Microsporidian EnP1 alters host cell H2B monoubiquitination and prevents ferroptosis facilitating microsporidia survival.

Microsporidia are intracellular eukaryotic pathogens that pose a substantial threat to immunocompromised hosts. The way these pathogens manipulate host cells during infection remains poorly understood. Using a proximity biotinylation strategy we established that microsporidian EnP1 is a nucleus-targeted effector that modifies the host cell environment. EnP1's translocation to the host nucleus is meditated by nuclear localization signals (NLSs). In the nucleus, EnP1 interacts with host histone H2B. This interaction disrupts H2B monoubiquitination (H2Bub), subsequently impacting p53 expression. Crucially, this inhibition of p53 weakens its control over the downstream target gene SLC7A11, enhancing the host cell's resilience against ferroptosis during microsporidian infection. This favorable condition promotes the proliferation of microsporidia within the host cell. These findings shed light on the molecular mechanisms by which microsporidia modify their host cells to facilitate their survival.

Overcoming research challenges: In vitro cultivation of Ameson portunus (Phylum Microsporidia).

Ameson portunus is an intracellular pathogen that infects marine crabs Portunus trituberculatus and Scylla paramamosain, causing significant economic losses. However, research into this important parasite has been limited due to the absence of an in vitro culture system. To address this challenge, we developed an in vitro cultivation model of A. portunus using RK13 cell line in this study. The fluorescent labeling assay indicated a high infection rate (∼60 %) on the first day post-infection and quantitative PCR (qPCR) detection demonstrated successful infection as early as six hours post-inoculation. Fluorescence in situ hybridization (FISH) and qPCR were used for the detection of A. portunus infected cells. The FISH probe we designed allowed detection of A. portunus in infected cells and qPCR assay provided accurate quantification of A. portunus in the samples. Transmission electron microscopy (TEM) images revealed that A. portunus could complete its entire life cycle and produce mature spores in RK13 cells. Additionally, we have identified novel life cycle characteristics during the development of A. portunus in RK 13 cells using TEM. These findings contribute to our understanding of new life cycle pathways of A. portunus. The establishment of an in vitro culture model for A. portunus is critical as it provides a valuable tool for understanding the molecular and immunological events that occur during infection. Furthermore, it will facilitate the development of effective treatment strategies for this intracellular pathogen.

Smart roofs featuring predictive control: An upgrade for mitigating precipitation extreme-induced pluvial floods.

In the face of escalating urban pluvial floods exacerbated by climate change, conventional roof systems fall short of effectively managing precipitation extremes. This paper introduces a smart predictive solution: the Smart Internal Drainage Roof (SIDR) system, which leverages forecasted data to enhance the mitigation of pluvial floods in Central Business District (CBD) areas. Unlike traditional approaches, SIDRs utilize a synergistic combination of Rule-based Control (RBC) and Model Predictive Control (MPC) algorithms, tailored to optimize the operational efficiency of both grey and green roofs. Within the examined 1.3 km2 area in Beijing, China, SIDRs, covering 11% of the site, decreased total flooded areas by 30%-50% and eliminated 60%-100% of high-risk zones during three actual events. Moreover, SIDRs streamlined outflow processes without extending discharge time and reduced flood duration at a high-risk underpass by more than half. The SIDR's distinct features, including a high control resolution of 5 min, integration with existing waterproofs, and advanced 2D dynamic runoff visualization, position it as a scalable and cost-efficient upgrade in urban flood resilience strategies.

New insights into the degradation mechanism and risk assessment of HFPO-DA by advanced oxidation processes based on activated persulfate in aqueous solutions.

