DRAMP 3.0: an enhanced comprehensive data repository of antimicrobial peptides.

Stapled antimicrobial peptides are an emerging class of artificial cyclic peptide molecules which have antimicrobial activity and potent structure stability. We previously published the Data Repository of Antimicrobial Peptides (DRAMP) as a manually annotated and open-access database of antimicrobial peptides (AMPs). In the update of version 3.0, special emphasis was placed on the new development of stapled AMPs, and a subclass of specific AMPs was added to store information on these special chemically modified AMPs. To help design low toxicity AMPs, we also added the cytotoxicity property of AMPs, as well as the expansion of newly discovered AMP data. At present, DRAMP has been expanded and contains 22259 entries (2360 newly added), consisting of 5891 general entries, 16110 patent entries, 77 clinical entries and 181 stapled AMPs. A total of 263 entries have predicted structures, and more than 300 general entries have links to experimentally determined structures in the Protein Data Bank. The update also covers new annotations, statistics, categories, functions and download links. DRAMP is available online at http://dramp.cpu-bioinfor.org/.

CD24 is a novel target of chimeric antigen receptor T cells for the treatment of triple negative breast cancer.

Triple negative breast cancer (TNBC) is a subtype of breast cancer with the highest degree of malignancy and the worst prognosis. The application of immunotherapy for TNBC is limited. This study was to verify the potential application of chimeric antigen receptor-T cells (CAR-T cells) targeting CD24 named as 24BBz in treatment of TNBC. 24BBz was constructed by lentivirus infection and then was co-culture with breast cancer cell lines to evaluate the activation, proliferation and cytotoxicity of engineered T cells. The anti-tumor activity of 24BBz was verified in the subcutaneous xenograft model of nude mice. We found that CD24 gene was significantly up-regulated in breast cancer (BRCA), especially in TNBC. 24BBz showed antigen-specific activation and dose-dependent cytotoxicity against CD24-positive BRCA tumor cells in vitro. Furthermore, 24BBz showed significant anti-tumor effect in CD24-positive TNBC xenografts and T cells infiltration in tumor tissues, while some T cells exhibited exhaustion. No pathological damage of major organs was found during the treatment. This study proved that CD24-specific CAR-T cells have potent anti-tumor activity and potential application value in treatment of TNBC.

Correlation between negative life events and suicide attempts among Yi adolescents with HIV/AIDS in Liangshan Prefecture.

OBJECTIVE: To investigate the incidence of suicide attempts among adolescents with HIV/AIDS in Liangshan Prefecture, Sichuan Province, as well as the correlation between negative life events, sleep, exercise, drug therapy and suicide attempts. METHODS: A total of 180 Yi adolescents aged 11-19 years with HIV/AIDS in a county of Liangshan Prefecture, Sichuan Province, China, were investigated by census. The main outcome indicators included the incidence of suicide attempts and whether negative life events, sleep, exercise, drug therapy and other factors were related to suicide attempts. RESULTS: We found that the incidence rate of suicide attempts among Yi adolescents with HIV/AIDS in Liangshan Prefecture was 13.9%. Negative life events were a risk factor for suicide attempts (OR = 1.047, p < 0.001, 95% CI 1.027-1.067). In the factors of negative life events, adaptation was a risk factor for suicide attempts (OR = 1.203, p = 0.026, 95% CI 1.022-1.416), and academic pressure showed a tendency to be a risk factor for suicide attempts (OR = 1.149, p = 0.077, 95% CI 0.985-1.339). However, the punishment factor, interpersonal stress factor and loss factor had no significant correlation with suicide attempts. There was no significant correlation between sleep, exercise, drug therapy and suicide attempts. CONCLUSION: The proportion of suicide attempts among Yi adolescents with HIV/AIDS in Liangshan Prefecture is high and should be considered. Negative life events are independent risk factors for suicide attempts, and it is necessary to strengthen the screening and early intervention for suicide attempts in HIV/AIDS adolescents with definite negative life events.

Micropeptide MIAC inhibits the tumor progression by interacting with AQP2 and inhibiting EREG/EGFR signaling in renal cell carcinoma.

