Immunogenetics

T cell repertoire sequencing has unveiled a vast, complex array of T cells responsible for the human immune responses. Traditional analytic methodology fails to fully characterize and quantify the diversity of T cell receptors constituting the T cell repertoire. T cell receptor clonal frequency measured in terms of T cell receptor beta (TRB) V gene segment usage when arrayed in correspondence with the respective V gene segment positions on the TRB loci yields a periodic, undulating curve in the spatial domain of the TRB genomic locus. Using the genomic distance from the TRB-D1 segment to the TRB-V1-29 segments, Fourier analysis was performed utilizing Lomb-Scargle periodogram to obtain Spectral Power curves quantifying the TRB V clonal frequencies from 6 allogeneic stem cell transplant donors (baseline) and recipients (>/=100 days) using a variety of analytic software. Spectral Power curves revealed dominant spectral peaks at wavelengths ranging from 4-9 kb (113-252 millicycles/kb) in the six donors, with consistent frequency domain spectral patterns. This is consistent with similar use of V segments across healthy individuals. Recipients on the other hand demonstrated more dispersed spectra, with a spectral centroid shifted towards higher frequencies compared to donors (260 vs. 247 millicycles/kb). Consistent with this observation, the Low Frequency Index was lower in the recipients (0.18 vs 0.20). Power was concentrated in the <3 kb and 3-12 kb wavelengths in both groups. The analyses reported here demonstrate that the healthy SCT donors have a remarkably similar spectral signature occupying short to intermediate wavelegnths in the frequency domain, whereas recipients tend to shift towards higher frequencies. These findings are consistent with a normal organized distribution of TRB V segment usage in healthy individuals (by analogy other loci), and a more diffuse and disorderly usage in recipients, consistent with the notion of T cell responses constituting a dynamical system which evolves as a function of time. Fourier analysis of TRB (and potentially TRA) sequencing data provides a repertoire wide summary of T cell clonal distribution.

Variant intolerance methods score the essentiality of genes based on large datasets of genetic variants and have been used in population genomics of humans and model organisms. In this paper, we estimated Residual Variation Intolerance Scores for protein-coding genes and predicted protein domains in cattle. In agreement with results from other species, the most variant-tolerant genes and domains included genes related to olfaction and adaptive immunity, whereas the least-variant tolerant genes and domains included genes involved in fundamental cellular processes. There was a moderate positive correlation with estimates from orthologous human genes. We provide estimates of variant intolerance for cattle may be useful for genomic analyses of deleterious variants and population genomics in cattle.

Advances in immunophenotyping of tumour-infiltrating lymphocytes (TILs) have improved our understanding of prognostic biomarkers and immune targets in human melanoma. However, whether the tumour-immune landscape in canine oral malignant melanoma (COMM) is concordant with that of human melanoma has not been properly defined. To address this gap, we developed a 16-colour spectral flow cytometry panel to characterise TIL phenotypic and functional profiles in COMM. Validation using mitogen-stimulated peripheral blood mononuclear cells from healthy dogs (n = 5) demonstrated robust identification of major T cell lineages, including regulatory T cells (Tregs) and memory subsets, and reliable evaluation of their activation and exhaustion status. COMM patients (n = 8) displayed a distinct protumour microenvironment, characterised by an increased proportion of Tregs, enrichment of tumour-specific exhausted-like T cells co-expressing programmed cell death protein 1 (PD-1) and tumour necrosis factor receptor 2 (TNFR2), and a reduction in cytotoxic CD8 and natural killer T (NKT) cell populations compared with tissue-resident (n = 4) and circulating (n = 8) lymphocytes. Analysis of additional solid tumours, including a mast cell tumour, nerve sheath tumour and adrenal cortical carcinoma, further supported the capability of the panel to identify similar patterns of immune dysregulation across diverse canine tumour landscapes. Collectively, this work describes the first detailed evaluation of canine TIL immunophenotyping using spectral flow cytometry and provides insights into the immunosuppressive mechanisms shaping the tumour microenvironment in COMM. These findings not only increase our understanding of canine tumour immunology but also identify potential immune targets and support ongoing comparative immuno-oncology efforts.

