Chemoenzymatic Synthesis of Phosphosaccharides from Haemophilus parasuis Strains ER-6P (Serovar 15) and Nagasaki (Serovar 5).

Herein, we describe a chemoenzymatic and diversity-oriented approach for the first syntheses of octasaccharide repeating units of the capsular polysaccharides of Haemophilus parasuis serovar 15 and serovar 5. The synthetic method features efficient enzymatic assembly of sialyl galactose or N-acetyl-galactosamine building blocks, highly stereoselective chemical construction of α-type H-phosphonate, and the ß-stereospecific 1,3-glycosylation reaction of a rare sugar donor.

Chemical Evolution of Enzyme-Catalyzed Glycosylation.

ConspectusThe limited availability of structurally well-defined diverse glycans remains a major obstacle for deciphering biological functions as well as biomedical applications of carbohydrates. Despite tremendous progress that has been made in past decades, the synthesis of structurally well-defined complex glycans still represents one of the most challenging topics in synthetic chemistry. Chemical synthesis of glycans is a time-consuming and labor-intensive process that requires elaborate planning and skilled personnel. In contrast, glycosyltransferase-catalyzed enzymatic synthesis provides a more efficient, convenient, low-cost, and sustainable alternative to affording diverse and complex glycans. However, the existing methods are still insufficient to fulfill the increasing demand for specific synthetic glycan libraries necessary for functional glycomics research. This is mainly attributed to the inherent character of the glycan biosynthetic pathway. In nature, there are too many glycosyltransferases involved in the in vivo glycan synthesis, but only a small number of them are available for in vitro enzymatic synthesis. For instance, humans have over 200 glycosyltransferases, but only a few of them could be produced from the conventional bacterial expression system, and most of these membrane-associated enzymes could be overexpressed only in eukaryotic cells. Moreover, the glycan biosynthetic pathway is a nontemplate-driven process, which eventually ends up with heterogeneous glycan product mixtures. Therefore, it is not a practical solution for the in vitro enzymatic synthesis of complex glycans by simply copying the glycan biosynthetic pathway.In the past decade, we have tried to develop a simplified and transformable approach to the enzymatic modular assembly of a human glycan library. Despite the structural complexity of human glycans, the glycoinformatic analysis based on the known glycan structure database and the human glycosyltransferase database indicates that there are approximately 56 disaccharide patterns present in the human glycome and only 16 disaccharide linkages are required to account for over 80% of the total disaccharide fragments, while 35 disaccharide linkages are sufficient to cover over 95% of all disaccharide fragments of human glycome. Regardless of the substrate specificity, if one glycosyltransferase could be used for the synthesis of all of the same glycosidic linkages in human glycome, it will require only a few dozen glycosyltransferases for the assembly of entire human glycans. According to the glycobioinformatics analysis results, we rationally designed about two dozen enzyme modules for the synthesis of over 20 common glycosidic linkages in human glycome, in which each enzyme module contains a glycosyltransferase and a group of enzymes for the in situ generation of a nucleotide-activated sugar donor. By sequential glycosylation using orchestrated enzyme modules, we have completed the synthesis of over 200 structurally well-defined complex human glycans including blood group antigens, O-mannosyl glycans, human milk oligosaccharides, and others. To overcome the product microheterogeneity problem of enzymatic synthesis in the nontemplate-driven glycan biosynthetic pathway, we developed several substrate engineering strategies to control or manipulate the outcome of glycosyltransferase-catalyzed reactions for the precise synthesis of structurally well-defined isomeric complex glycans.

Aspirin inhibits rotavirus replication and alters rat gut microbial composition.

BACKGROUND: Aspirin is widely used to treat various clinical symptoms. Evidence suggests that aspirin has antiviral properties, but little is known about its specific effect against rotavirus. METHODS: MA104, Caco-2, and CV-1 cells were infected with rotavirus, and aspirin was added after 12 h. Viral mRNA and titer levels were measured by qRT-PCR and immunofluorescence assays. For in vivo validation, forty specific-pathogen-free SD rats were randomly divided into oral aspirin (ASP) groups and control (NC) groups. 16 S rRNA gene sequencing was performed to identify gut microbiota. After 6 months of continuous ASP/NC administration, the rats were infected with rotavirus. Fecal samples were collected over a 30-day time course, and viral levels were quantified. Proinflammatory cytokines/chemokine levels were measured by ELISA. RESULTS: Aspirin inhibited rotavirus infection in cell lines and in rats. The effects of aspirin on viral replication were associated with the alteration of gut microbiota composition by aspirin, including increased abundance of Firmicutes and decreased abundance of Bacteroidetes after aspirin treatment. Mechanistically, aspirin reduced IL-2 and IL-10 levels, and increased IRF-1 and COX-2 levels. Aspirin blocked rotavirus replication in vitro and in vivo, which might be related to effects on IRF-1, COX-2, chemokines, and gut microbial composition. CONCLUSION: These results indicate that long-term oral aspirin administration reduces rotavirus infection. Intestinal virus infection may be suppressed in elderly patients who take aspirin for a long time. The change of their Gut microbiota may lead to functional disorder of the intestinal tract, which may provide some reference for clinical adjuvant probiotics treatment.

