Biology subjects

Brunetti, T.

Publications and source records attributed to Brunetti, T..

6 recordsLinked to original sources

bioRxiv2026

A Candida glabrata adhesin-like effector drives fitness and immunogenicity in the gut

Candida glabrata is a leading cause of invasive candidiasis. The gut serves as its primary reservoir, yet factors governing colonization and pathogenic potential remain poorly defined. Here, we identify immunoglobulin A (IgA) as a key regulator of C. glabrata within the intestinal microbiome. We found that C. glabrata induces an IgA response in a strain-specific manner. Comparative transcriptional and proteomic analyses of IgA-inducing and non-inducing strains identified a putative adhesin, Awp11, whose expression correlated with IgA induction. Awp11 is directly targeted by IgA and is required for inducing C. glabrata-specific IgA and Th17 responses in vivo. Functionally, Awp11 promotes colonization of a complex intestinal microbiome, and intestinal IgA limits this advantage. In most strains, AWP11 transcription is dynamic and limited by IgA in the gut. This identifies Awp11 as a key determinant of strain-dependent immunogenicity and gut colonization that C. glabrata may dynamically regulate to balance colonization and immune evasion.

immunology↗

bioRxiv2024

Deep mutationally scanned (DMS) CHIKV E3/E2 virus library maps viral amino acid preferences and predicts viral escape mutants of neutralizing CHIKV antibodies

As outbreaks of chikungunya virus (CHIKV), a mosquito-borne alphavirus, continue to present public health challenges, additional research is needed to generate protective and safe vaccines and effective therapeutics. Prior research has established a role for antibodies in mediating protection against CHIKV infection, and the early appearance of CHIKV-specific IgG or IgG neutralizing antibodies protects against progression to chronic CHIKV disease in humans. However, the importance of epitope specificity for these protective antibodies and how skewed responses contribute to development of acute and chronic CHIKV-associated joint disease remains poorly understood. Here, we describe the deep mutational scanning of one of the dominant targets of neutralizing antibodies during CHIKV infection, the E3/E2 (also known as p62) glycoprotein complex, to simultaneously test thousands of p62 mutants against selective pressures of interest in a high throughput manner. Characterization of the virus library revealed achievement of high diversity while also selecting out non-functional virus variants. Furthermore, this study provides evidence that this virus library system can comprehensively map sites critical for the neutralization function of antibodies of both known and unknown p62 domain specificities. IMPORTANCEChikungunya virus (CHIKV) is a mosquito-borne alphavirus and re-emerging pathogen of global health concern that causes fever and debilitating acute and chronic joint pain. Prior studies established a critical role for antibodies in protection against CHIKV infection, however, the importance of different antibody epitopes engaged on the virus for these functions is poorly understood. Here, we describe the generation of a high-throughput, functional virus library capable of simultaneously identifying critical neutralization sites for multiple antibodies. We find that, through generation of the virus library, the plasticity of the viral glycoproteins tested varied by subdomains. Additionally, our study revealed new sites in the major CHIKV surface glycoprotein important for neutralization by previously proposed therapeutic monoclonal antibodies. Overall, this study describes a new tool that can be used to better understand antibody responses associated with distinct CHIKV infection outcomes and could contribute to the development of efficacious vaccines and antibody-based therapeutics.

microbiology↗

bioRxiv2024

IL-27 Stablizes Myc-Mediated Transcription In Memory-Fated, Vaccine-Elicited CD8+ T Cells

Protection from pathogens relies on both humoral (antibody-mediated) and cellular (T cell-mediated) responses. While infections robustly elicit both types of immunity, currently approved vaccine adjuvants largely fail to induce T cell responses on par with that instigated by infections. Our goal was to investigate the transcriptional programming that supports the formation of CD8+ T cells elicited by subunit vaccines compared to those elicited by infections. Our data show that vaccine-elicited T cells represent a transcriptionally unique subset of activated T cells with high proliferative capacity and a memory cell fate. This relies on IL-27 signaling, which stabilizes c-Myc and thereby supports the biomass acquisition necessary for clonal expansion. Collectively, our findings reveal that subunit vaccine-elicited T cells uniquely combine aspects of both memory and effector T cell subsets, and selectively utilize IL-27 signaling to sustain the clonal expansion of cells dedicated to a memory fate. One Sentence SummaryIn contrast to infection, subunit vaccines induce a distinct population of CD8+ T cells with memory fate characteristics which maintain their proliferative capacity during the expansion phase through IL-27 receptor signaling.

