The initiation of adaptive immune responses relies on the precise recognition and interpretation of antigenic information. In this process, the specific binding of T cell receptors (TCRs) to peptide-major histocompatibility complex (pMHC) molecules represents one of the key molecular events in the initiation of adaptive immune responses. Accordingly, the structural features of TCR-pMHC complexes provide a fundamental basis for dissecting antigen recognition mechanisms and support rational vaccine design, therapeutic target discovery in TCR-based immunotherapy, and TCR identification and optimization. However, experimental determination of TCR-pMHC structures remains costly, time-consuming, and limited in coverage, making computational approaches essential for rapidly obtaining reliable structural information. Computational methods for predicting the structures of TCR-pMHC complexes have advanced rapidly in recent years, driven by progress in deep learning-based modeling frameworks and the increasing availability of structural and sequence resources. Despite these developments, most existing tools do not adequately distinguish the key structural and biophysical differences between MHC class I (MHC-I) and MHC class II (MHC-II) complexes during model construction. As a consequence, their predictive performance differs substantially between class I and class II complexes. In general, structural predictions for class I complexes outperform those for class II complexes. This discrepancy may be related to several fundamental differences between the two systems, including the architecture of the peptide-binding groove, the distribution of peptide lengths, and the properties of peptide flanking residues (PFRs). Compared with MHC-I molecules, MHC-II molecules usually bind longer antigenic peptides, which typically range from 13 to 25 amino acids in length. PFRs at both termini of these peptides participate in regulating the overall conformation of TCR-pMHC class II complexes and exert a pronounced effect on the geometric and physicochemical characteristics of the TCR-pMHC binding interface. Furthermore, within the TCR recognition interface, the complementarity-determining regions (CDRs) consist of segments that differ markedly in conformational behavior. They commonly include regions that are relatively rigid and structurally stable, together with highly flexible segments exhibiting substantial conformational plasticity. These rigidity-flexibility features constitute an essential structural basis enabling TCRs to recognize diverse peptide-MHC ligands and to accommodate conformational heterogeneity at the interface. However, many current modeling tools, in an effort to enforce global conformational stability or reduce structural noise, tend to over-constrain intrinsically flexible regions. Such oversimplification may lead to inappropriate rigidification of flexible CDR loops, resulting in local structural distortions, compromised interface geometry, or even complete modeling failure for specific complexes. Against this background, the review approaches the field from the perspective of computational differences between MHC-I and MHC-II complexes. We first systematically organize and summarize available resources related to TCRs and pMHCs, including structural datasets, sequence databases, prediction tools, and benchmarking studies. We then focus on five representative tools capable of predicting both class I and class II complexes—AlphaFold2, AlphaFold3, TCRmodel2, tFold-TCR, and TCR-pHLA_ModellerS. After excluding structures present in the training sets of these tools, we constructed a benchmark dataset comprising 25 class I and 10 class II TCR-pMHC complexes in the bound state and conducted a systematic evaluation using this dataset. We first employ widely used general evaluation metrics, including All-Atom Root Mean Square Deviation (All-Atom RMSD), Backbone RMSD, Template Modeling score (TM-score), and DockQ, to assess the global conformational accuracy and interface modeling quality of class I and class II complexes. For class II complexes, we propose for the first time a peptide flanking residue deviation index, including the PFRs-Deviation Index (PFRs-DI), N-PFR-Deviation Index (N-PFR-DI), and C-PFR-Deviation Index (C-PFR-DI), to quantitatively characterize conformational deviations in PFRs. In addition, we propose the CDR conformational consistency index (CCC) designed to qualitatively evaluate the ability of prediction tools to capture TCR CDR conformational flexibility. These metrics collectively assess a tool’s ability to model both overall conformation and critical functional regions, thereby addressing the limitations of existing evaluation criteria that overemphasize global structure while inadequately capturing modeling quality in key functional areas. This establishes a unified analytical framework for MHC-I and MHC-II complexes to guide data resource selection, modeling strategy formulation, and evaluation system development. The framework further advances computational modeling and provides crucial support for multi-scale analysis of TCR-pMHC recognition mechanisms and their biological functions.