Acute myeloid leukemia (AML) is an aggressive hematologic malignancy associated with a poor prognosis and an unmet need for more effective treatment options, particularly after relapse. One potential approach to address this need, which has been used successfully in solid tumors, is adoptive transfer of T cells engineered to express specific T cell receptors (TCRs). Particularly attractive are TCRs that can target epitopes derived from oncogenes on which cancer cells depend while sparing normal cells that do not harbor the mutation. One promising oncogenic target in AML is mutated nucleophosmin 1 (mtNPM1), present in up to 30% of AML cases. Most NPM1 mutations result in a common frameshifted sequence that generates peptides presented by several class I human leukocyte antigens (HLAs), such as HLA-A*11:01. In this study, we vaccinated HLA-A*11:01-transgenic mice with the mtNPM1 peptide AVEEVSLRK and isolated six functional TCRs from mtNPM1-reactive lymphocytes. When engineered into human T cells, two of these TCRs consistently mediated robust and specific lysis of an AML cell line and primary AML cells co-expressing HLA-A*11:01 and mtNPM1. Neither TCR recognized related human peptides, HLA-A*11:01-expressing normal peripheral blood mononuclear cells or stem/progenitor cells, or cells expressing diverse allogeneic HLAs, suggesting a low risk of cross-reactivity and alloreactivity. In an AML xenograft model, both TCRs controlled AML in hematopoietic organs, although extramedullary tumors emerged during treatment, potentially reflecting the aggressive behavior of the model that may not be representative of AML in patients. Together, these data suggest that the two TCRs represent strong candidates for further preclinical development in adoptive T cell therapy for NPM1-mutated, HLA-A*11:01-positive AML. These results also support the use of HLA-transgenic mice as a platform for generating TCRs targeting oncogene-derived epitopes in hematologic malignancies.

Monoclonal antibodies (mAbs) directed against MHC class I molecules (MHC-I) have been invaluable for a host of functions including tissue typing for transplantation, exploration of immune activation, and probing molecular structure and dynamics. We previously studied a set of murine mAbs directed against MHC-I to characterize their domain and allele specificity and demonstrated the consistency of structural identification of epitopes with prior mapping studies. Here, we report cryo-EM and X-ray crystal structures of a novel mAb (AF6-88.5) in complex with the mouse MHC-I molecule H2-Kb. We characterize the conformational epitope that is sensitive to polymorphic amino acid residues in the MHC-I extracellular domains. The structure of the mAb/MHC-I complex reveals contacts of the mAb to residues of the 2, 3, and {beta}2m domains and comparison to the unliganded mAb shows slight adjustments of the mAb CDRH3 and CDRL3 loops to accommodate the epitope surface. The structurally identified site overlaps with that seen by some coreceptors and immunoevasins. Amino acid sequence alignments and site-directed mutagenesis of H2-Kb, H2-Db, and {beta}2m explain the allelic specificity. These results emphasize the remarkable ability of antibodies to bind conformationally defined epitopes with exquisite discrimination and the contribution of MHC-I polymorphisms to antigenicity.

Amoebic gill disease (AGD), caused by the parasite Neoparamoeba perurans, is a major welfare and economic burden for the Atlantic salmon aquaculture industry. However, the spatial organisation of immune functions within the gill, the site of infection, remains poorly resolved. Here, we present the first spatial transcriptomic atlas of the Atlantic salmon gill affected by AGD, generated using 10x Genomics Visium on four AGD-positive fish, confirmed by gill scoring and quantitative PCR for parasite load. As no uninfected gills were included, this study maps the anatomical and immunological organisation of AGD-affected gills rather than defining AGD-specific pathology. Unsupervised clustering of spatial gene expression resolved distinct transcriptional domains that grouped into four principal anatomical compartments of the gill, including (i) epithelial and lamellar regions defined by keratin and osmoregulatory gene expression, (ii) gill arch regions enriched for connective tissue and smooth muscle markers, (iii) an erythroid-associated vascular cluster, and (iv) a skeletal muscle cluster with signatures of glycolysis and oxidative phosphorylation. Across these domains, we identified a spatially organised and diffused immune landscape, with pattern recognition receptors, antimicrobial effectors and chemokines concentrated at the filament surface, and immunoglobulin light chain transcripts consistent with B lymphocyte activity enriched toward the gill arch. Integration of the spatial data with a published single-nucleus reference atlas using reference-based deconvolution resolved the cellular identity underlying these domains and revealed frequent co-localisation of immune and structural cell types, suggesting regulated cell to cell communication within the gill-associated lymphoid tissue. Overall, our results show that the Atlantic salmon gill is not a transcriptionally uniform surface but a regionally specialised organ, with immune functions distributed across, and specialised within, distinct anatomical compartments

