vaccine-preventable disease, influenza-related complications from secondary bacterial infections are an important cause of death, particularly among the elderly population. Streptococcus pneumoniae (Spn) is the most common agent responsible for influenza-related secondary bacterial infections. Influenza virus vaccination serves as an effective prophylactic strategy for preventing influenza and reducing the burden of influenza-associated pathology, including secondary bacterial infection. However, whether the protective effects of influenza virus vaccination differ in the context of a secondary Spn infection at the level of the host response remains poorly characterized. Here, we present a preclinical mouse model to examine the impact of influenza vaccination in scenarios involving single infections with influenza A virus H1N1 (NC99) or Spn serotype 1; simultaneous infection with both NC99 and Spn (coinfection), or NC99 infection followed by Spn infection seven days later (superinfection). A single dose of trivalent inactivated Influenza vaccine (TIV) is able to decrease infection lethality in both secondary bacterial infection scenarios. Protection is associated with reduction in both viral and bacterial titers, decreased production of pro-inflammatory cytokines, protection of alveolar macrophages, prevention of exacerbated lung neutrophil recruitment, modulation of neutrophil activation status and induction of lung eosinophil recruitment and activation. These findings underscore the importance of influenza vaccination in modulating disease progression and preventing morbidity and mortality associated with secondary bacterial infections.

microbiology↗

bioRxiv2025

A combination TLR7/8 and RIG-I agonist adjuvant reverts asthmatic allergic sensitization and prevents aggravated influenza infection in OVA-sensitized mice.

Allergen-specific immunotherapy (AIT) is the only disease-modifying treatment currently available to treat allergy. However, it has limitations, as most allergens are poorly immunogenic, resulting in an AIT process that can take years. Therefore, adjuvant selection becomes critical to achieve a more efficacious therapy. Our group has developed and tested an amphiphilic TLR7/8 agonist (IMDQ) and a RIG-I agonist (SDI) that used alone, or in combination, have demonstrated strong adjuvant activity for influenza and SARS-CoV-2 vaccines in preclinical models. Here we describe the effect of these adjuvants in the sensitization of preclinical models with the ovalbumin (OVA) asthmatic allergic model via an in-depth humoral and cellular immune profiling. We assess their immune skewing and tolerance inducing capacities in previously sensitized preclinical models with different genetic backgrounds (C57BL/6 vs. BALB/c mice). Moreover, we evaluate their effect in an unrelated antigenic challenge with influenza. Finally, we investigate the role of IgG subclasses and T-cell subpopulations in the protection against OVA challenge conferred by the combination of IMDQ and SDI. We demonstrate that OVA-immunization in combination with IMDQ+SDI prevents allergic sensitization via the induction of a balanced Type 1/Type 2 response. Furthermore, it can revert the allergic phenotype in mice previously sensitized with OVA-Alum, through reducing lung eosinophilia, as well as IL-4 and IL-5 production. However, this was dependent on genetic background. IMDQ+SDI sensitization also led to reduced morbidity of a secondary influenza challenge in OVA-sensitized mice. Finally, we demonstrated that IgG2c, by itself, cannot protect from allergic sensitization and that both CD4+ and CD8+ T-cells are needed for IMDQ+SDI prevention of eosinophil recruitment and activation upon intranasal OVA-challenge.

immunology↗

bioRxiv2025

Transient lung eosinophilia during breakthrough influenza infection in vaccinated mice is associated with protective and balanced Type 1/2 immune responses.

Eosinophils are agile cells that participate in a multitude of homeostatic and inflammatory responses in the lung, ranging from allergic asthma to antiviral defense against respiratory viral infection. In the context of vaccination followed by viral infection, such as breakthrough infection, eosinophils have been linked to aberrant Th2 responses like vaccine-enhanced respiratory disease (VAERD). Here, we demonstrate that the lung immune cell composition, cytokine and chemokine repertoire, histopathological profile, and systemic humoral response of breakthrough influenza infection in mice is distinct from that of primary influenza infection or allergic sensitization, canonical Type 1 and 2 immune responses, respectively. Longitudinal comparison of breakthrough infection with allergic sensitization and primary influenza infection demonstrated major differences in lung immunity between treatment groups in female, BALB/c mice. Breakthrough infection mice exhibit lung eosinophil infiltration that peaks at 7-10 days post-challenge, enriched for the Siglec-Fhi subset, but in the absence of overt pro-inflammatory cytokine/chemokine signals, high viral titers, severe lung lesions, goblet cell hyperplasia, allergic levels of total IgE, or enhanced morbidity. Multiparameter fluorescence imaging corroborated findings from flow cytometry and also unveiled interactions between CD101+Siglec-F+ cells with CD3+ cells in the lung tissue space. Imaging also revealed a marked absence of eosinophil or neutrophil extracellular traps in the lungs of breakthrough infection mice, in contrast with allergic sensitization and primary influenza infection, respectively. Altogether, our findings provide a deeper understanding of the kinetics and cell-cell interplay during non-pathological, balanced Type 1/2 immune responses in vaccinated hosts during breakthrough infection.

