Search Results (1,987)

Colorectal cancer (CRC) is the third most commonly diagnosed malignancy worldwide, with molecular heterogeneity complicating early detection and treatment stratification. The insulin-like growth factor (IGF) axis interacts bidirectionally with immune regulatory mechanisms in ways that shape tumor phenotype and therapeutic vulnerability. This review synthesizes evidence on how IGF signaling orchestrates immunosuppression through effects on tumor-associated macrophages, regulatory T cells, and myeloid-derived suppressor cells, while inflammatory cytokines reciprocally modulate IGF bioavailability. Three mechanistic principles emerge: IGF binding protein 2 (IGFBP-2) functions as a central coordinator linking growth factor signaling to immune evasion through STAT3-dependent pathways driving M2 macrophage polarization and regulatory T cell differentiation; IGF–immune crosstalk varies considerably across molecular subtypes, with microsatellite-stable tumors exhibiting high reliance on IGF-I receptor-mediated immune silencing; and local paracrine IGF production increasingly dominates over systemic regulation as disease progresses. These bidirectional connections establish self-reinforcing circuits that determine whether tumors remain immunologically responsive or develop immune exclusion. Multi-marker panels incorporating IGFBP-2 alongside complementary biomarkers have shown improved diagnostic performances for early CRC detection, underscoring the need for the large-scale prospective clinical evaluation of IGF network components as biomarkers for CRC in diverse populations. The convergence of IGF signaling with checkpoint regulation suggests that combined targeting warrants investigation for resistance in tumors lacking effective immunotherapy options. Full article

Background/Objective: This study is a cross-sectional investigation of long-term immune responses measured at different time intervals after COVID-19 infections, vaccinations, or combined exposure. The focus is on immune reactivity against recombinant spike (S) and nucleocapsid (N) protein antigens. Materials and Methods: Serum antibody levels were assessed up to four to four and a half years after infection or immunization, including virus-specific immunoglobulin G (IgG), IgA and IgM antibodies, as well as neutralizing antibodies against the S-protein. Cellular immunity was assessed by analyzing peripheral blood mononuclear cells (PBMC; n = 43 in first cohort, n = 32 in second cohort), including T-helper memory and cytotoxic subsets, and cytokine production after in vitro stimulation with recombinant SARS-CoV-2 proteins. A multiplex cytokine assay was used to analyze effector and regulatory immune responses. Results: Virus-specific IgG antibodies persisted for years after exposure to SARS-CoV-2, with IgG against the receptor-binding domain (RBD) correlating most strongly with neutralizing activity. Vaccinated individuals demonstrated higher IgA responses, whereas antibodies to the N-protein were associated with previous infection. No IgM antibodies were detected in any subjects, suggesting an immune response based on memory rather than ongoing infection. PBMCs from individuals with a history of both COVID-19 exposure and vaccination exhibited enhanced responsiveness, characterized by increased frequencies of memory T cells compared to vaccination alone. Stimulating with the S-protein induces higher cytokine production, including IFN-gamma, TNF-alfa, and IL-12(p70), compared with stimulation by the N-protein. Cytokines such as IL-10 and TGF-beta are also elevated, suggesting immune regulation rather than persistent inflammation. Conclusions: SARS-CoV-2 infection and vaccination are associated with persistent humoral and cellular immune responses detectable several years after exposure. Individuals with hybrid immunity exhibit broader and functionally enhanced immune reactivity, indicating more robust long-term immune memory. Future studies should focus on the long-term consequences of hybrid immunity and optimize other vaccine strategies, including recombinant antigen vaccines. Full article

