Biology subjects

Halabi, S.

Publications and source records attributed to Halabi, S..

4 recordsLinked to original sources

bioRxiv2026

Community needs for FAIR pathogen data

BackgroundDatasets related to infectious diseases are essential for public health decision-making, yet their reuse remains limited by persistent barriers to data sharing and integration. Achieving data that are Findable, Accessible, Interoperable, and Reusable (FAIR) is widely recognized as essential for accelerating scientific discovery and enabling coordinated responses to emerging threats, but the needs of the global pathogen data community have not been systematically characterized. AimThis study, conducted by the Pathogen Data Network (PDN), aims to identify infrastructural and educational priorities among stakeholders working with infectious disease-related data in order to guide community-responsive support for data sharing and interoperability. MethodsA cross-sectional stakeholder survey was disseminated to a well-defined expert population within PDN networks and via open professional channels. A total of 136 responses from researchers, healthcare professionals, bioinformaticians, and educators were analyzed descriptively to identify prioritized barriers, training needs, and preferred support mechanisms. ResultsRespondents consistently identified structural constraints as the primary impediments to effective data use, including limited funding (74%), data-aggregation challenges (68%), and a shortage of skilled personnel (52%). Respondents identified bioinformatics for infectious disease research (68%) as the highest priority for training, followed by guidance on using the integrated pathogen data and tools portal provided by the PDN, the Pathogens Portal (51%). The Pathogens Portal was also ranked as the most essential PDN resource (72%). Preferred training formats included virtual short courses (68%) and webinars (66%). Notably, while researchers emphasized technical subjects like machine learning, educators prioritized foundational case studies. ConclusionThese findings provide an evidence-based diagnostic of community needs and suggest that barriers to FAIR pathogen data are predominantly systemic rather than purely technological. The survey framework and openly available dataset offer a reusable template for assessing needs in other communities and regions. By aligning training, infrastructure development, and outreach with empirically identified priorities, organizations supporting infectious disease research can strengthen the interoperability and reuse of data and establish a benchmark for future community-driven improvements.

scientific communication and education↗

bioRxiv2026

Simplifying principles that underlie the highly complex peptide motif of the promiscuous chicken class I molecule, BF2*21:01

In chickens and humans, classical class I molecules of the major histocompatibility complex (MHC) have a spectrum of correlated properties, including cell surface expression and peptide repertoire. Understanding the impact of these promiscuous generalists and fastidious specialists is of considerable interest. The promiscuous BF2 molecule from the chicken B21 haplotype, BF2*21:01, binds a wide range of peptides by remodelling the peptide-binding site, allowing co-variation of the anchor residues at peptide positions P2 and Pc-2, and binding of an anchor residue at Pc. Using in vitro refolding assays with peptides and peptide libraries, determining thermostability and crystal structures, and analysing a chicken B21 cell line by immunopeptidomics, we found that BF2*21:01 will accommodate many possible combinations at P2 and Pc-2, as well as several hydrophobic amino acids at Pc. However, marked preferences for particular peptide lengths, particular amino acids at the three anchor residues, and particular combinations of amino acids at P2 and Pc-2 as well as at P3 and Pc-3 together lead to high frequencies of major peptides while still allowing the possibility of presenting a wide peptide repertoire. These simplifying principles may eventually allow predictions of pathogen peptides with stable binding for this iconic promiscuous class I molecule, as well as providing the data for more sophisticated peptide prediction methods.

immunology↗

bioRxiv2025

A major histocompatibility complex (MHC) class II molecule that binds the same viral pathogen peptide with both nonamer and decamer core sequences for presentation to T cells

Classical molecules encoded by the major histocompatibility complex (MHC) are central to immune responses. Compared to typical mammals, the chicken MHC is small and simple, determining life or death from economically-important pathogens like avian influenza virus and Mareks disease virus (MDV). Several genes within the tightly-linked chicken MHC have been suggested to determine resistance and susceptibility to MDV, but it was a surprise to find that the dominantly-expressed class II molecule from the resistant B2 haplotype employed a novel peptide-binding mode with a decamer core sequence compared to the susceptible B19 haplotype with a typical nonamer core. We examined the crystal structure of the dominantly-expressed class II molecule from another resistant haplotype, B21, which is extremely frequent in commercial chicken flocks, to find that it bound the same MDV peptide with both nonamer and decamer cores, revealing an unexpected plasticity of binding that potentially increases the immune response to this devastating pathogen.

immunology↗

bioRxiv2020

Differential host response to a herpesvirus: Mareks disease virus peptides on chicken MHC class II molecules are derived from only a few genes and illustrate a new mode of peptide binding

Viral diseases pose major threats to humans and other animals, including the billions of chickens that are an important food source as well as a public health concern due to zoonotic pathogens. Unlike humans and other typical mammals, the major histocompatibility complex (MHC) of chickens can confer decisive resistance or susceptibility to many viral diseases. An iconic example is Mareks disease, caused by an oncogenic herpesvirus with over 100 genes. Classical MHC class I and class II molecules present antigenic peptides to T lymphocytes, and it has been hard to understand how such MHC molecules could be involved in susceptibility to Mareks disease, given the potential number of peptides from over 100 genes. We used a new in vitro infection system and immunopeptidomics to determine peptide motifs for the two class II molecules expressed by the MHC haplotype B2, which is known to confer resistance to Mareks disease. Surprisingly, we found that the vast majority of viral peptide epitopes presented by chicken class II molecules arise from only four viral genes, nearly all having the peptide motif for BL2, the dominantly-expressed class II molecule in chickens. We expressed BL2 linked to several MDV peptides, and determined one X-ray crystal structure, showing how a single small amino acid in the binding site causes a crinkle in the peptide, leading to core binding peptide of ten amino acids, compared to the nine amino acids in all other reported class II molecules. The limited number of potential T cell epitopes from such a complex virus can explain the differential MHC-determined resistance to MDV, but raises questions of mechanism and opportunities for vaccine targets in this important food species, as well as providing a basis for understanding class II molecules in other species including humans.

immunology↗