The CD40L molecule is primarily expressed on the activated CD4+ T lymphocytes and plays a key role in the immune response. Upon contact with a B lymphocyte, CD40L binds to the CD40 receptor and triggers signaling pathways, leading to B cell proliferation and differentiation and inducing a switch in Ig synthesis. When using soluble forms of CD40L as an activator, preliminary forced multimerization of CD40L is a prerequisite. A construct in which the receptor-binding domain of CD40L is fused to the collagen-like domain of adiponectin (Adn) is often used to multimerize CD40L. It is believed that Adn-CD40L forms several oligomeric forms. In our study, we obtained an Adn-CD40L preparation from which we isolated the low-molecular-weight and high-molecular-weight forms of Adn-CD40L (LMW and HMW). We next studied their biochemical, structural, and functional characteristics. It was concluded that LMW is a trimer of Adn-CD40L, while HMW is a mixture of higher-order oligomers. LMW demonstrated higher activity in the NF-κB-dependent signaling pathway activation assays compared to HMW. However, HMW induced more pronounced B-cell expansion and stimulated Ig secretion to a greater extent than LMW. These results could be used to develop new CD40L-based immunotherapeutics.

Regulatory T cells (Tregs) control immune responses to autoantigens and play a key role in suppressing autoimmune reactions during the development of autoimmune diseases. One of the approaches to personalized regenerative therapy for autoimmune diseases is enhancing the proliferative and suppressive activities of Tregs ex vivo. The transcription factor Forkhead box protein P3 (FoxP3) is a key regulator of the proliferative and suppressive activities of Tregs. FoxP3 pre-mRNA undergoes alternative splicing, and the full-length splice variant stimulates Treg proliferation and suppressive activity. In this study, we used cells obtained from three healthy donors and three patients with multiple sclerosis to compared the levels of FoxP3 splice variants in Tregs during their ex vivo expansion (expanded Tregs, eTregs) and Tregs generated by transformation of CD4+ T cells (transformed Tregs, tTregs). The full-length FoxP3 splice variant predominated in tTregs during the transformation process, which was accompanied by the increased proliferative and suppressive activities of these cells. In contrast, ex vivo expansion of eTregs did not alter the proportions of FoxP3 splice variants; these cells proliferated less actively and exhibited lower suppressive activity than tTregs. Our findings demonstrate that transformation of CD4+ T cells into Tregs is accompanied by an increase in the proportion of the full-length FoxP3 splice variant. Therefore, transformation may represent a more effective strategy than expansion of mature Tregs for generation of highly proliferative and suppressive cells in regenerative medicine.

Novel anti-CD20 monoclonal antibodies have been developed to optimize B-cell depletion. A key mechanism of action of these therapeutic monoclonal antibodies is the activation of immune cells via Fc receptors (FcγR). B-cell depletion with anti-CD20 monoclonal antibodies was initially developed for the treatment of B-cell lymphoma. Subsequently, its use was extended to autoimmune diseases. Rituximab has long been the main monoclonal antibody used to treat immune-mediated glomerulopathies. In glomerular diseases, rituximab was initially used to treat membranous nephropathy, demonstrating a better safety profile compared to conventional immunosuppressive therapies and a good treatment response. Therefore, other drugs targeting the same therapeutic receptor, anti-CD20, have been developed. This review aims to highlight, from a comprehensive perspective, the different anti-CD20 agents available to date.