Comparison of stigmatizing views towards COVID-19 and mental disorders among adolescent and young adult students in China.

Objective: Infectious diseases including COVID-19 and mental disorders are two of the most common health conditions associated with stigma. However, the comparative stigma of these two conditions has received less attention in research. This study aimed to compare the prevalence of stigmatizing views toward people with COVID-19 and mental disorders and the factors associated with these views, among a large sample of adolescent and young adult students in China. Methods: A total of 9,749 adolescents and young adults aged 15-24 years completed a survey on stigmatizing attitudes toward COVID-19 and mental disorders, as well as mental health-related factors, including general mental health status and symptoms of depression, anxiety, insomnia, and post-traumatic stress disorder (PTSD). Multivariable linear regression analyses were conducted to identify factors associated with stigmatizing views. Findings: The prevalence of COVID-19 and mental disorders-related stigma was 17.2% and 40.7%, respectively. COVID-19-related stigma scores were significantly higher among male students (ß = 0.025, p < 0.05), those without quarantine experience (ß = 0.035, p < 0.001), those with lower educational level (p < 0.001), those with lower family income (p < 0.01), and those with higher PTSD symptoms (ß = 0.045, p < 0.05). Mental disorder-related stigma scores were significantly higher among individuals with average and lower-than-average levels of family income (p < 0.01), depression symptoms (ß = 0.056, p < 0.001), anxiety symptoms (ß = 0.051, p < 0.001), and mental health problems (ß = 0.027, p < 0.05). Conclusion: The stigma of mental disorders is higher in the youth population than the stigma of COVID-19. Factors associated with stigmatizing attitudes toward people with COVID-19 and mental disorders varied across the youth. Stigma-reduction interventions among the youth should be targeted specifically to COVID-19 or mental disorders conditions.

A Redox-Controlled Substrate Engineering Strategy for Site-Specific Enzymatic Fucosylation.

Fucosylation is one of the most common modifications of oligo-N-acetyllactosamine (oligo-LacNAc) glycans. However, none of known fucosyltransferases (FucTs) could install the α1,3-linked fucose to the oligo-LacNAc substrates in a site-specific manner. Here, we report a facile and general redox-controlled substrate engineering strategy for the site-specific α1,3-fucosylation of complex glycans containing multiple LacNAc units. This strategy takes advantage of an operationally simple oxidation enzyme module by using galactose oxidase (GOase) to convert the LacNAc unit into oxidized C6'-aldehyde LacNAc sequence, which is not a good substrate for recombinant α1,3-FucT from Helicobacter pylori strain 26695 (Hpα1,3FucT), enabling the site-specific α1,3-fucosylation at intact LacNAc sites. The general applicability and robustness of this strategy were demonstrated by the synthesis of a variety of structurally well-defined fucosides of linear and branched O- and N-linked glycans.

Vegetation Classification and Distribution Patterns in the South Slope of Yarlung Zangbo Grand Canyon National Nature Reserve, Eastern Himalayas.

