DNA damage response-related immune activation signature predicts the response to immune checkpoint inhibitors: from gastrointestinal cancer analysis to pan-cancer validation

Objective: DNA damage response(DDR) deficiency has emerged as a prominent determinant of tumor immunogenicity. This study aimed to construct a DDR-related immune activation(DRIA) signature and evaluate the predictive accuracy of the DRIA signature for response to immune checkpoint inhibitor(ICI) therapy in gastrointestinal(GI) cancer.Methods: A DRIA signature was established based on two previously reported DNA damage immune response assays. Clinical and gene expression data from two published GI cancer cohorts were used to assess and validate the association between the DRIA score and response to ICI therapy. The predictive accuracy of the DRIA score was validated based on one ICI-treated melanoma and three pan-cancer published cohorts.Results: The DRIA signature includes three genes(CXCL10, IDO1, and IFI44L). In the discovery cancer cohort, DRIA-high patients with gastric cancer achieved a higher response rate to ICI therapy than DRIA-low patients(81.8% vs. 8.8%;P < 0.001), and the predictive accuracy of the DRIA score [area under the receiver operating characteristic curve(AUC) = 0.845] was superior to the predictive accuracy of PD-L1 expression, tumor mutational burden, microsatellite instability, and Epstein–Barr virus status. The validation cohort demonstrated that the DRIA score identified responders with microsatellite-stable colorectal and pancreatic adenocarcinoma who received dual PD-1 and CTLA-4 blockade with radiation therapy. Furthermore, the predictive performance of the DRIA score was shown to be robust through an extended validation in melanoma, urothelial cancer, and pan-cancer.Conclusions: The DRIA signature has superior and robust predictive accuracy for the efficacy of ICI therapy in GI cancer and pancancer, indicating that the DRIA signature may serve as a powerful biomarker for guiding ICI therapy decisions.

Emerging roles of plasmacytoid dendritic cell crosstalk in tumor immunity

Plasmacytoid dendritic cells(pDCs)are a pioneer cell type that produces type I interferon(IFN-I)and promotes antiviral immune responses.However,they are tolerogenic and,when recruited to the tumor microenvironment(TME),play complex roles that have long been a research focus.The interactions between p DCs and other components of the TME,whether direct or indirect,can either promote or hinder tumor development;consequently,p DCs are an intriguing target for therapeutic intervention.This review provides a comprehensive overview of p DC crosstalk in the TME,including crosstalk with various cell types,biochemical factors,and microorganisms.An in-depth understanding of p DC crosstalk in TME should facilitate the development of novel p DC-based therapeutic methods.

Prenatal programing of motivated behaviors:can innate immunity prime behavior?

Prenatal programming during pregnancy sets physiological outcomes in the offspring by integrating external or internal stimuli.Accordingly,pregnancy is an important stage of physiological adaptations to the environment where the fetus becomes exposed and adapted to the maternal milieu.Maternal exposure to high-energy dense diets can affect motivated behavior in the offs p ring leading to addiction and impaired sociability.A high-energy dense exposure also increases the pro-inflammatory cytokines profile in plasma and brain and favors microglia activation in the offspring.While still under investigation,prenatal exposure to high-energy dense diets promotes structural abnormalities in selective brain regions regulating motivation and social behavior in the offspring.The current review addresses the role of energy-dense foods programming central and peripheral inflammatory profiles during embryonic development and its effect on motivated behavior in the offspring.We provide preclinical and clinical evidence that supports the contribution of prenatal programming in shaping immune profiles that favor structural and brain circuit disruption leading to aberrant motivated behaviors after birth.We hope this minireview encourages future research on novel insights into the mechanisms underlying maternal programming of motivated behavior by central immune networks.

Downregulation of CD4+CD25+ regulatory T cells may underlie enhanced Th1 immunity caused by immunization with activated autologous T cells

