Journal of immunology最新文献

Artificial intelligence (AI) and machine learning (ML) are transforming biotechnology and playing a key role in bioeconomy. One of the most important measurement capabilities at the forefront of biotechnology innovations is flow cytometry (FCM), a high-throughput, single-cell analysis platform technology. However, the quality and consistency of FCM data can vary significantly across laboratories and study datasets, resulting in millions of FCM datasets siloed for their use in AI applications. This workshop focuses on overcoming challenges and identifying solutions that include essential measurements, reference controls, AI-ready reference data, and current AI/ML models. It aims to advance AI/ML applications in FCM and related data.

A key challenge in B-cell lineage-based vaccine design is understanding the "inducibility" of target neutralizing antibodies-the ability of these antibodies to be elicited by presentation of an immunogen. Induction relies on a combination of stochastic diversification and immunogen-based selection, and as a result is heavily dependent on the probabilistic accessibility of induction pathways. We explored inducibility using a detailed stochastic model of the somatic hypermutation process-which captures the critical "context-dependence" of sequence mutation rates-coupled to a stochastic population model for B-cell clonal maturation. The model is used to calculate inducibilities for a set of critical mutations required by the HIV broadly neutralizing antibody (bnAb) CH235.12. The results provide insight into barriers to the elicitation of HIV bnAbs and explain experimental results observed in mouse models. Our models enable detailed analysis of maturation pathway probabilities, allowing us to identify opportunities for the design of boosting immunogens aimed at elicitation of CH235.12 via a sequential vaccination regimen.

During the progression of acetaminophen (N-acetyl-para-aminophenol [APAP])-induced liver injury, the innate immune response is implicated in the induction of tissue damage. However, the precise cellular and molecular mechanisms underlying this process are not yet completely elucidated. CARD9 is known to modulate the activation of the NF-κB family of transcription factors during anti-pathogen immune responses, but its involvement in sterile APAP-induced hepatitis has not been heretofore studied. To investigate this, we employed an APAP-induced liver injury model, which simulates the initial toxic demise of hepatocytes, followed by innate immune activation. Our findings reveal that CARD9 expression within Kupffer cells exacerbates liver damage by amplifying the production of proinflammatory factors, which are known to play a pathological role in noninfectious conditions. Furthermore, our study identifies TREM2 receptors on Kupffer cells as capable of recognizing components released upon cell death and operating as upstream signaling receptors to orchestrate tissue damage during sterile inflammation.

Matrix metalloproteinase 9 (MMP-9) plays a key role in the pathogenesis of inflammatory diseases and is upregulated by TNF-α. ITE (2-[1'H-indole-3'-carbonyl]-thiazole-4-carboxylic acid methyl ester) functions as an endogenous ligand for the aryl hydrocarbon receptor and is involved in inflammation. It is still uncertain whether ITE could affect TNF-α-induced MMP-9 expression in monocytic cells. In this study, we explored the effect of ITE on TNF-α-induced MMP-9 expression and the underlying mechanisms involved. Our results show that pretreatment of THP-1 monocytic cells with ITE significantly blocked TNF-α-induced MMP-9 expression at both the mRNA and protein secretion levels. Similar results were seen in primary human monocytes. The inhibition of MMP-9 by ITE occurs independently of TNFR1/2 modulation and apoptotic processes. RNA transcription data revealed that ITE suppresses the genes associated with inflammatory pathways. Mechanistically, histone modification profiling identified H3K9 acetylation as an epigenetic regulatory mark of TNF-α-induced MMP-9 expression. ChIP-qPCR data revealed that ITE pretreatment decreased TNF-α-triggered transcriptionally permissive acetylation marks at H3K9 in the MMP-9 promoter. Pharmacological inhibition of histone acetylation mimics the action of ITE in suppressing TNF-α-induced MMP-9 gene expression. Conversely, the acetylation induced by trichostatin A effectively reverses the inhibitory action of ITE. Moreover, increased TNF-α-induced binding of NF-κB or AP-1 at the MMP-9 promoter region was inhibited by ITE, resulting in suppression of MMP-9 gene expression. In conclusion, our study demonstrates that ITE reduces the TNF-α-induced MMP-9 expression via the H3K9 acetylation/NF-κB/AP-1 axis, highlighting a potential mechanism for mitigating MMP-9-related inflammatory disorders.