The human T cell repertoire is generated through recombination of a multitude of T cell receptor gene segments, yielding a complex array of T cell clones. T cell receptor beta (TRB) V gene segment defined, T cell clonal frequency when organized in correspondence with the respective V gene segment positions on the TRB genomic locus yields a periodic, undulating curve in the spatial domain. Using the genomic distance from the TRB-D1 segment to the TRB-V1-29 segments, spectral analysis was performed utilizing Lomb-Scargle periodogram (modified Fourier analysis) to obtain spectral power curves quantifying the TRB V clonal frequencies from 12 allogeneic stem cell transplant donors (baseline) and recipients (<100 days or b/w 100-365) using a variety of analytic software. Patients either underwent HLA matched related bone marrow or HLA matched unrelated blood stem cell transplantation, using PT-CY for the former and ATG for the latter. Spectral Power curves revealed dominant spectral peaks at wavelengths ranging from 113-335 millicycles/kb in the 12 donors, with consistent frequency domain spectral patterns, supporting similar use of V segments across healthy individuals. PT-CY recipients had power spectra closely corresponding to the respective donors, however the ATG recipients had relatively dispersed spectra, with spectral centroid shifted towards higher frequencies compared to donors and a reciprocal decline in the low frequency indices. Spectral power was concentrated in the <3 kb and 3-12 kb wavelengths in both groups, consistent with the periodicity observed in the relative V gene segment usage across the repertoire. The analyses reported here demonstrate that the healthy SCT donors have a spectral signature occupying short to intermediate wavelegnths in the frequency domain, PT CY recipients recover with donor-like spectra on the average, however ATG recipients tend to shift towards higher frequencies. These findings are consistent with a normal organized distribution of TRB V segment usage in healthy individuals, with PT-CY preserving this organization more consistently than ATG. Spectral (Fourier) analysis of TRB sequencing data provides a repertoire wide summary of T cell clonal distribution.

Pathogenesis inflicted by Entamoeba histolytica causes amoebic diarrhea and liver abscesses and is one of the leading causes of mortality from parasitic disease worldwide. Preventive therapeutics in the form of a vaccine could be highly effective at providing umbrella protection for a vulnerable community. In this study, a group of ten putative hypothetical surface N-linked glycoproteins was examined to assess their potential as vaccine candidates and/or diagnostic markers against amoebic intestinal colitis and liver abscesses. To evaluate the immunogenicity of putative surface glycoproteins, we used Entamoeba histolytica-infected patients sera from Bangladesh and then assessed the titer of antibody these glycoproteins elicited in patients by enzyme-linked immunosorbent assay (ELISA) and immunoblot. Based on this study, eight of ten surface glycoproteins were found immunogenic, as specific antibodies against these glycoproteins were detected in patients sera. Three of the immunogenic glycoproteins showed strong IgG antibody responses in both patients with intestinal amoebiasis and those with liver abscess. On the other hand, the other two glycoproteins showed the presence of specific serum antibodies exclusively in patients with amoebic liver abscesses, not in individuals with amoebic colitis. The remaining two glycoproteins showed more specific sera antibodies against ALA, but the preference was not very distinct. Immunolocalization with a specific antibody against the most immunogenic glycoproteins further confirmed their presence in the cell membrane. This differential immunogenicity of these glycoproteins in the two groups of patients qualifies them to become prospective sera-based diagnostic markers and also has the potential to become vaccine candidates for amoebiasis protection.