BACKGROUND: Although, micropeptides encoded by non-coding RNA have been shown to have an important role in a variety of tumors processes, there have been no reports on micropeptide in renal cell carcinoma (RCC). Based on the micropeptide MIAC (micropeptide inhibiting actin cytoskeleton) discovered and named in the previous work, this study screened its tumor spectrum, and explored its mechanism of action and potential diagnosis and treatment value in the occurrence and development of renal carcinoma. METHODS: The clinical significance of MIAC in RCC was explored by bioinformatics analysis through high-throughput RNA-seq data from 530 patients with kidney renal clear cell carcinoma (KIRC) in the TCGA database, and the detection of clinical samples of 70 cases of kidney cancer. In vitro and in vivo experiments to determine the role of MIAC in renal carcinoma cell growth and metastasis; High-throughput transcriptomics, western blotting, immunoprecipitation, molecular docking, affinity experiments, and Streptavidin pulldown experiments identify MIAC direct binding protein and key regulatory pathways. RESULTS: The analysis of 600 renal carcinoma samples from different sources revealed that the expression level of MIAC is significantly decreased, and corelated with the prognosis and clinical stage of tumors in patients with renal carcinoma. Overexpression of MIAC in renal carcinoma cells can significantly inhibit the proliferation and migration ability, promote apoptosis of renal carcinoma cells, and affect the distribution of cells at various stages. After knocking down MIAC, the trend is reversed. In vivo experiments have found that MIAC overexpression inhibit the growth and metastasis of RCC, while the synthetized MIAC peptides can significantly inhibit the occurrence and development of RCC in vitro and in vivo. Further mechanistic studies have demonstrated that MIAC directly bind to AQP2 protein, inhibit EREG/EGFR expression and activate downstream pathways PI3K/AKT and MAPK to achieve anti-tumor effects. CONCLUSIONS: This study revealed for the first time the tumor suppressor potential of the lncRNA-encoded micropeptide MIAC in RCC, which inhibits the activation of the EREG/EGFR signaling pathway by direct binding to AQP2 protein, thereby inhibiting renal carcinoma progression and metastasis. This result emphasizes that the micropeptide MIAC can provide a new strategy for the diagnosis and treatment of RCC.

RPS6KA5 methylation predict response to 6-week treatment for adolescent MDD patients.

OBJECTIVE: We aimed to investigate the effect of differentially methylated genes and chronic childhood stress on the development of depressive symptoms in Chinese adolescents, as well as to test whether methylation at baseline can be used as a predictor of remission at follow-up after six weeks of treatment. METHODS: After recruiting 87 MDD patients and 53 healthy controls, we compared demographic and baseline clinical characteristics. The Childhood Chronic Stress Questionnaire was used to assess stress caused by early-life events. MDD patients underwent six weeks of treatment, and response to treatment was assessed using the Beck Depression Inventory-II. In addition, four MDD patients and five controls were randomly chosen for genome-wide methylation analysis. RESULTS: The gene RPS6KA5 showed significant methylation differences between the two groups. Severity of chronic childhood stress was significantly associated with increased risk of depression in adolescents, but not with treatment response. Baseline RPS6KA5 methylation can predict remission after six weeks of treatment. We did not observe any interaction between RPS6KA5 methylation and chronic childhood stress. CONCLUSIONS: Our results suggest that RPS6KA5 methylation can be used as a predictor of response to treatment in adolescent MDD patients. Here we offer new evidence for the role of epigenetics in early response to treatment of depression. TRIAL REGISTRATION: ChiCTR, ChiCTR2000033402, 31/05/2020, http://www.chictr.org.cn/index.aspx.

Research progress on high throughput discovery and functional verification of functional micropeptides.

With the rapid development of computational biology and deep sequencing technology, more and more studies have shown that a large number of non-classical open reading frames that have not been annotated and hidden in non-coding RNA can encode functional micropeptide. This article reviewed the current research status and technology strategy of gene sources, biological properties, predicted methods and functional verification of micropeptide, providing theoretical and reference basis for the subsequent discovery of micropeptides, research on regulatory mechanisms and development of novel targets and biomarkers.

Increased occurrence of PTSD symptoms in adolescents with major depressive disorder soon after the start of the COVID-19 outbreak in China: a cross-sectional survey.