Respiratory infections remain a leading cause of morbidity and mortality worldwide, highlighting the urgent need to better understand host defense mechanisms in the respiratory tract. Recent advances in sequencing technologies have challenged the traditional view of the lungs as sterile organs and revealed the presence of a distinct, low-biomass microbial community known as the lung microbiota. These microbial populations interact closely with airway epithelial cells and immune cells to maintain respiratory homeostasis and regulate host immune responses. In healthy lungs, microbial communities dominated by Firmicutes, Bacteroidetes, and Proteobacteria contribute to immune regulation through interactions with innate and adaptive immune pathways. Microbiota-derived signals are detected by pattern recognition receptors, activating signaling pathways that regulate cytokine production, immune cell recruitment, and T-cell differentiation. In the respiratory mucosa, microbial stimulation can also induce epithelial and antigen-presenting cells to produce B-cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL), which promote immunoglobulin A (IgA) class-switch recombination and support mucosal antibody responses. During pulmonary infection, disruption of microbial communities can lead to dysbiosis that amplifies inflammatory responses, impairs epithelial barrier integrity, and increases susceptibility to secondary bacterial infections. In addition to local microbial interactions, the gut–lung axis represents a key communication pathway linking intestinal microbiota with respiratory immunity through microbial metabolites such as short-chain fatty acids (SCFAs) and immune signaling networks. This review summarizes current insights into microbiota–immune crosstalk in the lung during pulmonary infection and discusses how these interactions may inform mucosal vaccine development. A deeper understanding of host–microbiota interactions may enable microbiome-informed vaccines and therapeutic strategies to improve protection against respiratory diseases. Full article

Cirrhosis is no longer viewed solely as an isolated hepatic disorder but rather as a complex multisystemic disease that affects cardiovascular, renal, pulmonary, metabolic, and immune systems. One of its most clinically relevant but under-recognized consequences is cardiac dysfunction, manifesting as cirrhotic cardiomyopathy, portopulmonary hypertension, right ventricular (RV) failure, and impaired myocardial strain. Oxidative stress (OS) has recently emerged as a fundamental mechanistic link between hepatic fibrogenesis and myocardial remodeling, acting through mitochondrial injury, NADPH oxidase activation, nitric oxide dysregulation, iron-mediated ferroptosis, and inflammatory cytokines. These alterations lead to diastolic dysfunction, autonomic imbalance, myocardial fibrosis, electrophysiological abnormalities (including QTc prolongation), and impaired RV–pulmonary artery coupling. Redox biomarkers such as malondialdehyde (MDA), NOX2-derived peptides, GSH/GSSG ratio, sST2, NT-proBNP, and 8-isoprostanes hold promise in detecting early subclinical cardiac involvement in cirrhosis. Novel antioxidant therapies, including mitochondrial-targeted molecules, NOX inhibitors, and ferroptosis blockers, may improve myocardial remodeling and hemodynamic stability. This review explores the central role of redox imbalance in the cardiohepatic syndrome and its potential utility in diagnosis, monitoring, and therapy. Full article

Background and Objectives: Cutaneous melanoma (CM) is one of the most aggressive skin malignancies due to its rapid progression and high therapeutic resistance. Growing evidence demonstrates that the tumor microenvironment (TME)—comprising diverse immune, stromal, vascular, and epidermal cell populations alongside various cytokines and growth factors, as well as extracellular matrix (ECM) components—plays a crucial role in tumor heterogeneity, metastatic potential, and response to therapy. This review aims to synthesise current knowledge on the cellular and non-cellular constituents of the CM microenvironment and clarify their contributions to tumor progression, immune evasion, and treatment resistance. Materials and Methods: We conducted a narrative review of recent experimental, clinical, and translational studies investigating melanoma–microenvironment interactions, integrating evidence from in vitro, in vivo, and human tissue analyses. Results: Melanoma exhibits marked intra-tumoral heterogeneity driven by genetic, epigenetic, and microenvironmental influences. Cancer-associated fibroblasts, adipocytes, endothelial cells, and keratinocytes are reprogrammed by melanoma cells to promote invasion, angiogenesis, and metastasis. Immune subsets play divergent roles: neutrophils, M2 macrophages, myeloid-derived suppressor cells, and tolerogenic dendritic cells foster immune suppression, while lymphocytes—particularly CD8⁺ T cells, TFH cells, and B cells —are associated with improved outcomes but often become dysfunctional. ECM remodeling, including collagen deposition, integrin signaling, and increased matrix stiffness, actively remodels the tissue to support tumor growth and immune evasion. Hypoxia-inducible factor (HIF)-mediated signaling drives cell dedifferentiation, angiogenesis, and metabolic changes that contribute to treatment resistance. Consequently, emerging therapeutic strategies are moving beyond targeting tumor cells alone to focus on modulating TME components, counteracting immunosuppression, hypoxia, metabolic reprogramming, and extracellular vesicle signaling. Conclusions: The TME profoundly modulates tumor behavior and therapeutic response. A deeper understanding of the reciprocal interactions between melanoma cells and their microenvironmental components may enable the development of more effective strategies for early detection, prognosis, and personalized therapies. Full article