Nucleoporin 93 (Nup93), a key component of the nuclear pore complex, is involved in various cellular processes, such as immune signaling pathway. In mammals, Nup93 positively regulates the RLR signaling pathway by targeting TBK1 and IRF3. However, the role of Nup93 in teleost immunity remains unexplored. In this study, we have cloned and characterized the Nup93 homolog (bcNup93) in black carp. bcNup93 consists of 821 amino acids, composed of a coiled-coil (CC) domain and a NIC96 domain. Quantitative RT-PCR analysis revealed fluctuations in bcNup93 mRNA levels in response to spring viremia of carp virus, grass carp reovirus, and poly(I:C) stimulation. bcNup93 migrated around 93 kDa in an immunoblotting assay, and immunofluorescence and nucleo-cytoplasmic fractionation assays identified its predominant localization in the nuclear envelope. Knockdown of bcNup93 in host cells significantly enhanced the expression of interferons and interferon-stimulated genes, as well as the antiviral capacity, suggesting a suppressive role of bcNup93 in antiviral immunity. In addition, bcNup93 knockdown in black carp juveniles led to reduced viral gene expression in multiple tissues postinfection, as well as an enhanced survival ratio. Mechanistically, bcNup93 interacts with bcIRF3/7 and attenuates their protein levels by lysosomal degradation pathways and decreases their protein stability or activity by degrading K63-linked ubiquitination of bcIRF3/7. Further analysis of bcNup93 functional domains shows that both CC and NIC96 domains are critical for its inhibitory effects on bcIRF3/7-mediated antiviral signaling. In conclusion, these findings demonstrate that bcNup93 negatively modulates the antiviral immune response in black carp by attenuating bcIRF3/7 protein levels.

Graft failure (GF) following hematopoietic stem cell transplantation (HSCT) remains a major complication particularly in the setting of human leukocyte antigen (HLA)-mismatched grafts where residual host lymphocytes can drive immune-mediated rejection. While strategies to mitigate GF have been explored, such as intensified conditioning or donor T cell supplementation, these approaches carry significant risks, including increased toxicity and graft-versus-host disease (GVHD). Recent studies have highlighted the glucagon-like peptide-1 receptor (GLP1R) as a critical regulator of immune homeostasis, yet its role in HSC engraftment remains unexplored. Here, we demonstrated that GLP1R deficiency in recipient mice leads to a profound increase in GF following MHC-mismatched allogeneic HSCT. Although GLP1R knockout (GLP1RKO) and wild-type (WT) mice exhibited comparable survival and engraftment following syngeneic or minor antigen-mismatched transplants, GLP1RKO mice undergoing MHC-mismatched HSCT experienced significantly greater weight loss, earlier mortality, and reduced donor chimerism. Histologic and cytokine analyses confirmed that this phenotype is not driven by GVHD, but rather by early graft rejection. Depletion of CD90+ recipient T cells prior to transplantation rescued engraftment in GLP1RKO mice, further supporting a model in which GLP1R signaling restrains host lymphocyte-mediated graft rejection. These findings identify GLP1R as a novel regulator of allogeneic HSC engraftment and suggest that GLP1R agonists, widely used for metabolic disorders, may have therapeutic potential in preventing HSC graft rejection. Given the lack of targeted interventions for HSC graft rejection, further studies are warranted to investigate GLP1R-directed therapies in the context of allogeneic HSCT.

Sepsis followed by multiple organ failure is a leading cause of death in noncoronary intensive care units. While the NLRC4 inflammasome has been shown to play a crucial role in the innate immune response, the role of NLRC4 in sepsis remains unclear. Here, we used NLRC4 gene-deficient mice to explore its role in cecal ligation and puncture (CLP)-induced polymicrobial sepsis. Survival, bacterial clearance in the lung and extrapulmonary organs, and leukocyte influx to the peritoneum were determined. Chemokines and cytokines in the peritoneal fluid (PF) were quantified using ELISA. Mice were co-housed to compare the gut microbiota's effect on bacterial burden following sepsis. Here, we report that NLRC4 deficiency improves host survival and bacterial clearance in mice with CLP-induced sepsis. Nlrc4-/- mice displayed reduced numbers of total leukocytes in the PF, including neutrophils compared to wild-type (WT) mice at 12 and 24 h post-CLP, although the recruitment of macrophages in NLRC4 knockout mice was higher at 12 h. Nlrc4-/- mice displayed lower levels of cytokines and chemokines in PF following sepsis. Co-housing of WT and Nlrc4-/- mice suggests that NLRC4 regulates host defense in CLP-induced sepsis independently of gut microbiota. Depletion of macrophages demonstrated that NLRC4 deficiency protects macrophages from sepsis-induced immune dysfunction. Moreover, we observed higher CD4+, CD8+, IFN-γ+CD8+, and NK cell subsets in the spleen and lower level of apoptosis of spleen cells of NLRC4-deficient mice after sepsis. Overall, these findings identify that NLRC4 activation has a detrimental role in sepsis through modulating macrophages and T-cell responses.