This 28-color panel was developed to identify classical and non-classical T lymphocytes in decidual leukocytes and peripheral blood mononuclear cells (PBMC) of pregnant rhesus macaques. By profiling these T lymphocytes, we can investigate how maternal immunity balances tolerance to fetal antigens with protection against vertically transmitted pathogens. The selected markers define memory populations and characterize tissue residency, activation, proliferation, cytotoxicity, trafficking, and exhaustion status. This panel also delineates B lymphocytes and NK cells to confirm expected frequencies. The utility of this panel is aimed at evaluating cellular immune correlates of protection against congenital infections at the maternal-fetal interface and PBMC in rhesus macaques.

Core fucosylation (alpha1,6-fucosylation) of N-glycans, catalyzed solely by fucosyltransferase 8 (FUT8), plays important roles in development, immunity, and antibody effector functions. Here we report the generation of Fut8 floxed mice using a CRISPR/Cas9-based Extreme Genome Editing (EGE) system, in which loxP sites flank exon 8 of the Fut8 gene and a LoxP-STOP-LoxP-RFP cassette was knocked in downstream of the promoter, rendering the targeted allele functionally null before Cre-mediated recombination. Crossing floxed mice with CMV-Cre transgenic mice yielded complete knockout mice carrying the Cre-recombined allele. A PCR-based genotyping method was established that unambiguously distinguishes the wild-type, heterozygous, and homozygous genotypes (+/+, delta/+, and delta/delta). Intercrossing of heterozygous mice revealed that homozygous knockout mice die during the early postnatal period, consistent with previous reports, whereas heterozygous mice are viable. Flow cytometric analysis of AAL binding to splenic B cells and AAL lectin blotting both demonstrated markedly reduced core fucosylation in heterozygous mice (60.0 +/- 6.8% and approximately 48% of wild-type levels, respectively). These results show that disruption of a single Fut8 allele substantially reduces core fucosylation, and the mouse model described here provides a practical tool for functional studies of core fucosylation.

Introduction: How much of the variable (V) and joining (J) gene identity of a T-cell receptor is recoverable from its third complementarity-determining region (CDR3) amino-acid sequence alone? Immune repertoire studies often report the CDR3 with V and J annotation that is missing, low-confidence, or inconsistent, so what the CDR3 alone can and cannot fix is both a basic question about the receptor and a practical one for reading those repertoires. Methods: For each of 118,096 pooled human rearrangements (37,687 and 80,409 {beta}) we computed the posterior distribution over candidate genes under a generative model of V(D)J recombination and under its post-selection counterpart, and measured recoverability by conditional entropy, the candidate-list size needed to contain the annotated gene, the fraction of sequences admitting a high-confidence single-gene call, and the structure of gene-by-gene confusion. Results: The J gene was nearly determined by the CDR3 in both chains. The V gene was only partially recoverable, and behaved as a group rather than a gene: junctional trimming and non-templated insertion, together with the loss of synonymous codon information in translation, leave sets of mutually confusable V genes whose grouping departs sharply from germline family nomenclature (adjusted Rand index 0.05 for and 0.21 for {beta}). Selection sharpened the V posterior modestly (usage-controlled entropy shift -0.06 nats for and -0.28 for {beta}) and redistributed which V gene was most probable, a locus-scale rewrite in {beta} against a mild reweight in . Both the recoverability measurements and the confusion grouping reproduced in two held-out tumor cohorts. Discussion: V identity is an emergent, system-level property of the repertoire, set jointly by recombination and selection and invisible in any single rearrangement, so it should be reported as a calibrated group rather than a single gene. We also release the pipeline with a computational tool which can output a set of candidate genes with confidence values given a CDR3 sequence.

Production of aberrant glycans by cancer cells constitutes a key immunosuppressive strategy to avoid destruction by immune cells. Although sialic acid-containing glycans are known to dampen the activation of lymphocytes, including Natural Killer (NK) cells, the role of fucose-containing glycans remains poorly characterized. In this work, we explored the role of Lewis X (LeX) in cancer cell-NK cell interactions. We induced ectopic expression of FUT9, an 1-3/4-fucosyltransferase, in two colorectal cancer cell lines and showed this enzyme only synthesized LeX structures but not sialyl-LeX. FUT9 introduction was not associated with altered MHC class I surface expression, nor with CD2 (which has been proposed as a receptor for LeX) binding to cancer cells. By inhibiting fucosylation we could demonstrate that CD2 binding was furthermore independent of surface fucosylated glycans in three independent cell lines. Lastly, FUT9/LeX had a limited role in cancer cell destruction and expression of activation markers by NK cells. Overall, our study suggests that, unlike sialylated glycans, 1-3/4-fucosylated glycans have limited impact on cancer cell evasion of NK cell-mediated destruction.