Regulatory T cells （Treg） play important roles in immune system homeostasis, and may also be involved in tumor immunotolerance by suppressing Th1 immune response which is involved in anti-tumor immunity. We have previously reported that immunization with attenuated activated autologous T cells leads to enhanced anti-tumor immunity and upregulated Thl responses in vivo. However, the underlying molecular mechanisms are not well understood. Here we show that Treg function was significantly downregulated in mice that received immunization of attenuated activated autologous T cells. We found that Foxp3 expression decreased in CD4＋CD25＋ T cells from the immunized mice. Moreover, CD4＋CD25＋Foxp3＋ Treg obtained from immunized mice exhibited diminished immunosuppression ability compared to those from naive mice. Further analysis showed that the serum of immunized mice contains a high level ofanti-CD25 antibody （about 30 ng/ml, p〈0.01 vs controls）. Consistent with a role ofanti-CD25 response in the downregulation of Treg, adoptive transfer of serum from immunized mice to naive mice led to a significant decrease in Treg population and function in recipient mice. The triggering of anti-CD25 response in immunized mice can be explained by the fact that CD25 was induced to a high level in the ConA activated autologous T cells used for immunization. Our results demonstrate for the first time that immunization with attenuated activated autologous T cells evokes anti-CD25 antibody production, which leads to impeded CD4＋CD25＋Foxp3＋ Treg expansion and function in vivo. We suggest that dampened Treg function likely contributes to enhanced Thl response in immunized mice and is at least part of the mechanism underlying the boosted anti-tumor immunity.

Driving Forces of AIDS Pathogenesis:Massive CD4^+ T Lymphocyte Depletion and Abnormal Immune Activation

The occurrence of massive CD4+ T cell depletion is one of the most prominent characteristics of human immunodeficiency virus type 1 (HIV-1) infection during acute phase, resulting in unrestorable destruction to the immune system. The infected host undergoes an asymptomatic period lasting several years with low viral load and ostensibly healthy status, which is presumably due to virus-specific adaptive immune responses. In the absence of therapy, an overwhelming majority of cases develop to AIDS within 8-10 years of latent infection. In this review, we discuss the roles in AIDS pathogenesis played by massive CD4+ T lymphocytes depletion in gut-associated lymphoid tissue (GALT) during acute infection and abnormal immune activation emerging in the later part of chronic phase.

The immunity-promoting activity of porcine placenta in mice as an immunomodulator for functional foods

This study was to explore the immunity-promoting activity of porcine placenta as a potential raw material for functional foods.Porcine placenta was subjected to the analysis for its bioactive substances,and their immunity-promoting activity was determined in mice supplemented with porcine placenta extract(PPE)and freeze-dried porcine placenta powder at high(PPH)and low(PPL)dosage.Results showed that porcine placenta contained placental peptides and 15 free amino acids,and the amounts of estrogen and progesterone in products developed from porcine placenta were within the limit of national standard.Mice model experiment revealed that compared with the control,the PPH treatment significantly improved the spleen index(P<0.05)by increasing the phagocytic rate of macrophages from 20%to 60%and the conversion rate of T lymphocytes from 8%to 60%.The q PCR analysis disclosed that the porcine placenta powder enhanced mice immunity via promoting the expression of Th1 cytokines of interleukin-2(IL-2)and IFN-γ,especially the former,by almost 8 times in the spleens of male mice,while inhibited Th2 cytokines of IL-4 and IL-10.This investigation has provided a reference for the development of porcine placenta as a raw material applied in functional foods to improve human immunity.

Exposure to Hyaluronan and Radon-Containing Water during the Treatment of Periodontal Pockets

Hyaluronic acid (HA) preparations have emerged as pivotal components in contemporary dentistry, gaining widespread recognition for their multifaceted roles in various biological functions. Extensive literature underscores the significance of HA in maintaining tissue water balance, fostering cell proliferation, promoting rapid cell migration, influencing cell differentiation during organism development, and facilitating tissue regeneration. Notably, HA’s interactions with cell surface receptors contribute to the viscosity of synovial fluid, activate the immune system, and enhance cartilage elasticity. Beyond these established functions, HA has also been investigated for its potential involvement in determining and studying the hormetic effects of radon water, adding a novel dimension to its applications in dental research. A thorough exploration of existing studies reveals a nuanced understanding of how HA interventions impact the outcomes of dental procedures. The comprehensive scope of these investigations allows for a more accurate assessment of the potential effectiveness of specific interventions and provides valuable insights into post-procedural prognoses for individual patients. This synthesis of literature serves as the foundation for elucidating the intricate interplay between HA, radon exposure, and their relevance in modern dental practices.