Hexafluoropropylene oxide dimer acid (HFPO-DA) is widely used as a substitute for perfluorooctanoic acid (PFOA). HFPO-DA exhibits high water solubility and low adsorption potential, conferring significant fluidity in aquatic environments. Given that the toxicity of HFPO-DA is similar to PFOA, it is necessary to control its content in aquatic environments. Electrochemical and thermally-activated persulfates have been successfully used to degrade HFPO-DA, but UV-activated persulfates cannot degrade the compound. Given that research on degradation mechanisms is still incomplete and lacks kinetic research, the mechanism and kinetic calculations of oxidative degradation were studied in detail using DFT calculations. And the toxicity of HFPO-DA degradation intermediates and products was evaluated to reveal the feasibility of using advanced oxidation process (AOP) technology based on persulfate to degrade HFPO-DA in wastewater. The results showed that the committed step of HFPO-DA degradation was initiated by the electron transfer reaction of SO4•- radicals. This reaction is not spontaneous at room temperature and requires sufficient electrical or thermal energy to be absorbed from the external environment. The perfluoroalcohol produced during this reaction can subsequently undergo four possible reactions: H atom abstraction from alcohol groups by an OH radical; H atom abstraction by SO4•-; direct HF removal; and HF removal with water as the catalyst. The final degradation products of HFPO-DA mainly include CO2, CF3CF2COOH, CF3COOH, FCOOH and HF, which has been identified through previous experimental analysis. Ecotoxicity assessment indicates that degradation does not produce highly toxic intermediates, and that the final products are non-toxic, supporting the feasibility of persulfate-based AOP technologies.

IL-37bΔ1-45 suppresses the migration and invasion of endometrial cancer cells by targeting the Rac1/NF-κB/MMP2 signal pathway.

Endometrial carcinoma is one of the most common malignancies in the female reproductive system. Interleukin-37 (IL-37) is a newly discovered anti-inflammatory factor belonging to the IL-1 family. IL-37 has five different isoforms, and IL-37b is the most biologically functional subtype. In recent years, the protective roles of IL-37 in different cancers, including lung and liver cancers, have been successively reported. IL-37 also plays an important role in some gynecological diseases such as endometriosis, adenomyosis, and cervical cancer. However, the role and mechanism of IL-37b, especially the mature form of IL-37b, in endometrial carcinoma have not been elucidated. The present study demonstrated that IL-37 protein was downregulated in endometrial carcinoma cells compared with the control endometrium. IL-37b did not affect the proliferation and colony-forming ability of endometrial cancer cells. A mature form of IL-37b (IL-37bΔ1-45) effectively suppressed the migration and invasion of endometrial cancer cells by decreasing the expression of matrix metalloproteinase 2 (MMP2) via Rac1/NF-κB signal pathway. However, it did not affect epithelial-mesenchymal transition (EMT) or filamentous actin (F-actin) depolymerization of endometrial cancer cells. IL-37bΔ1-45 attenuated tumor metastasis in a peritoneal metastatic xenograft model of endometrial cancer. To sum up, these results suggested IL-37b could be involved in the pathogenesis of endometrial carcinoma and provide a novel target for the diagnosis and treatment of endometrial carcinoma.

Ubiquitin C-terminal hydrolase L1 promotes expression of programmed cell death-ligand 1 in non-small-cell lung cancer cells.

Programmed cell death-ligand 1 (PD-L1) expressed on cancer cells can cause immune escape of non-small-cell lung cancer (NSCLC). Elucidation of the regulatory mechanisms of the PD-L1 expression is a prerequisite for establishing new tumor immunotherapy strategies. Ubiquitin C-terminal hydrolase L1 (UCHL1) is a regulator of cellular signaling transduction that is aberrantly expressed in NSCLC. However, it is not known whether UCHL1 regulates the expression of PD-L1 in NSCLC cells. In the present study, we found that UCHL1 promotes the expression of PD-L1 in NSCLC cell lines. In addition, UCHL1 expressed in NSCLC cells inhibited activation of Jurkat cells through upregulation of PD-L1 expression in in vitro experiments. Moreover, UCHL1 upregulates PD-L1 expression through facilitating activation of the AKT-P65 signaling pathway. In conclusion, these results indicated that UCHL1 promoted PD-L1 expression in NSCLC cells. This finding implied that inhibition of UCHL1 might suppress immune escape of NSCLC through downregulation of PD-L1 expression in NSCLC cells.