Background: Transplant arterial injury is an underlying feature of acute organ transplant rejection and is a main cause of late heart transplant failure. The role of the gut microbiota, and especially specific microbial components of this community, in controlling immune responses that cause this aspect of rejection is poorly understood. Methods: We utilized a murine aortic interposition model of transplant arterial injury to investigate the role of the gut commensal bacteria, Akkermansia muciniphila, in controlling immune responses in transplant arteries. Results: Early life treatment of female mice with broad spectrum antibiotics, which delayed colonization of the intestinal tract with bacteria until after weaning, led to the development of dysbiosis in adults that was characterized by the absence of A. muciniphila. This was related to an elevation in systemic levels of CCL2 and a reduction in the immunomodulatory short-chain fatty acid, propionate. When transplant arterial injury was examined, there was more arterial injury indicative of acute rejection and increased intimal thickening reflective of transplant arteriosclerosis in grafts from dysbiotic mice compared to controls. Dysbiosis also increased macrophage accumulation early after transplantation in dysbiotic mice. Notably, restoring A. muciniphila in the gut microbiota of dysbiotic mice through voluntary oral administration in infants ameliorated macrophage-mediated transplant arterial injury. Conclusions: A. muciniphila is an immunomodulatory component of the gut microbiota that protects against vascular injury and pathology in organ transplantation.

Grecia Salentina (GS) is the label assigned to a geographic area in Southern Italy where a Greek dialect has historically been spoken. The origins of this Greek-speaking community, whether dating from ancient or Medieval settlement, are a controversial and essentially unsolved issue. To evaluate which historical-linguistic scenario is best supported on genomic grounds, we used whole genome sequencing of 27 GS natives and 21 controls, embedding them in a 799 modern samples dataset in which Greece and Anatolia were evenly represented, an uncommon feature in the genomic literature on the area. We considered different aspects of the genetic structuring, at different spatial and temporal scales. Analyses also included 4021 ancient samples from the literature. All analyses pointed to the same conclusion: the GS genomic profile displays the same characteristic features of the rest of Southern Italy, with no definite evidence for a single source population from outside Italy. Correspondingly, we detected strong genetic connectivity among GS municipalities and between GS and the rest of Italy. Only a subset of our analyses suggested a slightly increased affinity of GS with Greece, or with the Anatolian peninsula. These results indicate that GS has been all but a genetically closed community, and that the Greek language did not act as a barrier to gene flow. By endorsing a ''transient mobility model'' we support the most recent linguistic hypothesis: the prolonged resilience of the Greek language in GS, maintained in situ and periodically rejuvenated through recurrent external inputs from the Greek and Byzantine worlds.

Genetic screens in immune cells enable the systematic interrogation of gene function at scale, uncovering key regulators of cell functions such as tumor cell killing and persistence. However, existing datasets typically focus on specific biological questions, employ targeted gene panels, are generated under diverse experimental conditions, and are not readily accessible, which together limit their integration and future usability. To address this, we developed the Functional Immunogenomics and Transcriptomics Database (FITdb), a freely accessible resource that harmonizes functional genomics datasets for the study of immune cell biology. FITdb currently integrates 43 independent functional genetics screens, including 32 pooled and 11 single-cell screens, spanning 20, 696 mouse genes and 22, 293 human genes across 199 immune cell types and conditions. All datasets are uniformly re-analyzed to enable cross-study comparisons. FITdb provides intuitive, gene-centric visualizations, detailed exploration of individual screens, and access to sgRNA-level data. Additionally, built-in tools such as "Compare MyGeneSet" and "Compare MyScreen" identify statistically significant overlaps between user-defined gene lists and functional gene sets in FITdb, and enable direct comparison of user-generated screening data with existing datasets, respectively. Together, FITdb provides a comprehensive, user-friendly platform for accelerating the discovery of immune regulatory programs. The database is freely available at https://fitdb.lji.org. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=100 SRC="FIGDIR/small/741304v1_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@17ce74borg.highwire.dtl.DTLVardef@134efbdorg.highwire.dtl.DTLVardef@6787deorg.highwire.dtl.DTLVardef@1090007_HPS_FORMAT_FIGEXP M_FIG C_FIG