Members of the nuclear receptor subfamily 2, group C (NR2Cs), despite sharing structural homology with established biomarkers like estrogen receptor (ER), progesterone receptor (PR), and androgen receptor (AR), remain underexplored in breast cancer (BC). This study aims to elucidate the subtype-specific prognostic significance of NR2Cs and investigate the molecular and immunomodulatory mechanisms of NR2C2 in restricting BC progression. We integrated transcriptomic data from TCGA with functional genomics to analyze NR2Cs expression and patient prognosis. Mechanistic landscapes were characterized using pathway enrichment, protein-protein interaction networks, immune infiltration algorithms, and pharmacogenomic drug sensitivity correlation. In vitro validation was performed using cell proliferation, colony formation, 5-Ethynyl-2'-deoxyuridine (EdU), and wound healing assays. In vivo antitumor efficacy and T-cell infiltration levels were evaluated using orthotopic human MDA-MB-231 xenografts in BALB/c nude mice and syngeneic murine EO771 tumors in immunocompetent C57BL/6 mice, supplemented by multiplexed immunohistochemistry. Both NR2C1 and NR2C2 were significantly downregulated in BC tissues compared with normal controls. NR2C2 demonstrated a robust, pan-subtype protective profile, correlating with prolonged survival across major molecular subtypes, particularly in ER-positive cohorts. In silico profiling connected NR2C2 to transforming growth factor-β (TGF-β) pathway inhibition and tumor-immune T-cell infiltration enhancement. In vitro, NR2C2 overexpression significantly suppressed BC cell proliferation, colony formation, DNA synthesis, and migratory capabilities. In vivo, NR2C2 overexpression markedly restricted tumor growth in both models. Mechanistically, this tumor-suppressive effect was characterized by cell-intrinsic growth arrest (decreased Ki-67), induced apoptosis (increased Cleaved Caspase-3), and significant inhibition of the TGF-β pathway (decreased Smad). Concurrently, in the immunocompetent syngeneic model, Nr2c2 overexpression promoted a robust recruitment of infiltrating CD4[+] and cytotoxic CD8[+] T cells into the tumor microenvironment. Our findings establish NR2C2 as a pivotal tumor suppressor in BC that restrains tumor progression by attenuating TGF-β signaling, thereby simultaneously suppressing cell-intrinsic proliferation and promoting T-cell infiltration into the tumor microenvironment. This study offers a promising therapeutic paradigm bridging orphan nuclear receptor biology with active cancer immunotherapy.

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by a remarkably broad and heterogeneous autoantigen repertoire. While epitope spreading, aberrant B-cell activation, and molecular mimicry act in concert with defective apoptotic clearance and sustained type I interferon signaling to drive systemic autoreactivity, many clinical manifestations of the disease are highly localized. The involvement of neuropsychiatric, renal, cutaneous, pulmonary, vascular, and hepatic systems appears to be shaped by tissue-specific autoantigen exposure and local microenvironments, where shared immunopathogenic pathways give rise to organ-associated autoantigenic landscapes. This review develops the concept of organ-associated autoantigenic landscapes, defined here as context-dependent configurations in which autoantibody-autoantigen interactions intersect with regional microenvironments and may contribute to inflammatory cascades, complement activation, and cellular damage. Importantly, organ association does not imply strict organ specificity, as the same circulating autoantibody may acquire distinct clinical relevance across tissues depending on antigen accessibility and local effector conditions. By illustrating how specific autoantibody-autoantigen axes may translate systemic autoimmunity into restricted clinical patterns, this framework provides a unifying model for disease heterogeneity and supports the development of precision, antigen-targeted therapeutic strategies.

The rapid evolution of SARS-CoV-2 and the ongoing risk of zoonotic spillover highlight the need for vaccines that provide broad protection beyond strain-specific immunity. Here, we present a structure-guided, AI-enabled strategy for rational antigen design that enhances cross-reactive B-cell epitope recognition across betacoronaviruses. By integrating comparative sequence analysis with conformational epitope prediction, we identified conserved epitope hotspots within the Spike receptor-binding domain and introduced targeted motif-level substitutions into a SARS-CoV-2 BA.2 backbone. Engineered Spike immunogens, delivered as mRNA-lipid nanoparticle vaccines, elicited robust antibody responses in mice and demonstrated broad neutralizing activity against antigenically diverse SARS-CoV-2 variants, including BA.5 and XBB.1.5, as well as zoonotic sarbecoviruses. Selected designs reached neutralisation breadth comparable to an Omicron-adapted clinical benchmark for shared SARS-CoV-2 antigens, while extending neutralising activity to divergent zoonotic sarbecoviruses. These findings show that minimal, structure-guided epitope remodeling can enhance the presentation of conserved epitopes and improve antibody breadth, providing a generalizable framework for designing vaccines resilient to viral evolution and future pandemic threats.