Yarlung Zangbo Grand Canyon National Nature Reserve has the most complete vertical vegetation belts in China. However, identification and distribution of vertical vegetation belts is still uncertain and in debate. To explore the above issues, 190 plots were surveyed within the reserve from 2019 to 2021. Based on the vegetation plot data, cluster analysis, ordination analysis, and biodiversity statistics were performed to reveal the structure of vertical vegetation belts-the driving factors of vegetation distribution-to describe the main biodiversity patterns. Five vertical vegetation belts were identified by clustering. NMDS ordination showed that the main factor of vegetation distribution is elevation. Based on the results of the analysis and previous literature, a new scheme of vertical vegetation belts in the south slope of the reserve was proposed. There was a lower montane seasonal rainforest belt (600-1100 m), a lower montane evergreen broadleaf forest belt (1100-1800 m), a middle montane semi-evergreen broadleaf forest belt (1800-2400 m), a subalpine evergreen needleleaf forest belt (2400-3800 m), a alpine shrubland and meadow belt (3800-4400 m), an alpine sparse vegetation belt (4400-4800 m), and a nival belt (4800-7782 m). Among them, the seasonal rainforest belts are the northernmost distribution of this type, and the semi-evergreen broadleaf forest belts exist only in the Eastern Himalayas. The study showed a unimodal pattern in plant species diversity, the peak of which is about 1900 m. The middle montane semi-evergreen broadleaf forest belt had the highest species diversity in the reserve. This study settled the issues regarding the vertical vegetation belts, the main drivers of vegetation and assessment of plant species diversity in the south slope of the Yarlung Zangbo Grand Canyon National Nature Reserve. It provides essential support for the management and conservation of these ecosystems in the reserve.

Synthesis and Immunological Evaluation of Pentamannose-Based HIV-1 Vaccine Candidates.

Dense glycosylation and the trimeric conformation of the human immunodeficiency virus-1 (HIV-1) envelope protein limit the accessibility of some cellular glycan processing enzymes and end up with high-mannose-type N-linked glycans on the envelope spike, among which the Man5GlcNAc2 structure occupies a certain proportion. The Man5GlcNAc2 glycan composes the binding sites of some potent broadly neutralizing antibodies, and some lectins that can bind Man5GlcNAc2 show HIV-neutralizing activity. Therefore, Man5GlcNAc2 is a potential target for HIV-1 vaccine development. Herein, a highly convergent and effective strategy was developed for the synthesis of Man5 and its monofluoro-modified, trifluoro-modified, and S-linked analogues. We coupled these haptens to carrier protein CRM197 and evaluated the immunogenicity of the glycoconjugates in mice. The serological assays showed that the native Man5 conjugates failed to induce Man5-specific antibodies in vivo, while the modified analogue conjugates induced stronger antibody responses. However, these antibodies could not bind the native gp120 antigen. These results demonstrated that the immune tolerance mechanism suppressed the immune responses to Man5-related structures and the conformation of glycan epitopes on the synthesized glycoconjugates was distinct from that of native glycan epitopes on gp120.

Analysis of the intestinal microbial community altered during rotavirus infection in suckling mice.

BACKGROUND: Rotavirus (RV) is a principal cause of diarrhea. However, there is a limited understanding regarding alteration of the gut microbial community structure and abundance during RV infection. This study was to characterize any potential associations between RV infection and the intestinal microbiota. METHODS: Suckling mice were divided into normal group (NC) and infected group (RV) randomly. All of the suckling mice were euthanized four days post-RV infection. The virus titer was counted as fluorescent focus assay, and viral load was quantified by QPCR. Five sucking mice were randomly selected from each RV group and NC group for sample collection and pathological analysis. Mixed intestinal contents of the colon and rectum were collected from all of the suckling mice. To investigate the detailed relationship between RV infection and intestinal microbiota, the composition and distribution of intestinal microbiota from suckling mice were first analyzed using 16S rRNA sequencing technology. RESULTS: The results of the pathological characteristics showed that vacuolar degeneration, vasodilation, hyperemia, and destruction of the intestinal epithelium were apparent in the RV group. Representative genera from Lactobacillus and Fusobacterium were enriched in the NC group, while the Enterococcus and Escherichia/Shigella genera were enriched in the RV group. Helicobacter, Alloprevotrlla, Brevundimonas, Paenibacillus, and Parabacteroides were completely undetectable in the RV group. The predicted intestinal flora metabolic function results showed that "carbohydrate metabolism" and "lipid metabolism" pathways were significantly enriched within the NC group. A significant difference has been observed in the gut microbiota composition between the two groups. CONCLUSIONS: Our results demonstrated a significant difference in the gut microbiota composition in RV-infected suckling mice as compared to the RV un-infected suckling mice group. This work may provide meaningful information regarding the bacterial genera changed during RV infection. Moreover, the changes in these bacteria may be related with the replication and pathogenesis of RV infection.

Enzymatic modular assembly of hybrid Lewis antigens.