Chinese bahaba (Bahaba taipingensis) is a critically endangered marine fish that has been commercially extinct in the wild. Conservation-oriented captive breeding has become an effective strategy for rescuing such endangered species, but concerns about inbreeding depression often remain. Here, after merely two generations of closed breeding from 18 wild founders, Chinese bahaba exhibited severe growth depression, with body length and weight diverging by more than three-fold. To further investigate the early genomic consequences of captive breeding, we analyzed whole-genome sequences from 348 F2 individuals together with 19 wild individuals from the same marine region. While genome-wide genetic diversity was overall preserved, closed breeding rapidly partitioned the F2 population into eight distinct genetic lineages. A significant elevation in genomic inbreeding was observed to facilitate the homozygous exposure of recessive deleterious mutations, which was strongly correlated with growth decline. An integrative framework combining GWAS, gene-level burden test, and ROH hotspots was applied to dissect the genetic architecture underlying growth decline, which converged predominantly on skeletal scaffolding and immune regulation. This was evidenced by candidate genes related to skeleton development and homeostasis (e.g. fam20b, c-fos, trpv5, and il23r), the GH/IGF axis (e.g. socs1a), and immune/inflammatory pathways (e.g. il23r, nlrp7, cd163, il12rb2), as well as calcium ion transport pathway. Together, our findings provide novel insights into the genomic consequences and genetic architecture of growth decline under captive conditions in Chinese bahaba, and offer critical guidance for genetic management in captive conservation programs of endangered species.

Genetic sex-determination mechanisms evolve rapidly in teleost fishes and are diverse within Beloniformes. In the present study, the sex-determination system of Pacific saury (Cololabis saira) was confirmed using double-digest, restriction-site-associated DNA sequencing (ddRAD-seq) and pooled whole-genome sequencing (Pool-seq), and a DNA marker was developed for inferring genetic sex. DNA sequence analysis detected numerous markers occurring predominantly or exclusively in phenotypic females suggesting a ZZ/ZW sex-determination system. Mapping of ddRAD-seq loci showed that these markers were concentrated within a 3-19 Mb region of chromosome 17 (Chr17). Pool-seq analyses also revealed elevated FST, sex-specific differences in sequencing depth, and nucleotide diversity within this region, supporting a ZZ/ZW sex-determination system involving Chr17. A PCR marker designated female-specific 1 (FS1), developed from a female-associated ddRAD sequence unmapped from the male-derived reference genome, was detected in all 43 phenotypic females and none of the 50 phenotypic males collected in 2025. In an independent sample collected in 2026, FS1 was detected in all 19 phenotypic females and one of the 29 phenotypic males, resulting in 97.9% concordance with phenotypic sex. The FS1-positive male may represent a genotypic-phenotypic sex mismatch or reflect recombination between FS1 and the causal sex-determining region; the linkage of FS1 to the W chromosome remains unconfirmed. Chromosome-scale synteny analysis showed that Pacific saury Chr17 and the sex chromosomes of Hyporhamphus sajori and Oryzias latipes are nonhomologous to one another. These findings reveal substantial sex-chromosome diversity among beloniform fishes and establish a basis for investigating genetic sex determination and genotypic-phenotypic sex concordance in wild Pacific saury.