TIPE2 inhibits the migration and invasion of endometrial cells by targeting ß-catenin to reverse epithelial-mesenchymal transition.

STUDY QUESTION: Do changes in tumor necrosis factor-α-induced protein 8 (TNFAIP8)-like 2 (TIPE2) levels in endometrium of patients with adenomyosis alter the proliferation, migration and invasion ability of endometrial cells? SUMMARY ANSWER: TIPE2 expression levels were low in eutopic and ectopic endometrium of adenomyosis patients, and TIPE2 inhibited the migration and invasion of endometrial cells, mainly by targeting ß-catenin, to reverse the epithelial-mesenchymal transition (EMT). WHAT IS KNOWN ALREADY: Adenomyosis is a benign disease, but it has some pathophysiological characteristics similar to the malignant tumor. TIPE2 is a novel negative immune regulatory molecule, and it also participates in the development of malignant tumors. STUDY DESIGN, SIZE, DURATION: Control endometrium (n = 48 women with non-endometrial diseases) and eutopic/ectopic endometrium from patients with adenomyosis (n = 50), human endometrial cancer cell lines, and primary endometrial cells from the eutopic endometrium of adenomyosis patients were used in the study. PARTICIPANTS/MATERIALS, SETTING, METHODS: The expression level of TIPE2 mRNA and protein in the eutopic/ectopic endometrial tissues of adenomyosis patients and control endometrium was determined by quantitative RT-PCR (qRT-PCR), western blot and immunohistochemistry. The effects of TIPE2 overexpression and knockdown on the proliferation, migration and invasion of endometrial cell lines and primary adenomyotic endometrial cells were determined using a cell counting kit-8, 5-ethynyl-2'-deoxyuridine assay, colony-forming assay, transwell migration assay and matrigel invasion assay. The expression of EMT-related markers and signal molecules was detected by western blot. The interaction between TIPE2 and ß-catenin was detected by co-immunoprecipitation and laser confocal microscopy. MAIN RESULTS AND THE ROLE OF CHANCE: The mRNA and protein expression levels of TIPE2 in the eutopic and ectopic endometrial tissues of adenomyosis patients were significantly downregulated compared with the control endometrium (P Ë‚ 0.01). TIPE2 could bind to ß-catenin and inhibit the nuclear translocation of ß-catenin, downregulate the expression of stromal cell markers, upregulate the expression of glandular epithelial cell markers, decrease the occurrence of epithelial-mesenchymal transition (EMT) and suppress the migration and invasion of endometrial cells (P Ë‚ 0.01). LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: In this study, the experiments were performed only in eutopic and ectopic endometrial tissues, endometrial cancer cell lines and primary adenomyotic endometrial cells. A mouse model of adenomyosis will be constructed to detect the effects of TIPE2 in vivo. WIDER IMPLICATIONS OF THE FINDINGS: These results suggest that TIPE2 is involved in the development of adenomyosis, which provides a potential new diagnostic and therapeutic strategy for the treatment of adenomyosis. STUDY FUNDINGS/COMPETING INTEREST(S): This present study was supported by grants from the National Natural Science Foundation of China (81471437, 81771554), Natural Science Foundation of Shandong (ZR2018MH013), Science and technology development plan provided by Health and Family Planning Committee in Shandong (2014-25). The authors declare that they have no conflicts of interest.

Mutation spectrum of COL1A1/COL1A2 screening by high-resolution melting analysis of Chinese patients with osteogenesis imperfecta.

