ImmunoHorizons最新文献

Ficolins, encoded by FCN genes, are key pattern recognition molecules of the lectin complement pathway involved in immune complex clearance, a process often impaired in systemic lupus erythematosus (SLE). Genetic polymorphisms in FCN genes may influence disease susceptibility. However, their functional significance in SLE remains unclear. The present study aimed to investigate the association of selected FCN gene single-nucleotide polymorphisms (SNPs) with SLE, lupus nephritis (LN), and serum ficolin levels in a Western Indian cohort. Seven SNPs in FCN1 (rs2989727, rs1071583), FCN2 (rs7851696, rs17549193, rs7865453, rs17514136), and FCN3 (rs3813800) were genotyped in 200 SLE patients and 200 healthy controls using polymerase chain reaction (PCR) sequence-specific primer and PCR restriction fragment length polymorphism. Serum ficolin-1, -2, and -3 levels were measured using ELISA. Statistical analysis included χ2 test, Kruskal-Wallis test, and logistic regression to assess associations and calculate odds ratios with 95% confidence intervals. The analysis identified significant associations of FCN2 rs7851696, rs7865453, and rs17514136, as well as FCN3 rs3813800, with SLE susceptibility. Among LN patients, FCN1 rs2989727 and rs1071583, FCN2 rs17514136, and FCN3 rs3813800 showed significant associations. FCN3 rs3813800 was significantly associated with ficolin-3 levels, while FCN2 rs7865453 was associated with complement component 1q-circulation immune complex levels. These findings provide novel insight into associations of FCN gene polymorphisms with SLE and LN susceptibility, with genotype-phenotype correlations suggesting their biological relevance. Future longitudinal and mechanistic studies are warranted to validate these associations and explore their therapeutic potential.

Tuberculosis (TB) remains a worldwide public health threat, in part because of the limited efficacy of current BCG vaccination. Respiratory infection with Mycobacterium tuberculosis (Mtb) is most often followed by the development of protective immunity that contains the pathogen, resulting in latent tuberculosis infection (LTBI). We previously introduced bronchoscopic challenge of LTBI individuals using instillation of purified protein derivative (PPD) of Mtb to model specific induced local recall responses in the human lung. Here, we examined phenotypic and functional aspects of human airway CD4+ T cell populations in LTBI that correlate with protection from Mtb in animal infection models. Baseline bronchoalveolar lavage (BAL) was enriched for CD4+ T cells expressing the KLRG-/CD69+ tissue resident-memory (TRM) phenotype. Both Th1 (CCR6-CCR4-CXCR3+) and Th1* (CCR6+CCR4-CXCR3+) CD4+ T cell subsets demonstrated polyfunctional IFN-γ+TNF-α+ cytokine responses in response to in vitro PPD stimulation. Bronchoscopic PPD challenge, although leading to less robust cellular recruitment than observed previously, preserved the predominance of KLRG1-CD69+ TRM and also of CD4+ T cells that displayed IFN-γ+TNF-α+ dual cytokine production in response to PPD. CD4+ T cells of both control and PPD challenged human lung segments displayed increased expression of the protective CD153 molecule; CD153 expression also correlated with increased cytokine polyfunctionality, particularly of polyfunctional IFN-γ+IL-2+TNF-α+ and IFN-γ+TNF-α+ dual-positive cells. These results support the utility of BAL studies in LTBI to model human correlates of protection from Mtb with potential applicability to the design and initial evaluation of novel approaches to TB vaccination.

Influenza infection predisposes individuals to secondary pneumonia caused by a range of pathogens, including both bacterial and fungal organisms. Neutrophils are critical effector cells during infection. In this study, we analyzed the transcriptional pathways of lung neutrophils isolated from mouse models of influenza-associated pulmonary aspergillosis (IAPA) and post-influenza methicillin-resistant Staphylococcus aureus (MRSA) pneumonia to examine the immunopathological mechanisms underlying post-influenza super-infection. Pathways associated with neutrophil chemotaxis and degranulation were inhibited in IAPA compared to singular A. fumigatus infection and pathways associated with neutrophil recruitment and phagocytosis were inhibited in IAPA compared to singular influenza infection. Pathways associated with neutrophil recruitment and degranulation were inhibited in post-influenza MRSA pneumonia compared to singular MRSA infection and pathways associated with cytokine signaling were inhibited in post-influenza MRSA pneumonia compared to singular influenza infection. When the 2 types of super-infection were directly compared, pathways related to cytokine induction and neutrophil function were inhibited in IAPA neutrophils compared to post-influenza MRSA pneumonia. These data demonstrate that influenza causes neutrophil dysfunction, predisposing to secondary fungal and bacterial infections.