Studies on Active Polysaccharides from Ganoderma lucidum vith Immune Activity

从云头状灵芝[Ganoderma Lucidum(Leyss.ex Fr.)Karst.]中分离得到三种灵芝多糖BN3A，BN3B及BN3C，它们均表现明显免疫调节作用。从灵芝多糖BN3B及BN3C中各分离得到四个多糖均一体，对其中主要成分BN3C1，BN3C3，BN3B1及BN3B3进行了物理及化学研究，它们的平均分子量依次为1.6×10^4，2.5×10^4，3.5×10^4及4.0×10^4。经完全酸水解、红外光谱测定、过碘酸氧化、甲酸生成、Smith降解等证明，BN3B1及BN3C1均为β－（1→6)(1→3）甙键相连的葡聚糖。BN3B3为阿拉伯半乳聚糖。BN3C3为由葡萄糖和阿拉伯糖组成的肽多糖。它们均为β－（1→6）（1→3）甙键相连。

Impact of psychological stress on irritable bowel syndrome

Psychological stress is an important factor for the development of irritable bowel syndrome(IBS). More and more clinical and experimental evidence showed that IBS is a combination of irritable bowel and irritable brain. In the present review we discuss the potential role of psychological stress in the pathogenesis of IBS and provide comprehensive approaches in clinical treatment. Evidence from clinical and experimental studies showed that psychological stresses have marked impact on intestinal sensitivity, motility, secretion and permeability, and the underlying mechanism has a close correlation with mucosal immune activation, alterations in central nervous system, peripheral neurons and gastrointestinal microbiota. Stress-induced alterations in neuro-endocrine-immune pathways acts on the gut-brain axis and microbiota-gut-brain axis, and cause symptom flare-ups or exaggeration in IBS. IBS is a stresssensitive disorder, therefore, the treatment of IBS should focus on managing stress and stress-induced responses. Now, non-pharmacological approaches and pharmacological strategies that target on stress-related alterations, such as antidepressants, antipsychotics, miscellaneous agents, 5-HT synthesis inhibitors, selective 5-HT reuptake inhibitors, and specific 5-HT receptor antagonists or agonists have shown a critical role in IBS management. A integrative approach for IBS management is a necessary.

Gender-related differences in irritable bowel syndrome: Potential mechanisms of sex hormones

According to epidemiological studies,twice as many women as men are affected by irritable bowel syndrome(IBS)in western countries,suggesting a role for sex hormones in IBS pathophysiology.Despite growing evidence about the implications of sex hormones in IBS symptom modulation,data on mechanisms by which they influence disease development are sparse.This review aims to determine the state of knowledge about the role of sex hormones in sensorimotor dysfunctions and to address the possible interplay of sex hormones with common risk factors associated with IBS.The scientific bibliography was searched using the following keywords:irritable bowel syndrome,sex,gender,ovarian hormone,estradiol,progesterone,testosterone,symptoms,pain,sensitivity,motility,permeability,stress,immune system,brain activity,spinal,supraspinal,imaging.Ovarian hormones variations along themenstrual cycle affect sensorimotor gastrointestinal function in both healthy and IBS populations.They can modulate pain processing by interacting with neuromodulator systems and the emotional system responsible for visceral pain perception.These hormones can also modulate the susceptibility to stress,which is a pivotal factor in IBS occurrence and symptom severity.For instance,estrogen-dependent hyper-responsiveness to stress can promote immune activation or impairments of gut barrier function.In conclusion,whereas it is important to keep in mind that ovarian hormones cannot be considered as a causal factor of IBS,they arguably modulate IBS onset and symptomatology.However,our understanding of the underlying mechanisms remains limited and studies assessing the link between IBS symptoms and ovarian hormone levels are needed to improve our knowledge of the disease evolution with regard to gender.Further studies assessing the role of male hormones are also needed to understand fully the role of sex hormones in IBS.Finally,investigation of brain-gut interactions is critical to decipher how stress,ovarian hormones,and female brain processing of pain can translate into gut dysfunctions.

Pathophysiology of autism spectrum disorders:Revisiting gastrointestinal involvement and immune imbalance

Autism spectrum disorders(ASD)comprise a group of neurodevelopmental abnormalities that begin in early childhood and are characterized by impairment of social communication and behavioral problems including restricted interests and repetitive behaviors.Several genes have been implicated in the pathogenesis of ASD,most of them are involved in neuronal synaptogenesis.A number of environmental factors and associated conditions such as gastrointestinal(GI)abnormalities and immune imbalance have been linked to the pathophysiology of ASD.According to the March 2012 report released by United States Centers for Disease Control and Prevention,the prevalence of ASD has sharply increased during the recent years and one out of 88 children suffers now from ASD symptoms.Although there is a strong genetic base for the disease,several associated factors could have a direct link to the pathogenesis of ASD or act as modifiers of the genes thus aggravating the initial problem.Many children suffering from ASD have GI problems such as abdominal pain,chronic diarrhea,constipation,vomiting,gastroesophageal reflux,and intestinal infections.A number of studies focusing on the intestinal mucosa,its permeability,abnormal gut development,leaky gut,and other GI problem raised many questions but studies were somehow inconclusive and an expert panel of American Academy of Pediatrics has strongly recommended further investigation in these areas.GI tract has a direct connection with the immune system and an imbalanced immune response is usually seen in ASD children.Maternal infection or autoimmune diseases have been suspected.Activation of the immune system during early development may have deleterious effect on various organs including the nervous system.In this review we revisited briefly the GI and immune system abnormalities and neuropeptide imbalance and their role in the pathophysiology of ASD and discussed some future research directions.