The initiation of adaptive immune responses relies on the precise recognition and interpretation of antigenic information. In this process, the specific binding of T cell receptors (TCRs) to peptide-major histocompatibility complex (pMHC) molecules represents one of the key molecular events in the initiation of adaptive immune responses. Accordingly, the structural features of TCR-pMHC complexes provide a fundamental basis for dissecting antigen recognition mechanisms and support rational vaccine design, therapeutic target discovery in TCR-based immunotherapy, and TCR identification and optimization. However, experimental determination of TCR-pMHC structures remains costly, time-consuming, and limited in coverage, making computational approaches essential for rapidly obtaining reliable structural information. Computational methods for predicting the structures of TCR-pMHC complexes have advanced rapidly in recent years, driven by progress in deep learning-based modeling frameworks and the increasing availability of structural and sequence resources. Despite these developments, most existing tools do not adequately distinguish the key structural and biophysical differences between MHC class I (MHC-I) and MHC class II (MHC-II) complexes during model construction. As a consequence, their predictive performance differs substantially between class I and class II complexes. In general, structural predictions for class I complexes outperform those for class II complexes. This discrepancy may be related to several fundamental differences between the two systems, including the architecture of the peptide-binding groove, the distribution of peptide lengths, and the properties of peptide flanking residues (PFRs). Compared with MHC-I molecules, MHC-II molecules usually bind longer antigenic peptides, which typically range from 13 to 25 amino acids in length. PFRs at both termini of these peptides participate in regulating the overall conformation of TCR-pMHC class II complexes and exert a pronounced effect on the geometric and physicochemical characteristics of the TCR-pMHC binding interface. Furthermore, within the TCR recognition interface, the complementarity-determining regions (CDRs) consist of segments that differ markedly in conformational behavior. They commonly include regions that are relatively rigid and structurally stable, together with highly flexible segments exhibiting substantial conformational plasticity. These rigidity-flexibility features constitute an essential structural basis enabling TCRs to recognize diverse peptide-MHC ligands and to accommodate conformational heterogeneity at the interface. However, many current modeling tools, in an effort to enforce global conformational stability or reduce structural noise, tend to over-constrain intrinsically flexible regions. Such oversimplification may lead to inappropriate rigidification of flexible CDR loops, resulting in local structural distortions, compromised interface geometry, or even complete modeling failure for specific complexes. Against this background, the review approaches the field from the perspective of computational differences between MHC-I and MHC-II complexes. We first systematically organize and summarize available resources related to TCRs and pMHCs, including structural datasets, sequence databases, prediction tools, and benchmarking studies. We then focus on five representative tools capable of predicting both class I and class II complexes—AlphaFold2, AlphaFold3, TCRmodel2, tFold-TCR, and TCR-pHLA_ModellerS. After excluding structures present in the training sets of these tools, we constructed a benchmark dataset comprising 25 class I and 10 class II TCR-pMHC complexes in the bound state and conducted a systematic evaluation using this dataset. We first employ widely used general evaluation metrics, including All-Atom Root Mean Square Deviation (All-Atom RMSD), Backbone RMSD, Template Modeling score (TM-score), and DockQ, to assess the global conformational accuracy and interface modeling quality of class I and class II complexes. For class II complexes, we propose for the first time a peptide flanking residue deviation index, including the PFRs-Deviation Index (PFRs-DI), N-PFR-Deviation Index (N-PFR-DI), and C-PFR-Deviation Index (C-PFR-DI), to quantitatively characterize conformational deviations in PFRs. In addition, we propose the CDR conformational consistency index (CCC) designed to qualitatively evaluate the ability of prediction tools to capture TCR CDR conformational flexibility. These metrics collectively assess a tool’s ability to model both overall conformation and critical functional regions, thereby addressing the limitations of existing evaluation criteria that overemphasize global structure while inadequately capturing modeling quality in key functional areas. This establishes a unified analytical framework for MHC-I and MHC-II complexes to guide data resource selection, modeling strategy formulation, and evaluation system development. The framework further advances computational modeling and provides crucial support for multi-scale analysis of TCR-pMHC recognition mechanisms and their biological functions.

