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Sides, M.

Publications and source records attributed to Sides, M..

2 recordsLinked to original sources

Interleukin-17 directly triggers Epstein-Barr virus lytic reactivation in latently infected human B cells

Epstein-Barr virus (EBV) is a ubiquitous human gammaherpesvirus implicated in a wide spectrum of inflammatory and malignant diseases. Although EBV toggles between latent and lytic states, the host cues that control this switch remain incompletely defined. Interleukin-17A (IL-17A; hereafter IL-17), a signature Th17 cytokine, is abundant in EBV-associated tissues, and EBV products can augment IL-17 responses. Whether IL-17 directly modulates the EBV life cycle has remained unknown. Here we show that IL-17 alone is sufficient to induce EBV lytic reactivation in latently infected human B cells. Across RT-qPCR, immunoblotting, and RNA-seq, IL-17 increased the immediate-early regulator BZLF1 (Zta) and upregulated downstream early and late viral genes, consistent with activation of a transcriptome-wide lytic program. Culture supernatants from IL-17-treated cells contained elevated DNase-resistant extracellular EBV DNA, indicating productive replication with encapsidated genomes. Transcriptomic pathway analyses confirmed engagement of IL-17-linked signaling and highlighted inflammatory modules, including NF-{kappa}B and JAK-STAT. Gene Ontology analysis further enriched for regulation of B-cell receptor signaling and B-cell activation, situating IL-17 within B-cell inflammatory circuitry. Together, these findings identify IL-17 as a cytokine cue for EBV lytic entry and provide a mechanistic link between Th17-skewed inflammation and episodic EBV reactivation. This cytokine-driven pathway complements existing models centered on B-cell receptor signaling, hypoxia/HIF-1, COX-2/PGE2, and TGF-{beta} and motivates testing whether modulation of the IL-17/IL-17R axis can alter EBV reactivation in IL-17-rich settings. To our knowledge, this is the first demonstration that IL-17 alone directly triggers EBV lytic reactivation in human cells. IMPORTANCEEpstein-Barr virus (EBV) persists for life by maintaining latency with intermittent lytic reactivation, yet the physiological cues that initiate the latency-lytic switch remain poorly defined. Here we identify the Th17 cytokine interleukin-17A (IL-17) as a direct host trigger of EBV lytic reactivation in latently infected human B cells. IL-17 alone induced the immediate-early transactivator Zta, activated a transcriptome-wide lytic program, and promoted release of DNase-resistant extracellular EBV DNA consistent with encapsidated virions. Transcriptomic analyses confirmed engagement of IL-17-linked inflammatory modules and implicated convergence on signaling nodes shared with canonical B-cell receptor pathways. These findings establish a mechanistic link between Th17-skewed inflammation and EBV reactivation burden, providing a framework to interrogate how IL-17-rich microenvironments influence EBV dissemination and immunopathology and to evaluate whether targeting the IL-17/IL-17R axis can modulate EBV reactivation in disease settings.

microbiology↗

Characterization of Three Variants of SARS-CoV-2 in vivo Shows Host-Dependent Pathogenicity in Hamsters

Animal models are used in preclinical trials to test vaccines, antivirals, monoclonal antibodies, and immunomodulatory drug therapies against SARS-CoV-2. However, these drugs often do not produce equivalent results in human clinical trials. Here, we show how different animal models infected with some of the most clinically relevant SARS-CoV-2 variants, WA1/2020, B.1.617.2/Delta, B.1.1.529/Omicron and BA5.2/Omicron, have independent outcomes. We show that in mice, B.1.617.2 is more pathogenic, followed by WA1, while B.1.1.529 showed an absence of clinical signs. Only B.1.1.529 was able to infect C57BL/6J mice, which lack the human ACE2 receptor. B.1.1.529-infected ACE2 mice had different T cell profiles compared to infected K18-hACE2 mice, while viral shedding profiles and viral titers in lungs were similar between the ACE2 and the C57BL/6J mice. These data suggest B.1.1.529 virus adaptation to a new host and shows that asymptomatic carriers can accumulate and shed virus. Next, we show how B.1.617.2, WA1 and BA5.2/Omicron have similar viral replication kinetics, pathogenicity, and viral shedding profiles in hamsters, demonstrating that the increased pathogenicity of B.1.617.2 observed in mice is host-dependent. Overall, these findings suggest that small animal models are useful to parallel human clinical data, but the experimental design places an important role in interpreting the data. IMPORTANCEThere is a need to investigate SARS-CoV-2 variants phenotypes in different animal models due to the lack of reproducible outcomes when translating experiments to the human population. Our findings highlight the correlation of clinically relevant SARS-CoV-2 variants in animal models with human infections. Experimental design and understanding of correct animal models are essential to interpreting data to develop antivirals, vaccines, and other therapeutic compounds against COVID-19.

microbiology↗