Elaborately engineering of a dual-drug co-assembled nanomedicine for boosting immunogenic cell death and enhancing triple negative breast cancer treatment

Pure drug-assembled nanosystem provides a facile and promising solution for simple manufacturing of nanodrugs,whereas a lack of understanding of the underlying assembly mechanism and the inefficient and uncontrollable drug release still limits the development and application of this technology.Here,a simple and practical nanoassembly of DOX and DiR is constructed on basis of their co-assembly characteristics.Multiple interaction forces are found to drive the co-assembly process.Moreover,DOX release from the nanoassembly can bewell controlled by the acidic tumormicroenvironment and laser irradiation,resulting in favorable delivery efficiency of DiR and DOX in vitro and in vivo.As expected,the nanoassembly with high therapeutic safety completely eradicated the mice triple negative breast cancer cells(4T1)on BALB/c mice,owing to synergistic chemo-photothermal therapy.More interestingly,DiR and DOX synergistically induce immunogenic cell death(ICD)of tumor cells after treatment,enabling the mice to acquire immune memory against tumor growth and recurrence.Such a facile nanoassembly technique provides a novelmultimodal cancer treatment platform of chemotherapy/phototherapy/immunotherapy.

Human umbilical cord-derived mesenchymal stem cells promote repair of neonatal brain injury caused by hypoxia/ischemia in rats

Administration of human umbilical cord-derived mesenchymal stem cells(hUC-MSCs)is believed to be an effective method for treating neurodevelopmental disorde rs.In this study,we investigated the possibility of hUC-MSCs treatment of neonatal hypoxic/ischemic brain injury associated with maternal immune activation and the underlying mechanism.We established neonatal rat models of hypoxic/ischemic brain injury by exposing pregnant rats to lipopolysaccharide on day 16 or 17 of pregnancy.Rat offspring were intranasally administe red hUC-MSCs on postnatal day 14.We found that polypyrimidine tract-binding protein-1(PTBP-1)participated in the regulation of lipopolysaccharide-induced maternal immune activation,which led to neonatal hypoxic/ischemic brain injury.Intranasal delive ry of hUC-MSCs inhibited PTBP-1 expression,alleviated neonatal brain injury-related inflammation,and regulated the number and function of glial fibrillary acidic protein-positive astrocytes,there by promoting plastic regeneration of neurons and im p roving brain function.These findings suggest that hUC-MSCs can effectively promote the repair of neonatal hypoxic/ischemic brain injury related to maternal immune activation through inhibition of PTBP-1 expression and astrocyte activation.

Maternal Murine Cytomegalovirus Infection during Pregnancy Up-regulates the Gene Expression of Toll-like Receptor 2 and 4 in Placenta

Increasing evidence has revealed that maternal cytomegalovirus （CMV） infection may be associated with neurodevelopmental disorders in offspring. Potential relevance between the placental inflammation and CMV-related autism has been reported by clinical observation. Meanwhile, abnormal expression of Toll-like receptor 2 （TLR2） and TLR4 in placenta of patients with chorioamnionitis was observed in multiple studies. IL-6 and IL- 10 are two important maternal inflammatory mediators involved in neurodevelopmental disorders. To investigate whether murine CMV （MCMV） infection causes alterations in placental IL-6/10 and TLR2/4 levels, we analyzed the dynamic changes in gene expression of TLR2/4 and IL-6/10 in placentas following acute MCMV infection. Mouse model of acute MCMV infection during pregnancy was created, and pre-pregnant MCMV infected, lipopolysaccharide （LPS）-treated and uninfected mice were used as controls. At E13.5, E 14.5 and E 18.5, placentas and fetal brains were harvested and mRNA expression levels of placental TLR2/4 and IL-6/10 were analyzed. The results showed that after acute MCMV infection, the expression levels of placental TLR2/4 and IL-6 were elevated at E13.5, accompanied by obvious placental inflammation and reduction of placenta and fetal brain weights. However, LPS 50 ktg/kg could decrease the IL-6 expression at E13.5 and E14.5. This suggests that acute MCMV infection during pregnancy could up-regulate the gene expression of TLR2/4 in placental trophoblasts and activate them to produce more pro- inflammatory cytokine IL-6. High dose of LPS stimulation （50 gg/kg） during pregnancy can lead to down-regulation of IL-6 levels in the late stage. Imbalance of IL-6 expression in placenta might be associated with the neurodevelopmental disorders in progeny.