Background: Prostate cancer (PCa) arises from complex interactions among host genetics, androgen signaling, and microbial communities. Emerging genomic evidence supports the presence of microbial consortia within prostate tissue, suggesting that microbial genes, metabolites, and host–microbe interactions may contribute to chronic inflammation, oncogenic signaling, and therapeutic resistance. Methods: We conducted a narrative review using targeted searches of PubMed and Google Scholar for studies published between 2020 and 2025, complemented by selected mechanistic reports published in March 2026. Human studies and experimental research providing mechanistic insights into prostate models were prioritized. Due to the heterogeneous methodologies, evidence was synthesized qualitatively, with an emphasis on genomic and signaling perspectives. Results: Low-biomass microbial DNA is consistently detected in prostate tissue. Proteomic analyses of Corpora amylacea suggest a “fossil record” of past infections through sequestered microbial DNA and antimicrobial proteins, potentially priming tissue for long-term carcinogenic processes, although contamination remains a key limitation. Recurrent bacterial and viral signals, including Cutibacterium acnes, Escherichia coli, Pseudomonas, Acinetobacter, human papillomavirus, Epstein–Barr virus, and cytomegalovirus, appear to converge on a restricted set of tumor-relevant pathways, including TLR–NF-κB, MAPK, PI3K/AKT/mTOR, cGAS–STING, and p53/pRb disruption. These interactions may promote cytokine production, oxidative stress, DNA damage, epithelial–mesenchymal transition, extracellular matrix remodeling, immune evasion, and resistance to therapy. The gut–prostate axis further links intestinal dysbiosis and microbial metabolites with systemic IGF-1 signaling and castration resistance. Conclusions: Microbial genomic consortia in the prostate and gut may shape inflammatory, metabolic, and immune networks that influence PCa initiation and progression. However, most available data remain correlative and are limited by low-biomass sampling, contamination risk, and heterogeneous study designs. Future research should prioritize rigorous contamination control, longitudinal and prostate-specific mechanistic studies, and integrated multi-omic approaches to clarify causality and identify actionable microbial targets for prevention, diagnosis, and therapy. Full article

Inflammation is associated with metabolic alterations that can lead to the release of volatile organic compounds (VOCs) reflecting cellular biochemical activity. Profiling these volatile metabolites may provide insight into cellular responses to inflammatory stimuli, although their characterization in skin-derived cells remains limited. In this exploratory proof-of-concept study, we investigated the volatile metabolite profiles of human skin fibroblasts exposed to different inflammatory stimuli. Fibroblast cell lines were stimulated with polyinosinic:polycytidylic acid (Poly I:C), tumor necrosis factor-alpha (TNF-α), and lipopolysaccharide (LPS) to model viral-, cytokine-, and bacterial-associated stress conditions. Headspace solid-phase microextraction coupled with comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry (HS-SPME-GC×GC-TOFMS) was applied to analyze volatile metabolites released from the cell cultures, enabling exploratory profiling of the fibroblast volatilome. A data-processing workflow including pairwise comparisons between experimental groups and statistical filtering was implemented to identify volatile features associated with the different conditions. Several VOCs were tentatively identified, mainly belonging to alcohol, ester, and hydrocarbon classes, and showed differential abundance patterns between stimulated and control samples. Multivariate analysis indicated a separation between stimulated and non-stimulated groups, suggesting stimulus-associated differences in the volatile profiles of fibroblast cultures. While these observations may reflect metabolic responses occurring under inflammatory stimulation, the chemical identity and biochemical origins of several detected features remain to be confirmed. All in all, this study demonstrates the feasibility of applying HS-SPME-GC×GC-TOFMS-based volatilome profiling to investigate stimulus-associated changes in fibroblast cultures. The detected VOC patterns should therefore be considered preliminary observations requiring further chemical characterization and independent validation. Future studies including larger sample numbers, complementary biological verification of the inflammatory response, and more physiologically relevant experimental models will be necessary to further assess the robustness and potential relevance of these volatile signatures in the context of inflammatory processes. Full article