High-resolution melting (HRM) analysis has been shown to be a time-saving method for the screening of genetic variants. To increase the precision of the diagnosis of osteogenesis imperfecta (OI), we used HRM to explore COL1A1/COL1A2 mutations in 87 Chinese OI patients and to perform population-based studies of the relationships between their genotypes and phenotypes. Peripheral blood samples were collected from the 87 non-consanguineous probands. The coding regions and exon boundaries of COL1A1/COL1A2 were detected by HRM and confirmed by Sanger sequencing. The functional effects of mutations were predicted through bioinformatic tools. Mutations were detected in 70.3% of familial cases and 40% of sporadic cases (p < 0.01). Compared with COL1A1 mutations, patients with COL1A2 mutations were more prone to severe phenotypes. Helical mutations (caused by substitution of the glycine within the Gly-X-Y triplet domain) were more likely to occur in patients with type III and IV (p < 0.05). Haploinsufficiency mutations (caused by frameshift, nonsense, and splice-site mutations) appeared more frequently in patients with type I (p < 0.05). Compared with the Sanger sequencing and whole exome sequencing (WES), HRM was found to reduce total costs by 78%- 80% in patients who had a positive HRM separate melting curve. Our findings suggest that HRM would greatly benefit small and understaffed hospitals and laboratories, and would facilitate the accurate diagnosis and early treatment of OI in remote and less developed regions.

Targeted exome sequencing identified a novel USH2A mutation in a Chinese usher syndrome family: a case report.

BACKGROUND: Usher syndrome is a disease with a heterogeneous phenotype and genotype. Our purpose was to identify the gene mutation in a Chinese family with Usher syndrome type 2 and describe the clinical features. CASE PRESENTATION: A 23-year-old man complained of a 10-year duration of nyctalopia and a 3-year decline in visual acuity of both eyes accompanied by congenital dysaudia. To clarify the diagnosis, the clinical symptoms were observed and analysed in combination with comprehensive ophthalmologic examinations as well as genetic analysis (targeted exome sequencing, TES). A typical clinical presentation of Usher syndrome of the fundus was found, including a waxy yellow-like disc, bone-spicule formations and retinal vessel stenosis. Optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) showed loss of the ellipsoid zone and a reduction in paracaval vessel density in both eyes. Genetic analysis identified a novel homozygous c.8483_8486del (p.Ser2828*) mutation in USH2A. The mutation resulted in premature termination of translation and caused the deletion of 19 fibronectin type 3 domains (FN3), transmembrane (TM) region and PDZ-binding motif domain, which play an important role in protein binding. After combining the clinical manifestations and genetic results, the patient was diagnosed with Usher syndrome type 2. CONCLUSION: We found a novel c.8483_8486del mutation in the USH2A gene through TES techniques. The results broaden the spectrum of mutations in Usher syndrome type 2 and suggest that a combination of clinical information and molecular diagnosis via TES could help Usher syndrome patients obtain a better diagnosis.

Cross-talk between TNF-α and IFN-γ signaling in induction of B7-H1 expression in hepatocellular carcinoma cells.

Clinical benefit from immunotherapy of B7-H1/PD-1 checkpoint blockade indicates that it is important to understand the regulatory mechanism of B7-H1 expression in cancer cells. As an adaptive response to the endogenous antitumor immunity, B7-H1 expression is up-regulated in HCC cells. B7-H1 expression is induced mainly by IFN-γ released from tumor-infiltrating T cells in HCC. In addition, HCC is a prototype of inflammation-related cancer and TNF-α is a critical component of inflammatory microenvironment of HCC. In the present study, we asked whether TNF-α can promote the expression of B7-H1 induced by IFN-γ in HCC cells. We found that JAK/STAT1/IRF1 was the primary pathway responsible for induction of B7-H1 expression by IFN-γ in human HCC cell lines. TNF-α and IFN-γ synergistically induced the expression of B7-H1 in the HCC cells. Moreover, the mechanism of the synergy was that TNF-α enhanced IFN-γ signaling by upregulating the expression of IFN-γ receptors. Furthermore, B7-H1 expression induced synergistically by TNF-α and IFN-γ in murine HCC cells facilitated tumor growth in vivo. Our findings suggest that TNF-α may enhance the adaptive immune resistance mediated by IFN-γ-induced B7-H1 in HCC cells.

Immunization with a DNA vaccine encoding Toxoplasma gondii Superoxide dismutase (TgSOD) induces partial immune protection against acute toxoplasmosis in BALB/c mice.