BACKGROUND: The Coronavirus Disease 2019 (COVID-19) pandemic continues to threaten the physical and mental health of people across the world. This study aimed to understand the psychological impact of this disease on adolescents with major depressive disorder (MDD) at 1 month after the start of the outbreak in China. METHODS: Using the Children's Impact of Event Scale (CRIES-13) questionnaire, we investigated the occurrence of posttraumatic stress disorder (PTSD) in two groups of adolescents: MDD patients who were in continuous antidepressant therapy and healthy controls. Total scores and factor subscores were compared between the two groups and subgroups stratified by sex and school grade. Logistic regression was used to identify variables associated with high total CRIES-13 scores. RESULTS: Compared to controls (n = 107), the MDD group (n = 90) had higher total CRIES-13 scores and a higher proportion with a total score ≥ 30. They also had a lower intrusion subscore and a higher arousal subscore. In the MDD group, males and females did not differ significantly in total CRIES-13 scores or factor subscores, but junior high school students had higher avoidance subscores than senior high school students. Logistic regression showed high total CRIES-13 scores to be associated with MDD and the experience of "flashbacks" or avoidance of traumatic memories associated with COVID-19. CONCLUSIONS: It is crucial to understand the psychological impact of COVID-19 on adolescents with MDD in China, especially females and junior high school students. Long-term monitoring of adolescents with a history of mental illness is required to further understand these impacts. TRIAL REGISTRATION: ChiCTR, ChiCTR2000033402 , Registered 31 May 2020.

Increased symptoms of post-traumatic stress in school students soon after the start of the COVID-19 outbreak in China.

BACKGROUND: The outbreak of Coronavirus Disease 2019(COVID-19) caused psychological stress in Chinese adults population. But we are unaware of whether the pandemic causes psychological stress on children. METHODS: We used the Children's Impact of Event Scale questionnaire (CRIES-13) to investigate the degree of Post-traumatic Stress (PTSD) symptoms caused by the pandemic in students selected from schools in Sichuan, Jiangsu, Henan, Yunnan, and Chongqing provinces of China. RESULTS: A total of 7769 students(3692 male and 4077 female), aged 8-18 years, were enrolled in the study, comprising 1214 in primary schools, 2799 in junior high schools and 3756 in senior high schools. A total of 1639 students (21.1%) had severe psychological stress reactions. A large proportion of senior high school students (23.3%) experienced severe psychological stress, and they had the highest median total CRIES-13 score. Female students were more likely to experience severe psychological stress and had higher median CRIES-13 total scores than males. CONCLUSION: COVID-19 has placed psychological stresses on primary and secondary school students in China. These stresses are more likely to reach severe levels among female students and senior high school students.

Characterization of the complete mitochondrial genome of Drawida gisti (Metagynophora, Moniligastridae) and comparison with other Metagynophora species.

Here, the complete mitochondrial genome (mitogenome) of Drawida gisti was sequenced and compared with the mitogenomes of other Metagynophora species. The circular mitogenome was 14,648 bp in length and contained two ribosomal RNA genes (rRNAs), 13 protein-coding genes (PCGs), and 22 transfer RNA genes (tRNAs). The types of constitutive genes and the direction of the coding strand that appeared in Drawida mitogenome were identical to those observed in other Metagynophora species, except for a missing lengthy non-coding region. The conservative relationships between Drawida species were supported by the overall analyses of 13 PCGs, two rRNAs, and 22 tRNAs. A comparison of the Metagynophora mitogenomes revealed that the ATP8 gene possessed the highest polymorphism among the 13 PCGs and two rRNAs. Phylogenetic analysis suggested that the Moniligastridae contained Drawida, which is a primitive Metagynophora group. Our study provides a step forward toward elucidating the evolutionary linkages within Drawida and even Metagynophora.

[Progress on sORF-encoded micropeptides].

Existing research has shown that there are a large amount of non-coding RNAs (ncRNAs) in organisms. Short open reading frames (sORFs) abundantly exist in molecular sequences inaccurately annotated as ncRNAs. Several sORFs can be transcribed and translated into evolutionarily conserved micropeptides, which were ignored in previous studies due to short sequence lengths and the limitations of research techniques. To date, sORF-encoded micropeptides with various functions have been found to play important roles in regulating vital biological activities. This article reviews the functional micropeptides which have been found in recent years, introduces the new micropeptide designated as MIAC that we have discovered and describes the related technologies for mining potential micropeptides, thereby providing insights and references for new micropeptide discovery for researchers.

Micropeptide MIAC Inhibits HNSCC Progression by Interacting with Aquaporin 2.