Objective: The purpose of this study was to determine the biological association between host-derived HSP47 and fungal-derived HSP90 in the context of vulvovaginal candidiasis (VVC) and to examine their relationships with clinical, inflammatory, and metabolic phenotypes in infected and healthy women. Methods: This study followed a six-month case–control design (February–July 2025) and was conducted at the University of Tabuk Hospital in Tabuk, Saudi Arabia. A total of 84 women aged 18–45 years were recruited, of which 42 were VVC-infected, and 42 were healthy controls. ELISA kits were used to test vaginal swabs for HSP47 and HSP90. Clinical, hematological, cytokine, and metabolic markers were also evaluated. Mann–Whitney U, Spearman correlation, and multiple linear regression tests were performed to analyze the data. Results: The levels of HSP47 and HSP90 were significantly higher among infected patients (2.29 ng/mL and 3341 ng/mL, respectively) when compared with controls (0.58 ng/mL and 1025.7 ng/mL; p < 0.001). Women who were infected were older (p = 0.02), but there were no significant differences in terms of BMI (p = 0.29). The levels of vitamin D and adiponectin were significantly decreased (p < 0.001), while pro-inflammatory cytokines (IL-6, TNF-α, IFN-γ, TGF-β, and IL-8) and WBC counts were higher compared to the control group. The hematology results were characterized by inflammation-related anemia and disturbed protein metabolism. The ROC analysis demonstrated good diagnostic performance, with an AUC of 1.0 in the case of HSP47 and 0.905 in the case of HSP90. In the case of the infected patients, the regression models were found to be weak (HSP90 R² = 0.154; HSP47 R² = 0.273), although HSP47 retained significant connections with IL-8 (p = 0.005) and IFN-γ (p = 0.028). Conclusions: High levels of HSP47 and HSP90 are observed in VVC, reflecting an epithelial stress response and fungal persistence. These HSPs have high diagnostic accuracy, which justifies their potential as biomarkers for the timely detection of VVC; they also have further implications as early biomarkers for prognostic and treatment monitoring support, despite the poor predictive models. This study has some limitations that must be addressed; in particular, the regression analyses failed to provide statistically significant predictive models, likely due to the limited sample size. In addition, the specificity of HSP90 and HSP47 for VVC in comparison with other vaginal infections was not evaluated. Full article

Type 1 diabetes (T1D) is an immune-mediated disease characterized by progressive autoimmune destruction of pancreatic β cells. Although traditionally viewed as primarily T-cell-driven, B cells play essential roles in disease pathogenesis. In addition to producing islet autoantibodies, B cells contribute to immune activation through antigen presentation and cytokine secretion, thereby shaping autoreactive T-cell responses. The earliest clinical predictor of T1D is the appearance of islet autoantibodies in the blood, reflecting a breach in B-cell tolerance well before symptomatic disease onset. In individuals at high genetic risk, type I interferon (IFN) signatures are detectable in peripheral blood prior to seroconversion, suggesting that type I IFNs may act as upstream regulators of B-cell tolerance. Peripheral tolerance is enforced through layered checkpoints including transitional selection, maintenance of anergy, germinal center regulation, and regulatory B-cell differentiation. Studies in systemic autoimmunity demonstrate that type I IFN signaling lowers B-cell activation thresholds, enhances BCR and TLR responsiveness, promotes survival of autoreactive transitional clones via BAFF induction, destabilizes anergy, and skews differentiation toward inflammatory phenotypes such as T-bet+ age-associated B cells. Consistent with this model, single-cell transcriptomic and BCR repertoire analyses in T1D reveal clonal expansion and proinflammatory signatures in islet-reactive B cells during the preclinical stage. Together, these findings implicate the IFN–B-cell axis as a potential target for early disease modification. Full article