The enzymatic synthesis of hybrid Lewis antigens including KH-1 (Lewis y-Lewis x-Lactose, Ley-Lex-Lac), Lewis a-Lewis x-Lactose (Lea-Lex-Lac), and Lewis b-Lewis x-Lactose (Leb-Lex-Lac) has been achieved using a facile enzymatic modular assembly strategy. Starting from a readily available tetrasaccharide, 3 complex hybrid Lewis antigens were achieved in over 40% total yields in less than 5 linear steps of sequential enzymatic glycosylation using 6 enzyme modules. The regio-selective fucosylation was achieved by simply controlling the donor-acceptor ratio. This strategy provides an easy access to these biologically important complex hybrid Lewis antigens at preparative scales.

Cancer Cell Preferential Penetration and pH-Responsive Drug Delivery of Oligorutin.

We report herein a novel delivery system, derived from the facile enzymatic synthesis of oligorutin (OR), for cancer cell targeting and pH-responsive drug delivery. In this study, we demonstrate that OR could preferentially penetrate cancer cells via the lipid raft-mediated endocytosis pathway, and cell membrane cholesterol was critical to the internalization of OR. The accumulation of OR in the tumor region was further confirmed by an in vivo biodistribution study. Considering the tumor-targeting property of OR, a pH-responsive drug delivery system (OR-BTZ) was developed by covalent conjugation of the catechol groups on OR with antitumor drug bortezomib (BTZ) through a pH-sensitive borate ester bond. OR-BTZ exerted cytotoxicity as well as inhibition of the migration and invasion to hepatoma carcinoma cells and showed no apparent cytotoxicity with liver normal cells. The OR-BTZs also presented significant therapeutic efficacy and low systematic toxicity in the murine hepatocellular carcinoma model. To our knowledge, this study presents the first attempt to exploit the potential of oligoflavonoids for cancer cell-targeted drug delivery and will motivate the development of flavonoids and their derivatives as a new type of biomaterials for tumor-targeted therapy.

Enzymatic modular synthesis and microarray assay of poly-N-acetyllactosamine derivatives.

A facile enzymatic modular assembly strategy for the preparative-scale synthesis of poly-N-acetyllactosamine (poly-LacNAc) glycans with varied lengths and designed sialylation and/or fucosylation patterns is described. These glycans were printed as a microarray to investigate their interactions with a panel of glycan binding proteins (GBPs). Binding affinities revealed that the avidity of GBPs could be largely affected by the length and the patterns of sialylation and fucosylation.

Chemoenzymatic Synthesis of O-Mannose Glycans Containing Sulfated or Nonsulfated HNK-1 Epitope.

The human natural killer-1 (HNK-1) epitope is a unique sulfated trisaccharide sequence presented on O- and N-glycans of various glycoproteins and on glycolipids. It is overexpressed in the nervous system and plays crucial roles in nerve regeneration, synaptic plasticity, and neuronal diseases. However, the investigation of functional roles of HNK-1 in a more complex glycan context at the molecular level remains a big challenge due to lack of access to related structurally well-defined complex glycans. Herein, we describe a highly efficient chemoenzymatic approach for the first collective synthesis of HNK-1-bearing O-mannose glycans with different branching patterns, and for their nonsulfated counterparts. The successful strategy relies on both chemical glycosylation of a trisaccharide lactone donor for the introduction of sulfated HNK-1 branch and substrate promiscuities of bacterial glycosyltransferases that can tolerate sulfated substrates for enzymatic diversification. Glycan microarray analysis with the resulting complex synthetic glycans demonstrated their recognition by two HNK-1-specific antibodies including anti-HNK-1/N-CAM (CD57) and Cat-315, which provided further evidence for the recognition epitopes of these antibodies and the essential roles of the sulfate group for HNK-1 glycan-antibody recognition.

Redox-Controlled Site-Specific α2-6-Sialylation.

The first bacterial α2-6-sialyltransferase cloned from Photobacterium damselae (Pd2,6ST) has been widely applied for the synthesis of various α2-6-linked sialosides. However, the extreme substrate flexibility of Pd2,6ST makes it unsuitable for site-specific α2-6-sialylation of complex substrates containing multiple galactose and/or N-acetylgalactosamine units. To tackle this problem, a general redox-controlled site-specific sialylation strategy using Pd2,6ST is described. This approach features site-specific enzymatic oxidation of galactose units to mask the unwanted sialylation sites and precisely controlling the site-specific α2-6-sialylation at intact galactose or N-acetylgalactosamine units.