Several important micropeptides encoded by noncoding RNAs have been identified in recent years; however, there have never been any reports of micropeptides in head and neck squamous cell carcinoma (HNSCC). Here we report the discovery and characterization of a human endogenous peptide named micropeptide inhibiting actin cytoskeleton (MIAC). Comprehensive analysis of the TCGA (The Cancer Genome Atlas) database (n = 500), clinical fresh samples (n = 94), and tissue microarrays (n = 60) revealed that lower MIAC expression is correlated with poor overall survival of HNSCC patients. Meanwhile, RNA-sequencing analysis of 9657 human tissues across 32 cancer types from TCGA cohorts found that MIAC is significantly associated with the progression of 5 other different tumors. Mechanistically, MIAC directly interacts with AQP2 (Aquaporin 2) to inhibit the actin cytoskeleton by regulating SEPT2 (Septin 2)/ITGB4 (Integrin Beta 4) and ultimately suppressing the tumor growth and metastasis of HNSCC. Collectively, the mechanism investigation and evaluation of MIAC activity in vivo and in vitro highlights that MIAC plays an important role in HNSCC tumorigenesis.

Enhanced Safety and Antitumor Efficacy of Switchable Dual Chimeric Antigen Receptor-Engineered T Cells against Solid Tumors through a Synthetic Bifunctional PD-L1-Blocking Peptide.

Chimeric antigen receptor (CAR)-engineered T cells (CAR-Ts) therapy has an excellent efficacy in cancer treatment, especially its impressive results in hematological malignancies. Unfortunately, its application on solid tumors is challenged by the off-target effects caused by lacking of tumor specific antigens and the immunosuppression caused by the tumor microenvironment. We constructed a switchable dual receptor CAR-T cell (sdCAR-T) whose activity relied upon double antigens (mesothelin and fluorescein isothiocyanate) and was strictly controlled by a "switch" (FPBM) consisting of a PD-L1 blocking peptide conjugated to fluorescein isothiocyanate. SdCAR-T cells were activated only when FPBM and cognate tumor cells expressing both PD-L1 and mesothelin coexist. Importantly, long-term proliferation experiments in vitro and the pharmacodynamic study in vivo showed a stronger antitumor activity of this system compared to the second generation mesothelin CAR-T cells. In view of this novel treatment paradigm being safer and more effective than traditional CAR-T cells, it may become a new strategy for the treatment of solid tumors.

NK cell-derived exosomes carry miR-207 and alleviate depression-like symptoms in mice.

BACKGROUND: Depression is a common mental disease that mainly manifests as bad mood, decreased interest, pessimism, slow thinking, lack of initiative, poor diet and sleep. Patients with severe depression have suicidal tendencies. Exosomes are small vesicles released by the fusion of a multivesicular body and membranes, and they contain specific proteins, nucleic acids, and lipids related to the cells from which they originate. MicroRNAs (miRNAs) are 20-24 nt RNAs that can be packaged into exosomes and can play important regulatory roles. Astrocytes are the most abundant cell population in the central nervous system and have a close link to depression. Astrocyte activation could result in the release of inflammatory cytokines, including IL-1ß, IL-6, and TNF-α, which could promote the symptoms of depression. In previous research, our team confirmed that NK cells regulate depression in mice. Here, we propose that miRNA in the exosomes from NK cells performs this antidepressant function. METHODS: Exosomes from NK cells were shown by in vivo and in vitro experiments to alleviate symptoms of chronic mild stress in mice and decrease pro-inflammatory cytokines release from astrocytes. The production of pro-inflammatory cytokines was assessed by ELISA. Microarray analysis was used to identify critical miRNAs. Luciferase reporter assays, qPCR, and other experiments were used to prove that exosomal miR-207 has an important role in alleviating the symptoms of stress in mice. RESULTS: MiRNA-containing exosomes from NK cells could alleviate symptoms of chronic mild stress in mice. In vivo experiments showed that these exosomes decreased the levels of pro-inflammatory cytokines (IL-1ß, IL-6, and TNF-α) released by astrocytes. By microarray analysis of exosome miRNA profiles, miR-207 was found to be overexpressed in exosomes derived from unstressed mice. Experiments confirmed that miR-207 directly targets TLR4 interactor with leucine-rich repeats (Tril) and inhibits NF-κB signaling in astrocytes. MiR-207 could decrease the release of pro-inflammatory cytokines and inhibit expression of Tril in vitro. In vivo experiments revealed that exosomes with low miR-207 levels showed decreased antidepressant activity. CONCLUSION: Collectively, our findings revealed that exosomal miR-207 alleviated symptoms of depression in stressed mice by targeting Tril to inhibit NF-κB signaling in astrocytes.