immunology↗

bioRxiv2024

Dendritic cells type 1 control the formation, maintenance, and function of tertiary lymphoidstructures in cancer

Tertiary lymphoid structures (TLS) are organized immune cell aggregates that arise in chronic inflammatory conditions. In cancer, TLS are associated with better prognosis and enhanced response to immunotherapy, making these structures attractive therapeutic targets. However, the mechanisms regulating TLS formation and maintenance in cancer are incompletely understood. Using spatial transcriptomics and multiplex imaging across various human tumors, we found an enrichment of mature dendritic cells (DC) expressing high levels of CCR7 in TLS, prompting us to investigate the role of DC in the formation and maintenance of TLS in solid tumors. To address this, we developed a novel murine model of non-small cell lung cancer (NSCLC) that forms mature TLS, containing B cell follicles with germinal centers and T cell zones with T follicular helper cells (TFH) and TCF1+PD-1+ progenitor exhausted CD8+ T cells (Tpex). Here we show that, during the early stages of tumor development, TLS formation relies on IFN{gamma}-driven maturation of the conventional DC type 1 (cDC1) subset, their migration to tumor-draining lymph nodes (tdLN), and recruitment of activated T cells to the tumor site. As tumors progress, TLS maintenance becomes independent of T cell egress from tdLN, coinciding with a significant reduction of cDC1 migration to tdLN. Instead, mature cDC1 accumulate within intratumoral CCR7 ligand-enriched stromal hubs. Notably, timed depletion of cDC1 or disruption of their migration to these stromal hubs after TLS are formed alters TLS maintenance. Importantly, we found that cDC1-mediated antigen presentation to both CD4+ and CD8+ T cells and intact CD40 signaling, is critical for the maintenance of TLS, the preservation of the TFH cell pool, the formation of germinal center and the production of tumor-specific IgG antibodies. These findings underscore the key role of mature cDC1 in establishing and maintaining functional TLS within tumor lesions and highlight the potential for cDC1-targeting therapies as a promising strategy to enhance TLS function and improve anti-tumor immunity in patients with cancer.

immunology↗

bioRxiv2019

Structural variation targets neurodevelopmental genes and identifies SHANK2 as a tumor suppressor in neuroblastoma

Neuroblastoma is a malignancy of the developing sympathetic nervous system that accounts for 12% of childhood cancer deaths. Like many childhood cancers, neuroblastoma exhibits a relative paucity of somatic single nucleotide variants (SNVs) and small insertions and deletions (indels) compared to adult cancers. Here, we assessed the contribution of somatic structural variation (SV) in neuroblastoma using a combination of whole genome sequencing (WGS; n=135) and single nucleotide polymorphism (SNP) genotyping (n=914) of matched tumor-normal pairs. Our study design allowed for orthogonal validation and replication across platforms. SV frequency, type, and localization varied significantly among high-risk tumors. MYCN non-amplified high-risk tumors harbored an increased SV burden overall, including a substantial excess of tandem-duplication events across the genome. Genes disrupted by SV breakpoints were enriched in neuronal lineages and autism spectrum disorder (ASD). The postsynaptic adapter protein-coding gene SHANK2, located on chromosome 11q13, was disrupted by SVs in 14% of MYCN non-amplified high-risk tumors based on WGS and 10% in the SNP array cohort. Expression of SHANK2 was low across human-derived neuroblastoma cell lines and high-risk neuroblastoma tumors. Forced expression of SHANK2 in neuroblastoma cell models resulted in significant growth inhibition (P=2.62x10-2 to 3.4x10-5) and accelerated neuronal differentiation following treatment with all-trans retinoic acid (P=3.08x10-13 to 2.38x10-30). These data further define the complex landscape of structural variation in neuroblastoma and suggest that events leading to deregulation of neurodevelopmental processes, such as inactivation of SHANK2, are key mediators of tumorigenesis in this childhood cancer.

cancer biology↗