Expansion and differentiation of human hepatocyte-derived liver progenitor-like cells and their use for the study of hepatotropic pathogens.

The study of pathophysiological mechanisms in human liver disease has been constrained by the inability to expand primary hepatocytes in vitro while maintaining proliferative capacity and metabolic function. We and others have previously shown that mouse mature hepatocytes can be converted to liver progenitor-like cells in vitro with defined chemical factors. Here we describe a protocol achieving efficient conversion of human primary hepatocytes into liver progenitor-like cells (HepLPCs) through delivery of developmentally relevant cues, including NAD + -dependent deacetylase SIRT1 signaling. These HepLPCs could be expanded significantly during in vitro passage. The expanded cells can readily be converted back into metabolically functional hepatocytes in vitro and upon transplantation in vivo. Under three-dimensional culture conditions, differentiated cells generated from HepLPCs regained the ability to support infection or reactivation of hepatitis B virus (HBV). Our work demonstrates the utility of the conversion between hepatocyte and liver progenitor-like cells for studying HBV biology and antiviral therapies. These findings will facilitate the study of liver diseases and regenerative medicine.

The extent of liver injury determines hepatocyte fate toward senescence or cancer.

It is well known that induction of hepatocyte senescence could inhibit the development of hepatocellular carcinoma (HCC). Until now, it is still unclear how the degree of liver injury dictates hepatocyte senescence and carcinogenesis. In this study, we investigated whether the severity of injury determines cell fate decisions between hepatocyte senescence and carcinogenesis. After testing of different degrees of liver injury, we found that hepatocyte senescence is strongly induced in the setting of severe acute liver injury. Longer-term, moderate liver injury, on the contrary did not result into hepatocyte senescence, but led to a significant incidence of HCC instead. In addition, carcinogenesis was significantly reduced by the induction of severe acute injury after chronic moderate liver injury. Meanwhile, immune surveillance, especially the activations of macrophages, was activated after re-induction of senescence by severe acute liver injury. We conclude that severe acute liver injury leads to hepatocyte senescence along with activating immune surveillance and a low incidence of HCC, whereas chronic moderate injury allows hepatocytes to proliferate rather than to enter into senescence, and correlates with a high incidence of HCC. This study improves our understanding in hepatocyte cell fate decisions and suggests a potential clinical strategy to induce senescence to treat HCC.

Chemoenzymatic Assembly of Mammalian O-Mannose Glycans.

O-Mannose glycans account up to 30 % of total O-glycans in the brain. Previous synthesis and functional studies have only focused on the core M3 O-mannose glycans of α-dystroglycan, which are a causative factor for various muscular diseases. In this study, a highly efficient chemoenzymatic strategy was developed that enabled the first collective synthesis of 63 core M1 and core M2 O-mannose glycans. This chemoenzymatic strategy features the gram-scale chemical synthesis of five judiciously designed core structures, and the diversity-oriented modification of the core structures with three enzyme modules to provide 58 complex O-mannose glycans in a linear sequence that does not exceed four steps. The binding profiles of synthetic O-mannose glycans with a panel of lectins, antibodies, and brain proteins were also explored by using a printed O-mannose glycan array.

Insulin-like growth factor 2 is a key mitogen driving liver repopulation in mice.

Hepatocyte transplantation holds great promise as an alternative to orthotopic organ transplantation in the treatment of liver diseases. However, obtaining clinically meaningful levels of liver repopulation has not been achieved because the mechanisms regulating hepatocyte proliferation in recipient livers have not yet been well characterized. In the mouse model of Hereditary Tyrosinemia Type I, the fumarylacetoacetate hydrolase-deficient (Fah-/-) mouse, we found gradually increasing expression level of insulin-like growth factor 2 (IGF2) in the hepatocytes of host livers. Similarly, high levels of IGF2 were found in the livers of patients with deficient FAH activity. Recombinant IGF2 directly promotes proliferation of primary hepatocytes in vitro. Inhibition on IGF2 expression through the interruption of PI3K/Akt and MAPK pathways significantly reduced the level of liver repopulation in Fah-/- mice. Interestingly, treatment with IGF2 before hepatocyte transplantation generally improved the amount of liver repopulation seen in various mice models of liver injury. Altogether, these findings underscore the underlying mechanisms of therapeutic liver repopulation in Fah-/- mice, and indicate that IGF2 is a potential hepatocyte mitogen for liver cell transplantation therapies.

Internalized stigma in people with severe mental illness in rural China.

