Biology subjects

Arien, K. K.

Publications and source records attributed to Arien, K. K..

5 recordsLinked to original sources

bioRxiv2026

Longitudinal Profiling of CD4⁺ T Cell Responses Following de novo Yellow Fever Vaccination

The yellow fever 17D vaccine is one of the most successful live-attenuated viral vaccines, yet the cellular mechanisms underlying its long-term protection remain not fully understood. This study provides a longitudinal analysis of the human CD4+ T cell and IgG response following de novo yellow fever vaccination by focusing. Peripheral blood mononuclear cells (PBMCs) from 49 vaccinated individuals were stimulated with yellow fever (YF) and control peptide pools across four timepoints: pre-vaccination/baseline (D1), day 22 (D22), day 43 (D43), and one year (D365) post-vaccination. Activation-induced marker (AIM) assays confirmed robust activation of CD4+ T cells following yellow fever peptide stimulation, peaking at day 22 post-vaccination and subsequently declining. T-cell receptor (TCR{beta}) sequencing of AIM-sorted CD4+ T cells showed a transient increase in clonal diversity at D22, consistent with broad epitope targeting and early polyclonal expansion. This was followed by repertoire contraction, which could indicate the persistence of a limited set of dominant clonotypes responsible for immune memory formation. TCR repertoires remained largely private over time, indicating a mostly individualized immune response. Next, serological analyses revealed a robust and highly yellow fever virus (YFV)-specific IgG response. Antibody levels peaked within the D22-D43 window and remained elevated at one year post-vaccination. Cross-reactivity toward other flaviviruses was limited, suggesting an antigen-specific humoral response. Together, these findings characterize the longitudinal dynamics of the CD4+ T cell and IgG response following de novo yellow fever vaccination and provide insights into the mechanisms contributing to durable antiviral immunity.

immunology↗

bioRxiv2026

Integrated single-cell analysis reveals interferon-driven immune signatures in a DENV1 human infection model.

Dengue virus infection triggers complex innate and adaptive immune responses, yet the molecular mechanisms that shape early antiviral immunity remain incompletely defined. We performed longitudinal single-cell multi-omics profiling of peripheral blood mononuclear cells from four flavivirus-naive adults experimentally infected with DENV-1, integrating 5' scRNA-seq with paired surface proteomics. Across 95,841 high-quality cells collected at baseline and on days 8 and 10 post-infection, we observed a strong interferon-driven transcriptional response accompanied by marked immune-cell redistribution, including expansion of monocytes and transient reductions in dendritic cells and double-negative T cells. Cytotoxic and helper lymphocyte populations, particularly naive, central memory, and effector memory CD8 T cells, showed extensive crosstalk with monocytes and NK cells, reflecting coordinated cytokine production and cytotoxic activation. Early B cell activation was evident through increased immunoglobulin gene expression. Innate sensing pathways, including RIG-I and Toll-like signaling, were activated across NK, T, and B cell subsets, while also demonstrating enrichment of antigen processing and apoptosis programs. Pro-inflammatory and cytotoxic signatures peaked at day 8, supported by broad upregulation of interferon-stimulated, pro-apoptotic, and regulatory genes. Together, these findings define a robust IFN-driven antiviral state and coordinated activation of immune cell subsets, providing new insights into the immune dynamics of primary dengue infection. ImportanceDengue virus infects millions of people each year, but the early immune events that shape disease outcomes are still unclear. Most studies measure average responses across all blood cells, which hides how individual cell types react. By tracking thousands of single immune cells from volunteers infected with dengue virus under controlled conditions, we show how the immune system rapidly reorganizes during the first days of infection. Many cell types activate antiviral programs, communicate with one another, and shift their behavior in a coordinated way, driven by strong interferon activity. These results provide a clearer view of how early immune responses unfold in humans and identify cellular processes that may influence who develops more severe illness.