immunology↗

bioRxiv2024

Vimentin regulates mitochondrial ROS production and inflammatory responses of neutrophils

The intermediate filament vimentin is present in immune cells and is implicated in proinflammatory immune responses. Whether and how it supports antimicrobial activities of neutrophils is not well established. Here, we developed an immortalized neutrophil model to examine the requirement of vimentin. We demonstrate that vimentin restricts the production of proinflammatory cytokines and reactive oxygen species (ROS), but enhances phagocytosis and swarming. We observe that vimentin is dispensable for neutrophil extracellular trap (NET) formation, degranulation, and inflammasome activation. Moreover, gene expression analysis demonstrated that the presence of vimentin was associated with changes in expression of multiple genes required for mitochondrial function and ROS overproduction. Treatment of wild-type cells with rotenone, an inhibitor for complex I of the electron transport chain, increases the ROS levels. Likewise, treatment with mitoTEMPO, a SOD mimetic, rescues the ROS production in cells lacking vimentin. Together, these data show vimentin regulates neutrophil antimicrobial functions and alters ROS levels through regulation of mitochondrial activity.

immunology↗

bioRxiv2023

Unraveling the Phenotypic States of Human innate-like T Cells: Comparative Insights with Conventional T Cells and Mouse Models

The "innate-like" T cell compartment, known as Tinn, represents a diverse group of T cells that straddle the boundary between innate and adaptive immunity, having the ability to mount rapid responses following activation. In mice, this ability is acquired during thymic development. We explored the transcriptional landscape of Tinn compared to conventional T cells (Tconv) in the human thymus and blood using single cell RNA sequencing and flow cytometry. We reveal that in human blood, the majority of Tinn cells, including iNKT, MAIT, and V{delta}2+V{gamma}9+ T cells, share an effector program characterized by the expression of unique chemokine and cytokine receptors, and cytotoxic molecules. This program is driven by specific transcription factors, distinct from those governing Tconv cells. Conversely, only a fraction of thymic Tinn cells displays an effector phenotype, while others share transcriptional features with developing Tconv cells, indicating potential divergent developmental pathways. Unlike the mouse, human Tinn cells do not differentiate into multiple effector subsets but develop a mixed type I/type III effector potential. To conduct a comprehensive cross-species analysis, we constructed a murine Tinn developmental atlas and uncovered additional species-specific distinctions, including the absence of type II Tinn cells in humans, which implies distinct immune regulatory mechanisms across species. The study provides insights into the development and functionality of Tinn cells, emphasizing their role in immune responses and their potential as targets for therapeutic interventions.

immunology↗

bioRxiv2020

Single-cell RNA transcriptomics identifies Hivep3 as essential in regulating the development of innate-like T lymphocytes

Most T lymphocytes leave the thymus as naive cells with limited functionality. However, unique populations of T cells, commonly known as innate-like T cells, differentiate into functionally distinct effector subsets during thymic development under the influence of the transcription factor PLZF. Here, we profiled >10,000 differentiating thymic iNKT cells using single-cell RNA sequencing to provide a comprehensive transcriptional landscape of their maturation, function, and fate decision in steady state. We identified Hivep3, a zinc finger transcription factor and adaptor protein, as a key factor that is expressed in early precursors and regulates the post-selection proliferative burst, differentiation and functions of iNKT cells. Importantly, we extended these results to other PLZF+ innate-like T cell populations, highlighting the unique and common requirement of Hivep3 to the development of all innate-like T cells.

immunology↗