BACKGROUND: Toxoplasma gondii (T. gondii) is an obligate intracellular protozoan parasite that infects all warm-blooded animals including humans and causes toxoplasmosis. An effective vaccine could be an ideal choice for preventing and controlling toxoplasmosis. T. gondii Superoxide dismutase (TgSOD) might participate in affecting the intracellular growth of both bradyzoite and tachyzoite forms. In the present study, the TgSOD gene was used to construct a DNA vaccine (pEGFP-SOD). METHODS: TgSOD gene was amplified and inserted into eukaryotic vector pEGFP-C1 and formed the DNA vaccine pEGFP-SOD. Then the BALB/c mice were immunized intramuscularly with the DNA vaccine and those injected with pEGFP-C1, PBS or nothing were treated as controls. Four weeks after the last immunization, all mouse groups followed by challenging intraperitoneally with tachyzoites of T. gondii ME49 strain. RESULTS: Results showed higher levels of total IgG, IgG2α in the sera and interferon gamma (IFN-γ) in the splenocytes from pEGFP-SOD inoculated mice than those unvaccinated, or inoculated with either empty plasmid vector or PBS. The proportions of CD4+ T cells and CD8+ T cells in the spleen from pEGFP-SOD inoculated mice were significantly (p < 0.05) increased compared to control groups. In addition, the survival time of mice immunized with pEGFP-SOD was significantly prolonged as compared to the controls (p < 0.05) although all the mice died. CONCLUSION: The present study revealed that the DNA vaccine triggered strong humoral and cellular immune responses, and aroused partial protective immunity against acute T. gondii infection in BALB/c mice. The collective data suggests the SOD may be a potential vaccine candidate for further development.

Vaccination with toxofilin DNA in combination with an alum-monophosphoryl lipid A mixed adjuvant induces significant protective immunity against Toxoplasma gondii.

BACKGROUND: A widely prevalent disease, toxoplasmosis poses serious health threats to both humans and animals; therefore, development of an ideal DNA vaccine against Toxoplasma gondii is needed eagerly. The purpose of the present study is to assess the protective efficacy of a DNA vaccine encoding the T. gondii toxofilin gene (pEGFP-toxofilin). In addition, toxofilin DNA vaccine combined with the individual adjuvants, alum or monophosphoryl lipid A (MPLA), or a mixture of alum-MPLA adjuvant were screened for their ability to enhance antibody responses. METHODS: Using bioinformatics, we analyzed the gene and amino acid sequences of the toxofilin protein, recognizing and identifying several potential linear B and T helper (Th)-1 cell epitopes. BALB/c mice were immunized three times with either toxofilin DNA vaccine alone or in combination with the adjuvants such as alum, MPLA or an alum-MPLA mixture. The systemic immune response was evaluated by cytokine, the percentage of CD4 (+) and CD8 (+) T cells and specific antibody measurement. Two weeks after the last immunization, protective efficacy was evaluated by challenging intraperitoneally with 1 × 104 tachyzoites of T. gondii or intragastrically with 20 cysts of T. gondii PRU strain. RESULTS: All experimentally immunized mice developed strong humoral and cellular immune responses compared with the control groups. Moreover, by comparison with the non-adjuvant toxofilin DNA vaccine group, adding alum adjuvant to toxofilin DNA vaccine resulted in an increase in humoral response and a skewed Th2 response. However, the MPLA adjuvant with toxofilin DNA vaccine induced significantly enhanced humoral and Th1-biased immune responses. Importantly, the co-administration of alum-MPLA adjuvant in combination with the toxofilin DNA vaccine shifted the Th2 immune response to a Th1 response compared with the alum-toxofilin group, and elicited the strongest humoral and Th1 responses among all the groups. At the same time, a longer survival time and less cyst amounts against T. gondii infection were also observed in the alum-MPLA-toxofilin group in comparison with single or no adjuvant groups. CONCLUSIONS: Toxoplasma gondii toxofilin is a promising vaccine candidate that warrants further development. Co-administration of the alum-MPLA adjuvant mixture with DNA vaccine could effectively enhance immunogenicity and strongly skew the cellular immune response towards a Th1 phenotype.