Surgery for local control is a cornerstone of anticancer therapy with demonstrated survival benefit. However, surgery-induced modulation of antitumor immunity may also contribute to cancer progression and relapse. Despite evidence for a pro-tumor surgery effect in adult cancers, there remain significant knowledge gaps as to the influence surgery has on recurrence or metastatic outgrowth in pediatric cancers. High-risk neuroblastoma (HR-NB) is the most common extracranial solid tumor of childhood. While almost all children with HR-NB undergo surgery, nearly 50% suffer metastatic relapse and succumb to their disease. To ascertain if surgery may contribute to recurrence in HR-NB, we developed a mouse model to comprehensively interrogate the systemic effect of surgery on distant tumor growth and immune modulation. This model demonstrated that MYCN-amplified HR-NB tumor growth was accelerated by surgery compared to tumor-bearing mice without surgical stress. Accelerated tumor growth was absent in HR-NB cells engrafted to immune deficient mice, suggesting that an intact immune system may be needed for surgery to exert its pro-growth effect on distant tumor cells. Consistent with that genetic ablation model, flow cytometry measured a decrease in splenic macrophages (Mϕ) and dendritic cells (DC) and an increase in myeloid-derived suppressor cells (MDSC) after surgery. Perioperative treatment with polyinosinic-polycytidylic acid [poly(I:C)] ameliorated surgery-induced tumor growth. These findings provide direct insight into the systemic surgical effect on pediatric solid tumor growth and identify innate immune adjuvants as a potential perioperative treatment to mitigate this effect.

Neutrophils are essential cellular components of innate immunity. After injury, they migrate into tissues following chemotactic gradients to phagocytose pathogens or respond to tissue damage. This multistep process is tightly regulated, and defects at any stage can lead to increased bacterial infections. Identifying specific defects requires specialized assays, yet teaching the assessment of these functions in a laboratory setting presents challenges. At the University of South Australia, undergraduate immunology is taught to students training as laboratory medicine scientists, who must understand how to assess neutrophil function. However, demonstrating chemotaxis in the laboratory is not possible due to a lack of inverted microscopes, restricted laboratory time, and lack of patient samples with defined neutrophil defects. To address this, we developed a computer simulation replicating the under-agarose method of quantifying neutrophil chemotaxis. In the simulation, students load both "control" and "patient" samples and measure both random and directed migration toward 5 common chemoattractants. Using an in-house-defined reference range, they determine the immunological status of each sample. The simulation's impact was evaluated using a mixed-methods approach, incorporating Likert-scale questionnaires, free-text feedback, and scores from laboratory reports. Student feedback was overwhelmingly positive, with the simulation significantly enhancing their understanding of neutrophil function. All students successfully completed the report, typically achieving high grades. These findings support the use of authentic computer-based simulations as effective alternatives for teaching complex immunological techniques in resource-limited settings, offering a practical and engaging solution to challenges in traditional laboratory instruction.

Macrophages are important sites of bacterial replication and host immune responses during Mycobacterium tuberculosis (Mtb) infection with distinct roles for alveolar macrophages (AMs) early in infection and monocyte-derived macrophages (MDMs) later in disease. Here, we leverage data from human and mouse models to perform a cross-species analysis of macrophage responses to Mtb. Overall, we find that both subsets of human and murine macrophages mount a strong interferon response to Mtb infection. However, AMs across both species do not generate as strong a pro-inflammatory response as human MDMs or murine bone marrow-derived macrophages (BMDMs), as characterized by TNFA signaling and inflammatory response pathways. Interestingly, AMs from mice that were previously vaccinated with BCG (scBCG) or from a model of contained TB (coMtb) had more similar responses to human AMs than control mice. We also identify species-specific pathways altered by infection differently in mouse and human macrophages, including cholesterol homeostasis. Lastly, to investigate downstream effects of the macrophage interferon responses, we examine expression of interleukin (IL)-10, an immunosuppressive cytokine induced by Type I Interferons, and c-Maf, a transcription factor required for myeloid IL-10 expression. We find that c-Maf and IL-10 have significantly lower expression in AMs compared to MDMs in both humans and mice, suggesting one possible mechanism by which AMs mount a stronger interferon response following Mtb infection. Overall, these results highlight the dynamics of innate myeloid responses throughout Mtb infection and the benefit of a combined analysis across species to reveal conserved and unique responses.