microbiology↗

bioRxiv2025

SquiDBase: a community resource of raw nanopore data from microbes

Experimental data-driven research relies on raw data, which consist of unprocessed experimental outputs, whereas derived data are transformed through a number of processing steps to reveal specific insights. Such processing, however, can potentially introduce biases or information loss, compromising transparency and reproducibility. In nucleic acid sequencing, nucleotide sequences stored in the FASTQ format are widely shared, but FASTQ files are generated from platform-specific raw data outputs, which vary depending on the sequencing platform used. The raw data produced by Oxford Nanopore Technologies (ONT) sequencing devices contain valuable biological information and are also useful to improve data processing methods, which includes basecaller optimisation and modification detection. Increasing attention goes to exploring these raw signals to develop algorithms that could improve ONT device portability and enhance target enrichment efficiency through adaptive sampling. Despite these benefits, the storage and sharing of raw nanopore data remain limited due to technical constraints and the lack of appropriate, standardised and centralised infrastructure. To address this challenge, we developed SquiDBase (https://squidbase.org), a dedicated repository to collect raw microbial nanopore sequencing data. To maximise the utility of SquiDBase from its inception, we built SquiDPipe, a Nextflow pipeline for the automated removal of human or unwanted reads from raw nanopore data. Additionally, we sequenced 24 clinically relevant viruses and incorporated them into SquiDBase, significantly expanding the diversity of publicly available reference datasets. By offering a centralised, open-access raw data collection platform, SquiDBase facilitates data sharing, enhances reproducibility, and supports the development and benchmarking of novel computational tools, reinforcing open science in nanopore sequencing research.

bioinformatics↗

bioRxiv2024

Experimental monkeypox virus infection in rats

The global spread of Monkeypox virus (MPXV) clade IIb in 2022/2023 raised concerns about spillback into new animal reservoirs. Experimental inoculation of rats with MPXV resulted in skin lesions and viral shedding in the respiratory tract and skin. These findings suggest a potential role for rats in MPXV transmission.

microbiology↗

bioRxiv2024

Antibodies against medically relevant arthropod-borne viruses in the ubiquitous African rodent Mastomy natalensis

Over the past decades, the number of arthropod-borne virus (arbovirus) outbreaks has increased worldwide. Knowledge regarding the sylvatic cycle (i.e., non-human hosts/environment) of arboviruses is limited, particularly in Africa, and the main hosts for virus maintenance are unknown. Previous studies have shown the presence of antibodies against certain arboviruses (i.e., chikungunya-, dengue- and zika virus) in African non-human primates and bats. We hypothesize that small mammals, specifically rodents, may function as amplifying hosts in anthropogenic environments. The detection of RNA of most arboviruses is complicated by the viruss short viremic period within their hosts. An alternative to determine arbovirus hosts is by detecting antibodies, which can persist several months. We developed a high-throughput multiplex immunoassay to detect antibodies against 15 medically relevant arboviruses. We used this assay to assess almost 1,300 blood samples of the multimammate mouse, Mastomys natalensis from Tanzania. In 24% of the samples, we detected antibodies against at least one of the tested arboviruses, with high seroprevalences of antibodies reacting against dengue virus serotype one (7.6%) and two (8.4%) and chikungunya virus (6%). Seroprevalence was higher in females and increased with age, which could be explained by inherent immunity and behavioral differences between sexes and the increased chance of exposure to an arbovirus with age. We evaluated whether antibodies against multiple arboviruses co-occur more often than randomly and found that this may be true for some members of the Flaviviridae and Togaviridae. In conclusion, the development of an assay against a wide diversity of medically relevant arboviruses enabled the analysis of a large sample collection of one of the most abundant African small mammals. Our findings suggest a role in the transmission of multiple arboviruses by this ubiquitous rodent and provide a solid foundation for future molecular screening to elucidate the role in the arbovirus transmission cycle. Author summaryOne of the main causes of zoonotic related human morbidity and mortality is the transmission of arthropod-borne viruses such as dengue virus, Yellow Fever virus, and chikungunya virus. These viruses cannot only infect humans but also livestock, pets, and wildlife, though our understanding of their non-human hosts remains limited. Rodents are thought to be an interesting host for these viruses because they can be abundant, often live near humans and some are already known to be viral hosts. However, research has focused on non-human primates, neglecting other potential hosts. To address this gap, we have developed a high-throughput antibody test to screen rodent blood against 15 different arboviruses. Our findings reveal that a proportion of Mastomys natalensis, a common African rodent species, carry antibodies that (cross-)react against these viruses. We hypothesize that immunologically naive juveniles may drive transmission, particularly during population outbreaks. These outbreaks coincide with environmental conditions that are favorable for mosquitoes, the vectors of these viruses. Thus, increasing the risk of spillover to humans, livestock, and wildlife. Understanding the role of rodents in arbovirus transmission dynamics is crucial for mitigating zoonotic disease risks.

immunology↗