Protection via a ROM4 DNA vaccine and peptide against Toxoplasma gondii in BALB/c mice.

BACKGROUND: Toxoplasma gondii (T. gondii) is an obligate intracellular protozoan parasite with a broad host range including most warm-blooded animals, including humans. T. gondii surface antigen 1 (SAG1) is a well-characterized T. gondii antigen. T. gondii expresses five nonmitochondrial rhomboid intramembrane proteases, TgROM1-5. TgROM4 is uniformly distributed on the surface of T. gondii and involved in regulating MIC2, MIC3, MIC6, and AMA1 during T. gondii invasion of host cells. Bioinformatics have predicted ROM4 B-cell and T-cell epitopes. Immunization strategy is also a key factor in determining the effectiveness of the immune response and has gained increasing attention in T. gondii vaccine research. In this study, we used a DNA prime-peptide boost vaccination regimen to assess the protective efficacy of various vaccination strategies using TgROM4. METHODS: We identified a polypeptide (YALLGALIPYCVEYWKSIPR) using a bioinformatics approach, and immunized mice using a DNA-prime and polypeptide-boost regimen. BALB/c mice were randomly divided into six groups, including three experimental groups (peptide, pROM4 and pROM4/peptide) and three control groups (PBS, pEGFP-C1 and pSAG1). Mice were then immunized intramuscularly four times. After immunization, IgG and cytokine productions were determined using enzyme-linked immunosorbent assays. The survival time of mice was evaluated after challenge with tachyzoites of T. gondii RH strain. Additionally, the number of cysts in the brain was determined after intragastric challenge with cysts of T. gondii PRU strain. RESULTS: Mice vaccinated with different immunization regimens (peptide, pROM4 and pROM4/peptide) elicited specific humoral and cellular responses, with high levels of IgG, IgG2a, and interferon (IFN)-γ. Moreover, IgG, IgG2a and IFN-γ levels were highest in the pROM4/peptide group. Immunized mice, especially those in the pROM4/peptide group, had prolonged survival times after challenge with tachyzoites and reduced numbers of brain cysts after infection compared with negative controls. CONCLUSION: A DNA prime-peptide boost regimen based on ROM4 elicited the highest level of humoral and cellular immune responses among immunization regimens, and may be a promising approach to increase the efficacy of DNA immunization.

DNA Vaccines Encoding Toxoplasma gondii Cathepsin C 1 Induce Protection against Toxoplasmosis in Mice.

Toxoplasma gondii cathepsin C proteases (TgCPC1, 2, and 3) are important for the growth and survival of T. gondii. In the present study, B-cell and T-cell epitopes of TgCPC1 were predicted using DNAstar and the Immune Epitope Database. A TgCPC1 DNA vaccine was constructed, and its ability to induce protective immune responses against toxoplasmosis in BALB/c mice was evaluated in the presence or absence of the adjuvant α-GalCer. As results, TgCPC1 DNA vaccine with or without adjuvant α-GalCer showed higher levels of IgG and IgG2a in the serum, as well as IL-2 and IFN-γ in the spleen compared to controls (PBS, pEGFP-C1, and α-Galcer). Upon challenge infection with tachyzoites of T. gondii (RH), pCPC1/α-Galcer immunized mice showed the longest survival among all the groups. Mice vaccinated with DNA vaccine without adjuvant (pCPC1) showed better protective immunity compared to other controls (PBS, pEGFP-C1, and α-Galcer). These results indicate that a DNA vaccine encoding TgCPC1 is a potential vaccine candidate against toxoplasmosis.

Sequence Variation in Superoxide Dismutase Gene of Toxoplasma gondii among Various Isolates from Different Hosts and Geographical Regions.