The generation and function of effector and memory CD8+ T cells are crucial for effective immune responses and long-term immunity. Using gene expression analysis, we found that doublesex- and mab-3-related transcription factor like family A1 (Dmrta1), a member of the DMRT family of transcription factors, is highly expressed in activated and memory CD8+ T cells. In this study, we investigated the role of Dmrta1 in the activation and differentiation of CD8+ T cells. The Dmrta1-deficient (Dmrta1-KO) mice showed an equivalent number of thymic and splenic T cells compared with wild-type mice. Dmrta1 deficiency in T cells resulted in impaired early activation of CD8+ but not CD4+ T cells and reduced expression of granzyme B in CD8+ T cells following influenza virus infection. Although virus-specific CD8+ T cell numbers and cytotoxicity in the lung were comparable between wild-type and Dmrta1-deficient mice during primary infection, Dmrta1-KO mice exhibited a transient accumulation of virus-specific CD8+ T cells in the spleen with reduced cytotoxic activity. Upon secondary challenge, memory CD8+ T cells from Dmrta1-KO mice showed persistent defects in granzyme B expression and cytotoxic function. These findings demonstrate that Dmrta1 modulates the early activation of naïve CD8+ T cells and supports the cytotoxic functionality of both effector and memory CD8+ T cells, particularly in secondary lymphoid organs, with significant implications for antiviral immunity.

The IL-1 family of cytokines produced by antigen-presenting cells plays important roles in various diseases and infections, including Mycobacterium tuberculosis (Mtb) infection. In the present study, we infected human monocyte-derived macrophages (MDMs) with Mtb. Then, we measured the production of IL-1 superfamily (ILSF) cytokines (8 soluble factors) and determined the effects of ILSF cytokines on Mtb growth via the use of recombinant cytokines and antibodies. Mtb infection significantly increased the production of IL-1α, IL-1β, IL-18, and IL-37 and reduced the production of IL-1Ra by MDMs. Human recombinant IL-1α, IL-1β, and IL-18 reduced Mtb growth in MDMs. In contrast, human recombinant IL-1Ra enhanced Mtb growth in MDMs. Neutralizing antibodies against IL-1α, IL-1β, and IL-18 enhanced Mtb growth, and neutralizing antibodies against IL-1Ra and IL-33R reduced Mtb growth in MDMs. B cells are known to regulate inflammation in tuberculosis (TB) granulomas. We also determined the effects of B and NK cells on ILSF cytokine production by human monocytes. Furthermore, we determined the effect of B cells on Mtb growth in human monocytes. B cells significantly reduced IL-1α, IL-1β, IL-6, and TNF-α production; enhanced IL-1Ra, IL-18, and IL-10 production; and inhibited Mtb growth in human CD14+ monocytes. These findings may be relevant in human TB granulomas, where B cells may regulate the balance of proinflammatory and anti-inflammatory ILSF cytokines and inhibit TB growth.

Autoreactive B cell activity defines the earliest detectable stage (Stage 1) of type 1 diabetes (T1D) but is incompletely understood, particularly for B cells reactive against the key T1D autoantigen, insulin. To test whether Stage 1 T1D B cells are transcriptionally rewired compared to healthy individuals, we performed single-cell transcriptional, phenotypic, and immune repertoire profiling of CD19+ cells isolated from the peripheral blood of Stage 1 T1D individuals, identified via Type 1 Diabetes TrialNet as being positive for ≥ 2/5 islet autoantibodies, and healthy controls. Stage 1 T1D memory B cells upregulated n = 122 genes compared to healthy controls, including genes involved in actin cytoskeleton rearrangement, B cell receptor (BCR) signaling, and antigen presentation, and exhibited reduced BCR somatic hypermutation, particularly in atypical-like memory B cells. Clonally expanded B cells in the atypical-like memory subset of Stage 1 T1D individuals exhibited avidity driven insulin-binding specificities, without polyreactivity to HEp-2 cell autoantigens. Insulin-binding B cells showed non-significant upregulation of genes involved in key B cell functions. Our findings highlight transcriptional and BCR-repertoire differences in Stage 1 T1D B cells with potential for optimization as future screening tools to identify rare, autoreactive B cells and biomarkers of T1D progression.