Splenic senescence represents a hallmark of aging-related immune dysfunction, and the fungus Kazachstania pintolopesii is capable of aggravating senescence-associated phenotypes in aged mice. As a natural bioactive ingredient, Astragaloside IV (AGS) possesses anti-aging and immunomodulatory capacities, whereas its protective mechanisms against K. pintolopesii-triggered splenic senescence remain poorly defined. This study aimed to clarify the molecular mechanisms underlying K. pintolopesii-induced splenic senescence and validate the protective efficacy of AGS.

HIV transmission from one individual to another occurs by one or a small number of virions followed by spread and genetic diversification into a complex quasispecies. To understand the early events in this process, we investigated how HIV-1 genomes diversify within the first two to three weeks after transmission by use of ultra-deep single subgenomic sequencing of over 10,000 plasma RNA genomes in each of a cohort of 15 individuals in acute infection. This approach confirmed transmission of one or a few transmitted/founder (TF) viral lineages and very limited early divergence from the founder sequences. Most observed variants that differed from the TF included single nucleotide changes attributable to HIV-1 reverse transcriptase (RT) error or host APOBEC3G/F activity. Comparing the number of expected versus observed changes after transmission indicated that most de novo mutations do not persist in the virus population, consistent with strong purifying selection. We found little evidence that early diversification is driven by reversions to subtype consensus or by cytotoxic T lymphocyte pressure, although rare multi-mutation lineages suggest occasional influences. Together, these findings indicate that early HIV-1 evolution is influenced by stochastic and host-mediated mutational processes (e.g. , APOBEC3G/F) filtered by strong purifying selection. The strong purifying selection observed in the early weeks of HIV-1 infection may provide an opportunity to investigate the potential of new interventions to induce viremic control, such as combinations of broadly neutralizing antibodies, cellular immunotherapy, or mRNA therapeutic vaccination.

Klebsiella michiganensis, an emerging multidrug-resistant member of the Klebsiella oxytoca complex, has become an important opportunistic pathogen responsible for nosocomial infections, including bacteremia and ventilator-associated pneumonia. Owing to its rapidly evolving resistance to carbapenems, new preventive strategies are urgently needed. This study presents a computational systems immunology framework integrating subtractive proteomics, reverse vaccinology, and immunoinformatics to design a multi-epitope vaccine (MEV) against K. michiganensis strain ATCC 8724. From the complete proteome (5,483 proteins), four proteins associated with the bacterial envelope and LPS-related processes were prioritized as computational vaccine targets: the outer-membrane β-barrel proteins BamA and LptD, the periplasmic LPS transport component LptA, and the outer-membrane lipoprotein LolB. These were selected as non-homologous and antigenic candidates. Cytotoxic T-lymphocyte, helper T-lymphocyte, and B-cell epitopes derived from these proteins were evaluated for antigenicity, toxicity, allergenicity, and global HLA population coverage. The selected epitopes were assembled using AAY, GPGPG, and KK linkers with the Mycobacterium tuberculosis 50 S ribosomal protein L7/L12 as an adjuvant to construct a 386-amino-acid chimeric MEV. Structural modeling and refinement showed 95.6% residues in favored regions of the Ramachandran plot. Molecular docking with the TLR1 component (chain B) of the TLR1-TLR2 heterodimer predicted a favorable interaction (ΔG = - 14.8 kcal/mol), while a 100-ns molecular dynamics simulation suggested maintenance of the overall docked-complex architecture. C-ImmSim predicted increases in immunoglobulin and cytokine levels consistent with potential activation of humoral and cellular immunity. Codon optimization (CAI = 0.94, GC = 50%) supported predicted expression feasibility in E. coli. This computationally designed MEV represents a candidate for future experimental evaluation against K. michiganensis, requiring further experimental validation.

