Biology subjects

Sultan, E.

Publications and source records attributed to Sultan, E..

3 recordsLinked to original sources

bioRxiv2025

Repurposed endogenous virus-like vesicles mediate dendritic cell long-range antigen presentation and T cell activation for enhanced cancer vaccination

Dendritic cells (DCs) release extracellular vesicles (DEVs) that amplify antigen presentation while incorporating patient-derived, rapidly evolving antigens. By enriching peptide-MHC and co-stimulatory ligands orders-of-magnitude above donor-cell levels, DEVs emerge as potent vesicle-vaccines, although efficacy remains limited by unclear mechanisms. We show that DCs repurpose viral components to generate endogenous virus-like vesicles (VLVs) that preferentially carry peptide-MHC and high-density co-stimulatory ligands, intensifying and extending antigen presentation. Upon antigen exposure, Arc partners with endogenous envelope proteins to assemble VLVs that directly engage T cells and trigger intrinsic adjuvanticity via viral mimicry. Arc-/- DEVs failed to prime antigen-specific T cell responses, whereas Arc overexpression with its 5'-UTR stem-loop shifted DEVs toward VLVs that trafficked to lymphoid organs, drove rapid CD4-assisted priming and durable CD8-biased memory, suppressed melanoma, and prolonged survival. These reveal a viral-mimicry mechanism enabling long-range immune activation and support Arc+ VLVs as an antigen-agnostic vaccine for cancer immunotherapy. HighlightsO_LIArc+ VLVs intensify and extend DC antigen presentation in vivo C_LIO_LIArc+ VLVs directly engage T cells and trigger viral-mimic adjuvanticity C_LIO_LIArc-/- DEVs fail to prime antigen-specific T cell responses C_LIO_LIEngineered Arc+ VLVs drive durable CD8-biased memory and tumor control C_LIO_LIArc+ VLV vaccination provides long-range and cross-tumor protection in vivo C_LI

bioengineering↗

bioRxiv2025

Gaps and Advances in Long-Term Monitoring of Antarctic Near-Shore and Terrestrial Ecosystems

Environmental change due to greenhouse gas emissions is affecting ecosystems globally; in the polar regions in particular there is already significant evidence of change. The Antarctic Near-Shore and Terrestrial Observation System (ANTOS) aims to establish a cross-continent, cross-national observing network to assess environmental variability and change in the southern polar region. To understand how near-shore and terrestrial Antarctic ecosystems have and will continue to be impacted by anthropogenic environmental changes, a comprehensive review of current long-term monitoring efforts, and two surveys targeting Antarctic researchers, were carried out to evaluate existing monitoring efforts, environmental changes recorded, and to identify areas currently lacking sufficient observations. Results indicate that most data collection is manual and intra-annual, with significant long-term monitoring concentrated in regions with already established infrastructure. The surveys highlight the urgent need for comprehensive coverage of the Antarctics rapidly changing ecosystems using standardized monitoring protocols and increased collaboration. We recommend prioritizing areas experiencing rapid climatic changes and leveraging existing infrastructure to minimize environmental impact of monitoring activities and enhance data comparability across sites.

ecology↗

bioRxiv2025

Explosive cytotoxicity of 'ruptoblasts' bridges hormonal surveillance and immune defense

Current understanding of cytotoxic immunity is shaped by hematopoietic-derived cells - T cells, natural killer cells, and neutrophils. Here, we identify ruptoblasts, a previously unknown cytotoxic glandular cell type in regenerative planarian flatworms. Ruptoblasts undergo an explosive cell death, ruptosis, triggered by activin, a multifunctional hormone that also acts as an inflammatory cytokine. Excessive activin - induced through protein injection, genetic chimerism, or bacterial infection - initiates ruptosis, discharging potent diffusible cytotoxic agents capable of eliminating any nearby cells, bacteria, and even mammalian cells within minutes. Ruptoblast ablation suppresses inflammation but compromises bacterial clearance, highlighting their broad-spectrum immune functions. Mechanistically distinct from known cytotoxic mechanisms, the explosive nature of ruptosis relies on intracellular calcium and dynamic cytoskeletal reorganization. Ruptoblast-like cells appear conserved in diverse basal bilaterians, implying an ancient evolutionary origin. These findings unveil a widespread strategy coupling hormonal regulation with immune defense and expand the landscape of evolutionary immune innovations.

immunology↗