Background/Objectives: Sporotrichosis is an emerging zoonotic subcutaneous fungal infection with limited therapeutic options, highlighting the need for improved immunomodulatory strategies. CTLA-4 is an inhibitory immune checkpoint that negatively regulates T-cell activation. In this study, we evaluated whether a CTLA-4 antisense oligonucleotide (CTLA-4 ASO) is associated with enhanced immune responses to an adjuvanted recombinant Sporothrix sp. enolase antigen (rSsEno) formulation. Methods: CTLA-4 ASO uptake, cytotoxicity, and gene-silencing activity were assessed in murine splenocytes in vitro. BALB/c mice were immunized with rSsEno formulated with Montanide Gel 01, either alone or in combination with 5 µg CTLA-4 ASO. Antigen-specific serum antibody responses were quantified by ELISA. Splenocytes from immunized mice were restimulated with enolase, and cytokine production (IFN-γ, IL-2, IL-17, and TNF-α) was measured using Cytometric Bead Array (CBA). Results: CTLA-4 ASO was efficiently internalized by splenocytes and was associated with reduced expression of CTLA-4 without detectable cytotoxicity in vitro. Mice receiving the ASO-supplemented formulation developed significantly higher anti-enolase antibody titers compared to those immunized with adjuvant alone. Upon antigen restimulation, splenocytes from ASO-treated mice produced higher levels of IFN-γ, IL-2, TNF-α, and IL-17, consistent with an enhanced recall response characterized by a mixed Th1/Th17 cytokine profile. Conclusions: CTLA-4 ASO was associated with an enhanced recall response characterized by a mixed Th1/Th17 cytokine profile. These findings suggest a potential immunomodulatory effect of CTLA-4 targeting. Further studies incorporating dose optimization, infection challenge models, and appropriate sequence controls are required to determine the specificity and relevance of these effects for protective immunity against sporotrichosis. Full article

Lipopolysaccharide-induced tumor necrosis factor alpha factor (LITAF) as a crucial cytokine can mediate the inflammatory and immune regulatory responses of an organism. It plays a significant mediatory role in the innate immune system of insects. Firstly, the LITAF family of cotton bollworm (Helicoverpa armigera, Lepidoptera: Noctuidae) was analyzed, and the differentially expressed genes of HaLITAFs were screened from the 2-tridecanone-treated transcriptome. Subsequently, these two differentially expressed HaLITAF genes were cloned and analyzed, and the effect of different larval stages, tissues, and plant secondary metabolites on their gene expression were detected in H. armigera. The cotton bollworm contains 13 LITAF genes, and there are no repetitive sequences among them. Upon 2-tridecanone treatment, only HaLITAF5 and HaLITAF7 were significantly upregulated in the LITAF family of cotton bollworm larvae after 6 h. The HaLITAF5 and HaLITAF7 proteins, respectively, comprised 78 and 113 amino acids, and both contained a CXXC motif, hydrophobic amino acid region and HXCPXCXXXXG motif. Both of them belong to the LITAF analogues (zf-LITAF-like) superfamily. The expressions of HaLITAF5 and HaLITAF7 were both the lowest in fourth-instar larvae and the highest in sixth-instar larvae, and both were abundantly expressed in the midgut of sixth-instar larvae. Following a 28 h treatment with 2-tridecanone, the expression levels of HaLITAF5 and HaLITAF7 peaked. HaLITAF7 exhibited the highest expression level after a 4 h exposure to tannic acid, whereas HaLITAF5 reached its peak after 28 h of tannic acid treatment. The maximum expression levels of HaLITAF5 and HaLITAF7 were observed after 28 h and 4 h of quercetin treatment, respectively. Subsequent to ZQ-8 treatment, HaLITAF5 expression peaked at 28 h, while HaLITAF7 expression peaked at 8 h. Both HaLITAF5 and HaLITAF7 were overexpressed after different kinds of plant secondary metabolite stresses, and thereby, they may be regulated in the expression of genes related to downstream detoxification metabolic processes. This provides a theoretical foundation for further studies on the functional mechanism of the LITAF gene in H. armigera. Full article