Survival,growth and immune activity of scallop Chlamys farreri cultured at different depths in Haizhou Bay(Yellow Sea,China) during hot season

Survival, growth and immune response of the scallop, Chlamys farreri, cultured in lantern nets at five different depths (2, 5, 10, 15, and 20 m below the sea surface) were studied in Haizhou Bay during the hot season (summer and autumn) of 2007. Survival and growth rates were quantified bimonthly. Immune activities in hemolymph (superoxide dismutase (SOD) and acid phosphatase (ACP)) were measured to evaluate the health of scallops at the end of the study. Environmental parameters at the five depths were also monitored during the experiment. Mortalities mainly occurred during summer. Survival of scallops suspended at 15 m (78.0%) and 20 m (86.7%) was significantly higher than at 2 m (62.9%), 5 m (60.8%) or 10 m (66.8%) at the end of the study. Mean shell height grew significantly faster at 10 m (205.0 μm/d) and 20 m (236.9 μm/d) than at 2, 5 or 15 m in summer (July 9 to September 1); however, shell growth rate at 20 m was significantly lower than at the other four depths in autumn (September 2 to November 6). In contrast to summer, scallops at 5 m grew faster (262.9 μm/d) during autumn. The growth of soft tissue at different depths showed a similar trend to the shell. Growth rates of shell height and soft tissue were faster in autumn than in summer, with the exception of shell height at 20 m. SOD activity of scallops increased with depth, and ACP activity was significantly higher at 15 and 20 m than at other depths, which suggests that scallops were healthier near the bottom. Factors explaining the depth-related mortality and growth of scallops are also discussed. We conclude that the mass mortality of scallop, C. farreri, during summer can be prevented by moving the culture area to deeper water and yield can be maximized by suspending the scallops in deep water during summer and then transferring them to shallow water in autumn.

Immune Killing Activity of Lymphocytes on Hela Cells Expressing Interleukin-12 In Vitro

The killing effects of lymphocytes on Hela cells expressing interleukin-12 （IL-12） in vitro were explored. By using gene transfection technique, full length IL-12 gene was transfected into Hela cells. The expression of IL-12 in Hela cells was detected quantitatively by ELISA; Changes in killing effects of lymphocytes on Hela cells expressing IL-12 were observed by MTT. It was found that Hela cells could express IL- 12 between 24 h and 72 h after transfection. Killing activity of lymphocytes on Hela cells expressing IL-12 was significantly enhanced. It was concluded by cell transfection technique, Hela cells could express 1L-12 and were more easily killed by lymphocytes.

Ultrasonic vocalizations in mice: relevance for ethologic and neurodevelopmental disorders studies

Mice use ultrasonic vocalizations(USVs)to communicate each other and to convey their emotional state.USVs have been greatly characterized in specific life phases and contexts,such as mother isolation-induced USVs for pups or female-induced USVs for male mice during courtship.USVs can be acquired by means of specific tools and later analyzed on the base of both quantitative and qualitative parameters.Indeed,different ultrasonic call categories exist and have already been defined.The understanding of different calls meaning is still missing,and it will represent an essential step forward in the field of USVs.They have long been studied in the ethological context,but recently they emerged as a precious instrument to study pathologies characterized by deficits in communication,in particular neurodevelopmental disorders(NDDs),such as autism spectrum disorders.This review covers the topics of USVs characteristics in mice,contexts for USVs emission and factors that modulate their expression.A particular focus will be devoted to mouse USVs in the context of NDDs.Indeed,several NDDs murine models exist and an intense study of USVs is currently in progress,with the aim of both performing an early diagnosis and to find a pharmacological/behavioral intervention to improve patients’quality of life.