Antiangiogenic activity of terpenoids from Euphorbia neriifolia Linn.

Angiogenesis is known to serve an important role in embryonic development, wound healing, tissue regeneration, and growth. Two new abietane-type diterpenoids (3, 5), a new lanosterol triterpenoid (8) and seven known compounds haven been isolated from the Euphorbia neriifolia Linn. The structures of all compounds were elucidated by spectroscopic analysis and comparing their NMR data with reported data. Furthermore, we found that compounds 6 and 9 had the antiangiogenic effects in vitro. They could inhibit HUVEC migration and microvessel sprouting in rat aortic rings. Moreover, compound 6 inhibited VEGFR and phosphorylation of Akt, but compound 9 only shown inhibitory effect on phosphorylation of Akt. Taken together, these results suggest that inhibition of VEGF signaling and downstream pathways may be responsible for the antiangiogenic activity of compounds 6 and 9.

Novel Peptide CM 7 Targeted c-Met with Antitumor Activity.

Anomalous changes of the cell mesenchymal-epithelial transition factor (c-Met) receptor tyrosine kinase signaling pathway play an important role in the occurrence and development of human cancers, including gastric cancer. In this study, we designed and synthesized a novel peptide (CM 7) targeting the tyrosine kinase receptor c-Met, that can inhibit c-Met-mediated signaling in MKN-45 and U87 cells. Its affinity to human c-Met protein or c-Met-positive cells was determined, which showed specific binding to c-Met with high affinity. Its biological activities against MKN-45 c-Met-positive cells were evaluated in vitro and in vivo. As a result, peptide CM 7 exhibited moderate regulation of c-Met-mediated cell proliferation, migration, invasion, and scattering. The inhibitory effect of peptide CM 7 on tumor growth in vivo was investigated by establishing a xenograft mouse model using MKN-45 cells, and the growth inhibition rate of tumor masses for peptide CM 7 was 62%. Based on our data, CM 7 could be a promising therapeutic peptide for c-Met-dependent cancer patients.

Potential therapeutic applications of exosomes in different autoimmune diseases.

Autoimmune diseases are caused by self-immune responses to autoantigens, which damage body tissues and severely affect the patient's quality of life. Therapeutic drugs are associated with adverse side effects and their beneficial effects are limited to specific populations. Evidence indicates that exosomes which are small vesicles secreted by most cell types and body fluids, and may play roles in both immune stimulation and tolerance since they are involved in many processes such as immune signaling, inflammation and angiogenesis. Exosomes have also emerged as promising tools for therapeutic delivery, given their intrinsic features such as stability, biocompatibility and a capacity for stealth. In this review, we summarize existing literature regarding the production, efficacy, action mechanism, and potential therapeutic uses of exosomes in the contexts of autoimmune diseases such as type 1 diabetes mellitus, multiple sclerosis, systemic lupus erythematosus, rheumatoid arthritis, and Sjogren's syndrome.

Mining for missed sORF-encoded peptides.

INTRODUCTION: Small open reading frames (sORFs) with potential protein-coding capacity have been disclosed in various transcripts, including long noncoding RNAs (LncRNAs), mRNAs (5'-upstream, coding domain, and 3'-downstream), circular RNAs, pri-miRNAs, and ribosomal RNAs (rRNAs). Recent characterization of several sORF-encoded peptides (SEPs or micropeptides) revealed their important roles in many fundamental biological processes in a broad range of species from yeast to human. The success in the mining of micropeptides attributes to the advanced bioinformatics and high-throughput sequencing techniques. Areas covered: sORFs and SEPs were overlooked for their tiny size and the difficulty of identification by bioinformatics analyses. With more and more sORFs and SEPs have been identified, this field has attracted more attention. This review covers recent advances in the strategies for the detection and identification of sORFs and SEPs. Expert commentary: The advantages and drawbacks of the strategies for detection and identification of sORFs and SEPs are discussed, as well as the techniques that are used to decipher the roles of micropeptides in organisms are described.

Peptide PD29 treats bleomycin-induced pulmonary fibrosis by inhibiting the TGF-ß/smad signaling pathway.