Background/Objectives: The frequent use of antibiotics has led to increasing drug resistance in Aeromonas hydrophila; therefore, there is an urgent need to develop novel antimicrobial agents to prevent and control bacterial diseases in aquaculture. Allicin E (ALE) is derived from garlic (Allium sativum L.), a plant extensively used in traditional medicine for treating infections. This study aimed to evaluate the potential of ALE against A. hydrophila, a major aquaculture pathogen, by investigating its antibacterial efficacy, mechanisms of action, and in vivo protective effects. Methods: The minimum inhibitory and bactericidal concentrations (MIC/MBC) were determined by broth microdilution. Antibacterial mechanisms were investigated through ROS detection, electron microscopy, fluorescent staining, and content leakage measurement. In vivo efficacy was evaluated in Carassius auratus gibelio by monitoring survival rates and bacterial loads, analyzing immune and antioxidant biomarkers, and histopathological analysis after A. hydrophila challenge. Results: ALE exhibited potent antibacterial activity (MIC = MBC = 8 μg/mL), achieving complete bacterial elimination within 1 h and showing a low resistance propensity. Mechanistically, ALE induced ROS accumulation, causing oxidative damage that disrupted membrane integrity and facilitated the leakage of cellular contents. In vivo, ALE significantly enhanced fish survival, reduced bacterial loads, modulated inflammatory cytokines, boosted antioxidant enzyme activities (SOD and CAT), and alleviated tissue damage. Conclusions: ALE possesses potent in vitro antibacterial activity and exerts an inhibitory effect on bacteria-induced inflammatory responses, effectively combating A. hydrophila through a multi-target mechanism and enhancing host resistance. Full article

Background/Objectives: Ulcerative colitis (UC) involves inflammatory response, oxidative stress, changes in metabolites, and the gut microbiota. Jingangteng capsule (JGTC) has been utilized clinically for the treatment of inflammatory diseases for many years. However, the efficacy of JGTC in ameliorating UC remains unclear, and the underlying mechanisms have not yet been elucidated. This study aims to investigate the effect and mechanism of JGTC on UC. Methods: The chemical compositions of JGTC were examined using ultra-high-performance liquid chromatography with quadrupole time-of-fight mass spectrometry. The anti-UC effect of JGTC was evaluated by assessing the disease activity index (DAI), colon length, intestinal barrier recovery, and inflammatory factors in a dextran sulfate sodium (DSS)-induced colitis model. Mechanisms were investigated through fecal 16S rDNA sequencing, metabolomics analysis, enzyme-linked immunosorbent assay (ELISA), Western blotting, and network pharmacology analysis. Results: JGTC significantly reduced the DAI scores in UC mice, increased their body weight and colon length (p < 0.001), repairing damaged intestinal tissue. It decreased the levels of inflammatory cytokines TNF-α, IL-6, IL-1β, and LPS (p < 0.01, p < 0.001), alleviating intestinal inflammation. It also raised the expression of tight junction proteins ZO-1, Claudin-1, and Occludin (p < 0.05, p < 0.001), thereby enhancing intestinal barrier function. Fecal metabolomic analysis revealed that the favorable alterations in amino acid and lipid metabolites were more pronounced. Heat maps showed strong correlations between pharmacological indicators and gut microbiota, as well as between the main differential metabolites and gut microbial communities. UPLC-QTOF-MS detection yielded 33 components of JGTC, and network pharmacology analysis based on these components predicted pathways of action of JGTC in UC. Functional pathways closely associated with significantly differential metabolites and metabolic pathways were also investigated. The PI3K-AKT-mTOR pathway was one of them, which is consistent with the conclusions drawn from network pharmacology. JGTC significantly modulated key factors in this pathway, inhibiting the expression of PI3K, Akt, PDK1, and mTOR, while augmenting the expression of PTEN (p < 0.05, p < 0.01, p < 0.001). It also mitigated the levels of related oxidative stress factors MDA, MPO, and D-LA, and raised SOD levels (p < 0.01, p < 0.001). Conclusions: JGTC improved the excessive inflammatory response in UC by regulating intestinal flora and metabolic disorders, affecting the PI3K-AKT-mTOR signaling pathway, restoring intestinal tissue damage and intestinal barrier, and inhibiting inflammatory and oxidative stress factors. Full article