BACKGROUND: It is unknown whether there are differences in self-stigma among persons with different types of severe mental illness (SMI) in rural communities. AIM: This study was to examine the differences of self-stigma and its correlates in persons with schizophrenia, major depressive disorder or bipolar disorder in a rural community in China. METHODS: A total of 453 persons with schizophrenia, major depressive disorder or bipolar disorder in a rural community participated in the study. The Internalized Stigma of Mental Illness (ISMI) was used to measure self-stigma. The t-test and analyses of variance (ANOVA) were used to examine the differences in mean scores of ISMI and subscales among the three diagnoses. Logistic regression was used to explore the contributing factors to the level of self-stigma among the three groups. RESULTS: Self-stigma was moderate and severe with 94.7% of the total sample. Persons with schizophrenia had significantly higher mean scores of total ISMI, alienation and discrimination experience than those with bipolar disorders. Lower family income was significantly associated with higher levels of self-stigma in persons with schizophrenia and major depressive disorder. Factors predicting the level of self-stigma among the three groups were various. CONCLUSION: Self-stigma is common and severe in persons with schizophrenia, major depressive disorder and bipolar disorder, especially those with lower income status in rural community in China. Persons with schizophrenia may have higher levels of self-stigma than those with bipolar disorder. Individual-level interventions should be developed to reduce self-stigma among persons with SMI in Chinese rural communities.

Surgical management of posterior knee dislocation associated with extensor apparatus rupture.

OBJECTIVE: The purpose of this study was to report the clinical and functional results of patients who underwent surgical management for posterior knee dislocation associated with extensor apparatus rupture. INTRODUCTION: Posterior knee dislocations associated with extensor apparatus ruptures are defined as rare but complicated injuries, which are difficult to return to the level of activity prior to the injury. The study demonstrated a hypothesis that good knee stability and early gain of range of motion could be achieved with deliberate design of the treatment protocol and proper application of the instruments. METHODS: Fifteen patients with posterior knee dislocations associated with extensor apparatus ruptures were evaluated after reduction and repair of extensor apparatus. Following that, multiple-ligament reconstruction in association with use of a lateral knee-spanning external fixator was applied for at least six weeks. Ligament reconstructions were performed using allografts. Range of motion and knee stability were both measured at each follow-up evaluation at a mean time of 36months. The assessment was made using the Lysholm Knee Scoring Scale. RESULTS: The mean Lysholm scale score was 87.6 (range 73-95), with excellent in 11 cases, good in two, and fair in two. In the final evaluation, the range of motion was a mean range of 123.4° (range 100-135). CONCLUSION: The use of a lateral knee-spanning external fixator ensured the safety of repaired vessels, knee stability after reduction, and early rehabilitation with range of motion.

A cancer vaccine based on fluorine-modified sialyl-Tn induces robust immune responses in a murine model.

Development of an effective vaccine to target tumor associated carbohydrate antigens, aberrantly expressed on the cell surface of various carcinomas, is an appealing approach toward cancer immunotherapy. However, a major problem of carbohydrate antigens is their poor immunogenicity. Immunization with modified-carbohydrate antigens could improve the immunogenicity and induce cross reaction with the native carbohydrate antigens. In this study, we investigated the antitumor ability of three fluoro-substituted sialyl-Tn (STn) analogues (2, 3, 4) coupled to KLH (keyhole limpet hemocyanin) and studied the mechanism of tumor immunotherapy of the vaccines in a murine model of colon cancer. Vaccination with 4-KLH, in which the two N-acetyl groups of STn are substituted with N-fluoroacetyl groups, could remarkably prolong the survival of tumor-bearing mouse and resulted in a significant reduction in tumor burden of lungs compared with STn-KLH (1-KLH). The vaccine 4-KLH could provoke stronger cytotoxic T lymphocytes immune response, T helper (Th) cell-mediated immune response and an earlier-stage Th1 immune response than 1-KLH, thus breaking immune tolerance and generating a therapeutic response. The 4-KLH vaccine induced strong tumor-specific anti-STn antibodies which could mediate complement-dependent cytotoxicity and antibody-dependent cell-mediated cytotoxicity against human tumor cells. Moreover, in the absence of adjuvant, 4-KLH still elicited stronger immune responses than 1-KLH. Our data suggested that 4-KLH is superior in tumor prevention. The strategic hapten fluorination may be a potential approach applicable to the vaccines development for the cancer immunotherapy.