Ursodeoxycholic acid(UDCA)is a naturally occurring,low-toxicity,and hydrophilic bile acid(BA)in the human body that is converted by intestinal flora using primary BA.Solute carrier family 7 member 11(SLC7A11)functions to uptake extracellular cystine in exchange for glutamate,and is highly expressed in a variety of human cancers.Retroperitoneal liposarcoma(RLPS)refers to liposarcoma originating from the retroperitoneal area.Lipidomics analysis revealed that UDCA was one of the most significantly down-regulated metabolites in sera of RIPS patients compared with healthy subjects.The augmentation of UDCA concentration(≥25 μg/mL)demonstrated a suppressive effect on the proliferation of liposarcoma cells.[15N2]-cystine and[13Cs]-glutamine isotope tracing revealed that UDCA impairs cystine uptake and glutathione(GSH)synthesis.Mechanistically,UDCA binds to the cystine transporter SLC7A11 to inhibit cystine uptake and impair GSH de novo synthesis,leading to reactive oxygen species(ROS)accumulation and mitochondrial oxidative damage.Furthermore,UDCA can promote the anti-cancer effects of ferroptosis inducers(Erastin,RSL3),the murine double minute 2(MDM2)inhibitors(Nutlin 3a,RG7112),cyclin dependent kinase 4(CDK4)inhibitor(Abemaciclib),and glutaminase inhibitor(CB839).Together,UDCA functions as a cystine exchange factor that binds to SLC7A11 for antitumor activity,and SLC7A11 is not only a new transporter for BA but also a clinically applicable target for UDCA.More importantly,in combination with other antitumor chemotherapy or physiotherapy treatments,UDCA may provide effective and promising treatment strategies for RLPS or other types of tumors in a ROS-dependent manner.

Objective:To explore the clinical and pathological features and survival outcomes of patients with early-onset intrahepatic cholangiocarcinoma (EOICC).Methods:This is a multicenter, retrospective cohort study. Data of 1 160 intrahepatic cholangiocarcinoma patients undergoing radical resection in 14 tertiary Grade A hospitals in China from January 2010 to November 2021 were retrospectively collected. The cohort included 632 males and 528 females, aged( M (IQR)) 61 (14) years (range: 22 to 93 years). ICC aged ≤50 years at the time of diagnosis was defined as EOICC and >50 years as late-onset intrahepatic cholangiocarcinoma (LOICC). Of these, there were 247 cases in the EOICC group and 913 cases in the LOICC. The clinical and pathological characteristics of both groups were analyzed and compared using the independent sample t-test, Mann-Whitney U test or Kaplan-Meier method. Univariate and multivariate Cox regression models for patient outcomes were constructed and forest graphed. Results:Compared with the patients in the LOICC group, patients in the EOICC group had lower carcinoembryonic antigen levels (2.5(4.0) μg/L vs. 3.1(5.2)μg/L, U=124 899, P=0.009) and CA19-9 level (63.4(524.7)U/ml vs. 77.9(611.3)U/ml, U=120 320, P=0.013), higher levels of ALT (29(35)U/L vs. 24(26)U/L, U=101 214, P=0.013), a lower score of the Eastern US Cooperative Oncology Group (0 score patients: 54.7% vs. 44.1%, χ2=12.472, P=0.014), higher TNM stage ( χ2=11.807, P=0.038), and proportion of lymph node dissection (62.3% vs. 54.1%, χ2=5.355, P=0.021). Patients in the two groups in sex, first diagnosis symptoms, intrahepatic bile duct stone history, nail protein, albumin, total bilirubin, transaminase, liver function Child-Pugh grade, T stage, stage, N stage, preoperative laparoscopic exploration proportion, tumor diameter, vascular invasion proportion, differentiation, margin, intraoperative bleeding, postoperative complications, postoperative hospital days were no statistical significance (all P>0.05). Patients in the EOICC group had better outcomes than the LOICC group (median survival time: 29.7 months vs. 25.0 months, 3-year overall survival: 45.1% vs. 37.8%, P=0.027). Conclusion:EOICC patients are better than LOICC patients in carcinoembryonic antigen, CA19-9, ALT, physical strength status and TNM stage, and the long-term prognosis is also better than LOICC patients.