Background/Objectives: Tuberculosis (TB) remains a major global health challenge, requiring standardized animal models to evaluate vaccine-induced immune responses. This study characterized time-dependent immune responses following Bacillus Calmette–Guérin (BCG) vaccination in BALB/c mice. Methods: BALB/c mice were vaccinated with BCG, and the immune responses and protective efficacy were evaluated at 4, 6, and 8 weeks post-immunization. The cytokine expression in serum, lung, and spleen tissues was analyzed using ELISA, quantitative PCR, and immunohistochemistry. Protective efficacy was assessed via colony-forming unit (CFU) enumeration and the immunohistochemical detection of Mycobacterium TB after aerosol challenge. Results: The BCG vaccination induced time-dependent and tissue-specific cytokine responses. Pulmonary IL-1β and splenic IFN-γ levels were significantly increased four weeks post-vaccination. At 8 weeks, serum IL-2, pulmonary IL-2, and TNF-α were significantly increased, whereas no significant changes in cytokines were observed at 6 weeks. After the challenge, BCG-vaccinated mice exhibited reduced bacterial burdens compared with controls, but the differences among the 4-, 6-, and 8-week groups were modest. Conclusions: Immune responses became detectable starting four weeks after BCG vaccination, with temporal differences observed in cytokine expression. Week 8 may serve as a reference point for monitoring cytokine dynamics rather than as an optimal time for protection. Full article

Background: Renal allograft rejection remains a major challenge in transplantation. Current diagnostic approaches, including biopsies, are invasive and may fail to detect subclinical immune activation, potentially contributing to progressive graft dysfunction. Reliable, non-invasive biomarkers capable of monitoring immune activation and distinguishing rejection phenotypes are therefore needed. Methods: In this retrospective study, we evaluated serum neopterin as a biomarker of immune activation and graft status over 12 months following transplantation. Associations between neopterin levels and immune parameters, including natural killer (NK)-to-CD3⁺CD16/CD56⁺ T cell ratios, cytokines (IFN-γ and IL-10), and CD4⁺CD25⁺FoxP3⁺ T cell frequencies, were assessed. A total of 211 first renal allograft recipients were followed longitudinally, including patients with acute rejection (AR) and matched stable graft (SG) recipients. Serum neopterin was quantified by enzyme immunoassay, and immunophenotyping, mRNA expression, and cytokine profiling were performed on peripheral blood samples. Results: Serum neopterin levels were significantly elevated in AR compared to SG recipients, with a threshold of 57 nmol/L distinguishing AR with 81% sensitivity and 80% specificity. While IFN-γ demonstrated higher diagnostic performance in cross-sectional analysis, neopterin showed a more sustained elevation over time, remaining increased in AR recipients even at later post-transplant time points. Neopterin correlated positively with IFN-γ, but not IL-10, and inversely with CD4⁺CD25⁺FoxP3⁺ T cell frequency. NK cells were enriched during rejection, whereas CD3⁺CD16/CD56⁺ T cells were more prominent in graft stability. The NK-to-CD3⁺CD16/CD56⁺ T cell ratio was highest during acute cellular rejection. Conclusions: Neopterin reflects Th1-associated immune activation in renal allograft recipients and provides a temporally stable, non-invasive marker of immune status. Although it does not outperform IFN-γ levels at the time of rejection, its stability and sustained elevation suggest a complementary role in longitudinal monitoring. Integration of neopterin with immune parameters, including cytokine profiles and cellular subsets, may enhance the assessment of graft immunological status and support clinical decision-making. Full article