Effects of Pseudoalteromonas sp. BC228 on Digestive Enzyme Activity and Immune Response of Juvenile Sea Cucumber(Apostichopus japonicus)

A marine bacterium, Pseudoalteromonas sp. BC228 was supplemented to feed in a feeding experiment aiming to determine its ability of enhancing the digestive enzyme activity and immune response of juvenile Apostichopus japonicus. Sea cucumber individuals were fed with the diets containing 0(control), 105, 107 and 109 CFU g-1 diet of BC228 for 45 days. Results showed that intestinal trypsin and lipase activities were significantly enhanced by 107 and 109 CFU g-1 diet of BC228 in comparison with control(P < 0.01). The phagocytic activity in the coelomocytes of sea cucumber fed the diet supplemented with 107 CFU g-1 diet of BC228 was significantly higher than that of those fed control diet(P < 0.05). In addition, 105 and 107 CFU g-1 diet of BC228 significantly enhanced lysozyme and phenoloxidase activities in the coelomic fluid of sea cucumber, respectively, in comparison with other diets(P < 0.01). Sea cucumbers, 10 each diet, were challenged with Vibrio splendidus NB13 after 45 days of feeding. It was found that the cumulative incidence and mortality of sea cucumber fed with BC228 containing diets were lower than those of animals fed control diet. Our findings evidenced that BC228 supplemented in diets improved the digestive enzyme activity of juvenile sea cucumber, stimulated its immune response and enhanced its resistance to the infection of V. splendidus.

Impact of the microenvironment on the pathogenesis of mucosaassociated lymphoid tissue lymphomas

Approximately 8%of all non-Hodgkin lymphomas are extranodal marginal zone B cell lymphomas of mucosa-associated lymphoid tissue(MALT),also known as MALT lymphomas.These arise at a wide range of different extranodal sites,with most cases affecting the stomach,the lung,the ocular adnexa and the thyroid.The small intestine is involved in a lower percentage of cases.Lymphoma growth in the early stages is associated with long-lasting chronic inflammation provoked by bacterial infections(e.g.,Helicobacter pylori or Chlamydia psittaci infections)or autoimmune conditions(e.g.,Sjögren’s syndrome or Hashimoto thyroiditis).While these inflammatory processes trigger lymphoma cell proliferation and/or survival,they also shape the microenvironment.Thus,activated immune cells are actively recruited to the lymphoma,resulting in either direct lymphoma cell stimulation via surface receptor interactions and/or indirect lymphoma cell stimulation via secretion of soluble factors like cytokines.In addition,chronic inflammatory conditions cause the acquisition of genetic alterations resulting in autonomous lymphoma cell growth.Recently,novel agents targeting the microenvironment have been developed and clinically tested in MALT lymphomas as well as other lymphoid malignancies.In this review,we aim to describe the composition of the microenvironment of MALT lymphoma,the interaction of activated immune cells with lymphoma cells and novel therapeutic approaches in MALT lymphomas using immunomodulatory and/or microenvironmenttargeting agents.

Self-oriented central-tumor delivery of legumain-cleavable vehicles governed by circulating monocyte/macrophage for precise tumor enrichment and immune activation

Compressed blood and intratumoral lymphatic vessels induced by proliferated tumor cells and elevated interstitial fluid pressure produce regional hypoxic and necrotic region within tumors,which severely reduced the accessibility of immunogenic cell death(ICD)related drugs and immune-related cells.Herein,the strategy of self-oriented deep tumor delivery by circulating monocyte/macrophage was proposed.Briefly,CS-AI including an indoleamine 2,3-dioxygenase(IDO)inhibitor indoximod(IND)and hydrophilic chitosan(CSO)linked with alanine-alanine-asparagine(AAN)was prepared,which could be selectively cleaved by legumain overexpressed in macrophages and promote the collapse in structure.Then,CS-AI was modified with mannose on the surface and further encapsulated the ICD inducer doxorubicin(DOX)to obtain M-CS-AI/DOX.Upon intravenous injection,MCS-AI/DOX was specially recognized and internalized by circulating monocyte in vivo.The formed drugs/monocyte tend to distribute in hypoxia/necrosis region guided by the homing signals released by tumor.Accumulated monocytes then further differentiated into macrophages,up-regulating the expression of legumain and promoting the sensitive-release of chemo-drug DOX,IND,and the mannose-modified CSO(M-CSO).The released IND would specifically regulate immunosuppressive tumor microenvironment,and synergistically inhibit tumor growth with immune activation elements,ICD-induced DOX,and the favorable adjuvant M-CSO.In summary,the self-oriented deep tumor delivery of legumain-cleavable nanovesicles through circulating monocyte makes it possible for reaching tumor regions inaccessible for nanoparticles and provides a novel insight for precise tumor enrichment and immune activation.