To establish a method for detecting Toxoplasma gondii based on recombinant polymerase amplification(RPA)technology and apply it to clinical sample validation of pet cats.Using the 529 repeat sequence of the Toxoplasma gondii gene as the target gene sequence,primers and probes were designed,and the Rep-529 recombinant plasmid was constructed as the standard.A fluorescent RPA reaction system was established.Dilute the plasmid standard 10 times to different concentrations as the detection template for sensitivity testing;Specific testing was conducted using genomic DNA from several parasitic spe-cies,including Toxoplasma gondii,Cryptosporidium,Neosporidium,Trichinella spiralis,Giardia flagellata,Babesia bo-vis and Theileria annulata as templates;Simultaneously,fluorescence RPA and RT-PCR were used to detect 52 positive and 40 negative cats clinical samples,and the coincidence rate of the detection results of the two methods were compared and ana-lyzed.The RPA reaction system was successfully established using PTRep recombinant plasmid as the standard,ToxD-F/ToxD-R as the primer,and RepD-P as the fluorescent probe.The reaction temperature was constant at 39 ℃,the reaction time was 30 minutes,and the detection sensitivity was 1 copy/μL.There is no significant cross reaction with parasites such as Cryptosporidium,Neosporidium,Trichinella spiralis,Giardia,Babesia bovis and Theileria annulata,and the specificity is good.A total of 92 clinical fecal samples from cats were tested,and the positive coincidence rate of fluorescence RPA detection method was higher than that of conventional RT-PCR method(98.08％vs.82.69％),and the difference of the positive rate was not statistically significant(X2=1.392,P＞0.05).The fluorescence RPA detection method for Toxoplasma gondii suc-cessfully established in this study has the characteristics of being fast,sensitive,specific,accurate,and reliable.It can be used as a rapid clinical detection kit for Toxoplasma gondii in cats and other animals,providing new technical support for the subsequent epidemiological monitoring and precise clinical diagnosis of toxoplasmosis in cats,other animals,and humans in the future.

Aim To explore the protective effect of the isochroman compound Asperisochroman B(AB)on oxygen-glucose deprivation/reoxygenation(OGD/R)injury of neurons based on the PI3K/AKT/Foxo1 path-way and to reveal the related mechanism.Methods Primary neurons were cultured and the OGD/R model was constructed.The primary neurons were divided in-to the blank control group,OGD/R group,and AB low,medium,and high concentration(3,10,30 μmol·L-1)groups.The effects of AB on primary neurons were determined by CCK-8 assay,lactate dehydrogen-ase(LDH)release assay,and Hoechst 33342 stai-ning.The expression levels of PI3K,AKT,and Foxo1-related proteins were detected by Western blot.After intervention with the PI3K inhibitor(LY294002)and re-modeling and intervention with high concentra-tion of AB(30 μmol·L-1),the expression of PI3K/Foxo1 pathway-related proteins was detected by West-ern blot.Results Compared with the OGD/R group,AB could significantly increase the cell survival rate of primary neurons and reduce the release of LDH.The results of Hoechst 33342 and immunofluorescence stai-ning showed that AB reduced apoptosis after OGD/R injury.Western blot results showed that compared with the OGD/R group,after AB intervention,the expres-sion levels of Bcl-2 and NeuN proteins in neurons sig-nificantly increased(P＜0.01),and the expression level of Bax protein significantly decreased(P＜0.01).At the same time,it upregulated the expres-sion levels of p-AKT and PI3K proteins,promoted Foxo1 phosphorylation,and downregulated the expres-sion of Foxo1.Compared with the high-dose AB group,LY294002 could inhibit the changes of the a-bove indicators and reverse the protective effect of AB on OGD/R-injured primary neurons.Conclusions AB can alleviate oxygen-glucose deprivation/reoxygen-ation-induced neuronal injury,and its mechanism may be related to the activation of the PI3K/AKT/Foxo1 signaling pathway.

The application of sensors to the monitoring of spinal morphology and motion was reviewed in terms of the research object and monitoring index.The present situation of the application of sensors was introduced,such as inertial sensor,stretchable strain sensor and electromagnetic sensor.The deficiencies of sensors applied to the monitoring of spinal morphology and motion were analyzed,and the future directions of the application were pointed out.[Chinese Medical Equipment Journal,2025,46(6):105-110]