Infections due to Cryptococcus species are estimated to cause over 100,000 deaths a year. No cryptococcal vaccines are approved for human use. We have shown that vaccine formulations consisting of C. neoformans chitin deacetylase (Cda)2 and Cda1 adjuvanted with Cationic Adjuvant Formulation 01 (CAF01) protect mice against experimental cryptococcosis by a mechanism dependent upon CD4+ T cells. Here, using overlapping peptide libraries, we mapped epitopes in Cda2 and Cda1 that stimulated interferon-gamma (IFN{gamma}) release from splenocytes of C57BL/6 and DR4 mice immunized with these proteins. DR4 mice lack mouse major histocompatibility class II (MHC-II) proteins and express chimeric MHC-II proteins with the specificity of the human HLA-DR allele, HLA-DRB1*04:01. Experimental results were then compared with MHC-II binding predictions using the Immune Epitope Database (IEDB) NetMHCIIpan 4.1 BA MHC-II epitope prediction tool. Unique epitopes in Cda2 and Cda1 were discovered for each mouse strain, some of which were not predicted to bind well to MHC-II. CD4+ T cells were responsible for cytokine release as IFN{gamma} production was lost if CD4+ T cells were depleted from the splenocyte population. Finally, we tested a hybrid recombinant protein that consisted of portions of Cda2 and Cda1 containing the MHC-II/CD4+ T cell epitopes which induce CD4+ T cells in DR4 mice. When administered as a CAF01-adjuvanted vaccine, the hybrid protein protected DR4 mice from an otherwise lethal C. neoformans pulmonary challenge. These results provide a proof of principle regarding the utility of MHC-II/CD4+ T cell epitope mapping in cryptococcal vaccine development.

Adaptive immune-receptor repertoire sequencing (AIRRseq) is crucial for understanding immune system diversity and its relationship to disease dynamics. Partitioning of total B and T cells into their major subsets with distinct immunological functions - IgM+ vs. class-switched B cells (IgG+ > IgA+) and CD4+ vs. CD8+ T cells, respectively - allows for AIRRseq-based analysis of the unique contributions of each compartment to the overall immune response, a major advantage over traditional bulk sequencing workflows. However, data from these subsets is not directly comparable with the vast majority of publicly available AIRRseq data, which comes from unfractionated B and T cells, an important incompatibility. Here we investigate computational methods for reconstructing complete AIRRseq repertoires from partitioned B and T cell subsets in diverse individuals. Peripheral blood mononuclear cells (PBMCs) were partitioned via positive selection of IgM+ B-cell subsets and CD4+ T cells using immunomagnetic beads; genomic DNA was then extracted and B- and T-cell receptors were sequenced. Four reconstruction methods are introduced and evaluated for concordance with matching unpartitioned repertoires to assess preservation of key repertoire characteristics. Results show that these methods enable accurate estimates of overall immune-repertoire diversity from B- and T-cell subsets in a way that simply pooling the sequence data from sub-repertoires cannot.

Batoids (rays, skates, and relatives) are among the most threatened cartilaginous fishes globally, yet the molecular diversity of Peruvian taxa remains poorly evaluated. Furthermore, regional barcode sequences for high-conservation-priority taxa, such as sawfish, manta, and devil rays, are often restricted to private records, hindering essential phylogeographic and population structure assessments. To bridge this gap, we developed BATOseq-PE, the first public genetic reference library for Peruvian marine batoids, covering 14 species sequenced in vitro from local specimens, complemented by a novel in silico assembled mitogenome for Notoraja martinezi. This open-access repository contributes 73 novel COI barcodes, providing robust taxonomic resolution across 15 molecular operational taxonomic units (MOTUs) and Barcode Index Numbers (BINs). Notably, we provide the first Peruvian public records for high-priority species such as Mobula munkiana, Mobula thurstoni, Myliobatis peruviana, Rostroraja velezi, and the first global public barcodes for N. martinezi and Zapteryx xyster. By coupling BATOseq-PE with global datasets, we conducted the first multi-taxa screening for delimitation and phylogeographic assessments on Peruvian batoids, revealing a cryptic lineage within R. velezi and genetic connectivity patterns suggesting female philopatry in Mobula mobular. Finally, by integrating nucleotide diversity into a Genetic Diversity Risk Indicator (GDRI) alongside ecological and fishery data, we identified an alarming trend where heavy fishing pressure overlaps with extinction risk and depleted genetic diversity, allowing us to suggest data-driven, tailored management strategies. BATOseq-PE represents a valuable resource to accelerate taxonomic and population assessments, ultimately fostering ray conservation through the integration of genetic frameworks into fishery management.