Pulmonary fibrosis (PF) is an end-stage change in lung disease characterized by fibroblast proliferation, massive extracellular matrix (ECM) aggregation with inflammatory damage, and severe structural deterioration. PD29 is a 29-amino acid peptide which has the potential to alleviate PF pathogenesis via three mechanisms: anti-angiogenesis, inhibition of matrix metalloproteinase activities, and inhibition of integrins. In this study, fibrotic lung injuries were induced in SD rats by a single intratracheal instillation of 5 mg/kg bleomycin (BLM). Then, these rats were administered 7.5, 5, or 2.5 mg/kg PD29 daily for 30 days. BLM induced-syndromes including structure distortion, excessive deposition of ECM, excessive inflammatory infiltration, and pro-inflammatory cytokine release were used to evaluate the protective effect of PD-29. Oxidative stress damage in lung tissues was attenuated by PD29 in a dose-dependent manner. The expression of TGF-ß1 and the phosphorylation of Smad-2/-3-its downstream targets-were enhanced by BLM and weakened by PD29. In vitro, PD29 inhibited TGF-ß1-induced epithelial-mesenchymal transition (EMT) and transformation in A549 cells and mouse primary fibroblasts into myofibroblasts. In summary, PD29 reversed EMT and transformation of fibroblasts into myofibroblasts in vitro and prevented PF in vivo possibly by suppressing the TGF-ß1/Smad pathway.

Anti-Tumor Activity and Pharmacokinetics of AP25-Fc Fusion Protein.

AP25 is an anti-tumor peptide with a high affinity for integrins. It exerts its anti-tumor activity by inhibiting angiogenesis and by directly inhibiting the growth of tumor cells. Its half-life time in vivo is only about 50 minutes, which limits its clinical application. In order to prolong the half-life time of AP25 while preserving its anti-tumor activity, several fusion proteins of AP25 and IgG4 Fc were designed and expressed; their anti-tumor activity and pharmacokinetics properties were evaluated. Firstly, four AP25-Fc fusion protein sequences were designed, and the corresponding proteins were expressed and purified. Based on the results of HUVEC migration inhibition assay, HUVEC and tumor cell proliferation inhibition assay and yields of expression by HEK293 cells, the fusion protein designated PSG4R was selected for further evaluation. The anti-tumor effect of PSG4R was then evaluated in vivo on HCT-116 nude mice xenograft model. And the pharmacokinetics properties of PSG4R were investigated in rats. The results showed that PSG4R could inhibit the growth of xenografts of human colon cancer cell line HCT-116 in nude mice by intravenous administration of 40 mg/kg once every two days. The half-life time of PSG4R was 56.270 ± 15.398 h. This study showed that the construction of AP25-Fc fusion protein could significantly prolong the half-life of AP25 while retaining its anti-tumor activity, which provides a new direction for new drug development of AP25.

Design and Synthesis of A PD-1 Binding Peptide and Evaluation of Its Anti-Tumor Activity.

Immune-checkpoint blockades, suchas PD-1 monoclonal antibodies, have shown new promising avenues to treat cancers. Failure responsesof many cancer patients to these agents have led to a massive need for alternative strategies to optimize tumor immunotherapy. Currently, new therapeutic developments involve peptide blocking strategies, as they have high stability and low immunogenicity. Here, we have designed and synthesized a new peptide FITC-YT-16 to target PD-1. We have studied FITC-YT-16 by various experiments, including Molecular Operating Environment MOE modeling, purification testing by HPLC and LC mass, peptide/PD-1 conjugation and affinity by microscale thermophoresis (MST), and T cell immune-fluorescence imaging by fluorescence microscopy and flow cytometry. The peptide was tested for its ability to enhanceT cell activity against tumor cell lines, including TE-13, A549, and MDA-MB-231. Lastly, we assessed T cell cytotoxicity under peptide treatment. YT-16⁻PD-1 interaction showed a high binding affinity as a low energy complex that was confirmed by MOE. Furthermore, the peptide purity and molecular weights were 90.96% and 2344.66, respectively. MST revealed that FITC-YT-16 interacted with PD-1 at a Kd value of 17.8 ± 2.6 nM. T cell imaging and flow cytometry revealed high affinity of FITC-YT-16 to PD-1. Interestingly, FITC-YT-16 efficiently blocked PD-1 signaling pathways and promoted T cell inflammatory responses by elevating IL-2 and INF-γ levels. Moreover, FITC-YT-16 has the ability to activate T cell cytotoxicity. Therefore, FITC-YT-16 significantly enhanced T cell anti-tumor activity by blocking PD-1⁻PD-L1 interactions.