Phosgene is a highly reactive chemical substance and a prevalent chemical warfare agent,and it is vitally important for rapid and accurate detection of phosgene to counteract terrorist threats and industrial accidents.In this work,a phosgene probe,designated as SX-Pho,which incorporated benzimidazole and hydroxyl groups as recognition motifs,was prepared through Suzuki coupling and Debus-Radziszewski methodologies to incorporate an electron-donating carbazole moiety.This probe exhibited a large Stokes shift(Approximately 130 nm).Upon exposure to triphosgene/triethylamine conditions(in situ phosgene generation),the fluorescence emission of probe at 470 nm underwent significant quenching,with a 20-fold reduction in intensity,while the fluorescence lifetime decreased from 3.30 ns to 3.06 ns.Concentration titration experiments demonstrated that SX-Pho achieved a lower detection limit of 57.8 nmol/L with high specificity and interference resistance.Preton nuclear magnetic resonance spectroscopy(1H NMR),high-resolution mass spectrometry,and density functional theory(DFT)calculations confirmed the cyclization reaction between hydroxyl groups,imines,and phosgene.The extent of overlap between the highest occupied molecular orbital(HOMO)and the lowest unoccupied molecular orbital(LUMO)was notably decreased,leading to the suppression of radiative transitions.The energy gap underwent a reduction of 0.43 eV,while the non-radiative transition was augmented,resulting in fluorescence quenching and achieving rapid detection of phosgene.Based on this,probe-loaded test strips were prepared.The color change under 365 nm illumination allowed visual discrimination of phosgene at concentrations below 20 μL/L.Furthermore,using a smartphone's built-in RGB application to measure the intensity of the blue(B)channel after the test strips were exposed to phosgene enabled both qualitative and quantitative detection.The detection range was 1.82-50 μL/L,with a limit of detection(LOD)of 1.814 μL/L.

AIM To investigate the ameliorative effects of Compound Fufangteng Mixture(CFM)on cyclophosphamide(CTX)-induced immunosuppression in mice.METHODS Forty-eight male C57BL/6J mice were randomly divided into the blank control group,the model group,the levamisole hydrochloride group(40 mg/kg)and the low-dose,medium-dose and high-dose CFM groups(3.75,7.5,10 g/kg),with 8 mice in each group,and given respective intervention orally once daily for 14 days.On the 5th to 7th day of administration,with the blank control group given normal saline intraperitoneally,the other groups underwent intraperitoneal CTX injections(80 mg/kg).24 hours after the last administration,organ indices of thymus and spleen were calculated;splenic histopathological alterations were assessed by HE staining;serum levels of IL-2,IL-6 and IgG were quantified using ELISA;splenic CD4+,CD8+T lymphocytes,alongside CD86+and CD206+macrophages populations were analyzed by flow cytometry;and splenic expression of CD4,CD8 and F4/80 was evaluated by immunohistochemical staining.RESULTS In CTX-treated mice,CFM administration mitigated body weight loss;enhanced thymus weight and thymic index;ameliorated splenic immune cell populations,elevated serum levels of cytokines IL-2,IL-6 and IgG in serum;and upregulated splenic levels of CD45+CD3+T lymphocytes and F4/80+CD11b+macrophages,alongside increasing the expression of CD4,CD8 and F4/80 surface markers.CONCLUSION CFM alleviates CTX-induced immunosuppression state in mice by modulating immune cells,restoring immune function and enhancing anti-inflammatory and tissue repair capabilities.

Objective To explore the time-varying characteristics and correlation degree of autonomous rehabili-tation behavior and related symptoms of middle-aged stroke patients,and to provide a basis for clinical transitional nursing and precise rehabilitation.Methods Ecological momentary assessment was used to select 57 middle-aged stroke patients who underwent rehabilitation treatment in the Rehabilitation Medicine Department of a tertiary com-prehensive hospital in Wuhan from March 15 to August 30,2024,using convenience sampling method.Their au-tonomous rehabilitation behavior and related symptoms(fatigue,pain,emotion,sensation)were continuously monitored for 2 weeks.A hierarchical linear model was used to analyze the correlation between behavior and symptoms.Results The autonomous rehabilitation behavior of middle-aged stroke patients showed a fluctuating increasing trend,and the symptom score showed a slow decreasing trend.The hierarchical linear model showed that compared with female patients,male patients have longer duration of autonomous rehabilitation behavior(P＜0.05).The number and duration of autonomous rehabilitation behaviors in patients without fatigue were higher(P＜0.05).The number of autonomous rehabilitation behaviors in patients without pain was higher than that in patients with pain(P＜0.05).The number of autonomous rehabilitation behavior items among patients who perceived more pleasure in rehabilitation was higher than that among patients with greater difficulty in rehabilitation challenges(P＜0.05).Patients with high rehabilitation confidence have higher numbers and duration of autonomous rehabilitation behaviors compared to pa-tients with low rehabilitation confidence(P＜0.05).Conclusion There are significant individual differences and dy-namic changes in the autonomous rehabilitation behavior and related symptoms of middle-aged stroke patients.Nurs-ing staff should accurately implement personalized rehabilitation services during the transition period,enhance pa-tients'autonomy and self-management ability in home-based rehabilitation,in order to improve the overall rehabilita-tion effect.