The immune response is essential in shaping bone healing outcomes and is of particular interest in mandible fractures, as opposed to other fractures, because of the presence of teeth that are colonised by a multitude of microbes that can cause infection or complicate healing. This study investigated the peripheral blood cell transcriptome during mandibular fracture healing phases with particular focus on immune-related indicators. Blood samples from mandibular fracture patients who had normal healing were collected at the time of injury, then 2 weeks and 6 weeks following the injury, corresponding to the inflammation, repair, and remodelling phases of bone healing, respectively. RNA sequencing was performed for blood cells and analysed using the Ingenuity Pathway Analysis (IPA) software. Data validation was conducted using ELISA for soluble serum factors and blood cell counting using Sysmex. The results indicated distinctive systemic changes between the three healing phases. A significant increase in activity and counts of blood neutrophils and monocytes was noted during the inflammatory and repair phases compared to the remodelling phase. In contrast, a prominent activity and increased quantity of lymphocytes were detected in the remodelling phase. Furthermore, increased serum levels and activated signalling of interleukin 10 (IL10) were detected at the systemic level, mainly during the inflammation and repair phases. Interestingly, blood cells were found to express high levels of osteogenesis-related markers during the repair phase, with significantly increased serum levels of Insulin-like growth factor 2 (IGF2). In conclusion, systemic blood cell transcriptomic profiling showed a shift from predominantly innate toward adaptive immune response during mandible healing, with serum IL10 and IGF2 levels indicating the resolution of inflammation and the start of osteogenic repair. Therefore, peripheral blood cells and serum factors could be a promising source of non-invasive biomarkers for monitoring healing trajectories of mandible injuries.

Celiac disease (CeD) is driven by pathogenic CD4[+] T cell responses, primarily targeting four HLA-DQ2.5-restricted immunodominant epitopes derived from α-gliadin and ω-gliadin. While gliadin-specific CD4[+] T cells have been investigated, how transcriptional and effector phenotypes in CeD vary across distinct epitope specificities remains unclear, as do the signature TCR motifs governing gliadin epitope specificity and cross-reactivity. Single-cell transcriptomic and TCR profiling of gliadin epitope-specific peripheral blood CD4[+] T cells from patients with CeD after gluten challenge revealed T cells with an activated TH1 effector, conventional regulatory T cell (Treg cell) or cytotoxic phenotypes across specificities, with no evidence of functional specialization driven by specific epitopes. Moreover, we identified core TCR motifs that dictate gliadin epitope specificity and cross-reactivity and elucidated the structural basis of their cognate pMHC recognition. These motifs enabled accurate prediction of gliadin specificity from unassigned TCRs. Collectively, these findings advance our understanding of immune responses in CeD and provide a foundation for tracking disease-relevant T cells.

Precise three-dimensional (3D) genome organization is crucial for regulating gene expression during development, yet its role in age-related transcriptional changes and physiological decline remains elusive. Here, we show that aging reshapes chromatin architecture and gene regulation in murine naive CD4[+] T cells, a quiescent T cell population essential for adaptive immunity. Aged naive CD4[+] T cells exhibit intrinsic transcriptional reprogramming marked by increased expression of inflammatory and T cell activation-related genes, rendering them more prone to activation. Intriguingly, these changes are accompanied by pronounced alterations in 3D genome organization, including widespread weakening of topologically associating domain (TAD) boundaries and extensive enhancer-promoter rewiring. Mechanistically, we demonstrate that these age-associated structural changes can be partly attributed to the diminished expression of chromatin organizer SATB1. SATB1 colocalizes with CCCTC-binding factor (CTCF) in young naive T cells to spatially constrain CTCF-binding sites. Its decline with age extends the range of CTCF-mediated interactions without altering CTCF occupancy, leading to remodeling of chromatin architecture and up-regulation of proinflammatory and proactivation genes. Conditional SATB1 deletion in naive T cells recapitulates the 3D genome and transcriptional changes observed in aging. Our findings reveal a critical role for SATB1 in maintaining 3D genome integrity in naive T cells and suggest that the dysregulation of genome architecture contributes to immune and organismal aging.