Disruptor of telomeric silencing 1-like (DOT1L) is an epigenetic regulator that promotes gene expression by methylating lysine 79 on histone H3 and recruits transcription factors to gene targets. DOT1L is also an oncogenic driver in cancers that affect developing lymphocytes, yet how DOT1L activity regulates B-cell maturation remains poorly defined. Here, we use deep-sequencing and conditional knockout models to elucidate gene targets of H3K79me2, and the mechanistic contribution of DOT1L, during key stages of murine B-cell development. In the bone marrow, Dot1l was upregulated in pro B cells. Deep sequencing revealed that H3K79me2 accumulated during maturation. The genomic distribution of H3K79me2 peaks indicated that DOT1L regulates transcription and the cell cycle across different stages of B-cell development. As such, DOT1L was found to be essential for pre B-cell expansion, leading to a significant decrease in pre B cells in the absence of DOT1L and a skewing of the B-cell receptor repertoire to favor proximal VH usage. In addition to the effective generation of a diverse B-cell pool, DOT1L was also required to establish the marginal zone (MZ) B-cell gene expression program. Attenuation of MZ B cells and a bottlenecking at the pre-MZ B-cell stage in Dot1L-deficient mice correlated to H3K79me2 peaks at key MZ-regulatory genes such as Lfng and Dock10 in developing B cells. In contrast, Dot1l was reexpressed in germinal center (GC) B cells postimmunization to deposit H3K79me2 at key GC B-cell gene loci during GC differentiation. Together, these data demonstrate a vital role for DOT1L during B-cell lymphopoiesis, MZ B-cell generation, and GC B-cell biology.

Mucosa-associated invariant T (MAIT) cells are innate-like T cells abundant in mucosal tissues, liver, and blood. MAIT cells recognize riboflavin metabolite-derived microbial antigens displayed by the MHC-I-related protein (MR1) and respond by producing cytokines, killing infected cells, and suppressing microbial growth. We previously demonstrated that MAIT cell numbers and function are reduced in chronic HIV-1, potentially increasing susceptibility to microbial coinfections. Here we assessed colorectal MAIT cells from people living with HIV-1 (PLWH, n = 36) and people without HIV-1 (PWOH, n = 22) by flow cytometry. In PBMCs, MAIT cells were less abundant in PLWH compared to PWOH. However, colorectal MAIT cell percentages were comparable in both groups, suggesting reduced loss from gut compared to blood in HIV-1 infection, or redistribution from blood to mucosae. In both groups, the majority of mucosal MAIT cells expressed CD8 and were enriched for CD8αα; a minority expressed CD4 or were double negative. Colorectal MAIT cells expressed CD69 and CD45RO, indicating a tissue-resident memory phenotype. Mucosal MAIT cells from PWOH expressed high perforin compared to PLWH, although granzyme B was low as compared to blood counterparts. Intracellular cytokine staining revealed robust cytokine production when stimulated with PMA/ionomycin. However, while blood MAIT cells responded strongly to inactivated Escherichia coli, mucosal MAIT cells responded poorly to this stimulus. Thus, gastrointestinal MAIT cells may be partially unresponsive toward commensal microbes, while remaining responsive to other stimuli. These findings provide novel insights into the functional profile of gastrointestinal MAIT cells in the context of chronic HIV-1.

PTEN-induced kinase 1 (PINK1)-mediated mitophagy, a classic mechanism underlying the elimination of damaged mitochondria, plays a crucial role in the immune evasion of bacteria. In the present study, we found that Edwardsiella piscicida, an intracellular pathogenic bacterium that infects fish, could induce PINK1-mediated mitophagy to enhance its survival and virulence in largemouth bass (Micropterus salmoides). E. piscicida infection damaged mitochondria in the liver or hepatocytes of largemouth bass and induced PINK1-mediated mitophagy, as confirmed by knockdown of PINK1, transmission electron microscopy, and qPCR analysis. Knockdown of PINK1 decreased the intracellular growth of E. piscicida and lowered the mortality rate of fish infected with E. piscicida. Additionally, qPCR revealed that knockdown of PINK1 increased the production of reactive oxygen species (ROS) and the expression levels of several immune-related genes, including piscidin-1, piscidin-3, TNF-α, TGF-β, and IL-10. Our results suggest that the PINK1-mediated pathway induced by E. piscicida may facilitate the survival of E. piscicida by inhibiting the production of ROS and regulating the expression of immune-related host genes. Our study provides new insights into the mechanism of immune escape of E. piscicida in largemouth bass.