Toxoplasma gondii, an obligate intracellular protozoan parasite of the phylum Apicomplexa, can infect all warm-blooded vertebrates, including humans, livestock, and marine mammals. The aim of this study was to investigate whether superoxide dismutase (SOD) of T. gondii can be used as a new marker for genetic study or a potential vaccine candidate. The partial genome region of the SOD gene was amplified and sequenced from 10 different T. gondii isolates from different parts of the world, and all the sequences were examined by PCR-RFLP, sequence analysis, and phylogenetic reconstruction. The results showed that partial SOD gene sequences ranged from 1,702 bp to 1,712 bp and A + T contents varied from 50.1% to 51.1% among all examined isolates. Sequence alignment analysis identified total 43 variable nucleotide positions, and these results showed that 97.5% sequence similarity of SOD gene among all examined isolates. Phylogenetic analysis revealed that these SOD sequences were not an effective molecular marker for differential identification of T. gondii strains. The research demonstrated existence of low sequence variation in the SOD gene among T. gondii strains of different genotypes from different hosts and geographical regions.

Alpha-galactosylceramide enhances protective immunity induced by DNA vaccine of the SAG5D gene of Toxoplasma gondii.

BACKGROUND: Toxoplasmosis caused by the intracellular parasite Toxoplasma gondii (T. gondii) is a global epidemic parasitic disease. DNA vaccines play an important role in preventing the spread of toxoplasmosis. SAG family genes encoding particular surface proteins of T. gondii are the best candidates of DNA vaccine. As a member of SAG family genes, SAG5 gene has been proved to have better antigenic than SAG1. In addition, alpha-Galactosylceramide (α-GalCer) was used to be an adjuvant in malaria vaccine and received positive results. In this study, the effect of the DNA vaccine enhanced by α-GalCer was evaluated by immunizing BALB/c mice. METHODS: In the present study, SAG5D gene of T. gondii was cloned, sequenced, and biologically characterized. BALB/c mice were randomly divided into five groups, including three experimental groups (pEGFP-C1-SAG5D, α-GalCer and α-GalCer/pEGFP-C1-SAG5D) and two control groups (PBS and pEGFP-C1), and were immunized intramuscularly three times. The levels of IgG antibodies and cytokine productions in mouse sera were determined by enzyme-linked immunosorbent assays (ELISA). Two weeks after the last immunization, all mice were challenged intraperitoneally with 1 × 10(4) tachyzoites of T. gondii and the survival time of mice was recorded. RESULTS: A significant level of increase of IgG response against the soluble tachyzoite antigens (STAg) was detected by ELISA in experimental group. It revealed relatively high level of IFN-γ production by the spleen cells. There were higher productions of interleukin-4 (IL-4) in α-GalCer treated groups compared to control groups. Challenge experiment showed a longer survival period (11 days compared with 5 days in control) in SAG5D DNA vaccinated mice was found after a lethal challenge with T. gondii RH strain. CONCLUSIONS: The present study suggested that T. gondii SAG5D was a novel and positive DNA vaccine candidate against toxoplasmosis. In addition, the adjuvant (α-GalCer) enhanced the body's cellular immune response and prolonged the survival time of mice after challenge.

Protective Efficacy of a Novel DNA Vaccine with a CL264 Molecular Adjuvant against Toxoplasma gondii in a Murine Model.

Toxoplasmosis is a significant global zoonosis with devastating impacts, and an effective vaccine against toxoplasmosis for humans has not yet been developed. In this study, we designed and formulated a novel DNA vaccine encoding the inhibitor of STAT1 transcriptional activity (IST) of T. gondii utilizing the eukaryotic expression vector pEGFP-N1 for the first time, with CL264 being a molecular adjuvant. Following intramuscular injection of the vaccine into mice, the levels of antibodies and cytokines were assessed to evaluate the immune response. Additionally, mice were challenged with highly virulent RH-strain tachyzoites of T. gondii, and their survival time was observed. The results show that the levels of IgG in serum, the ratio of IgG2a/IgG1 and the levels of IFN-γ in splenocytes of mice were significantly higher in the pEGFP-TgIST group and the pEGFP-TgIST + CL264 group than in the control group. In addition, the proportion of CD4+/CD8+ T cells was higher in mice immunized with either the pEGFP-TgIST group (p < 0.001) or the pEGFP-TgIST + CL264 group (p < 0.05) compared to the three control groups. Notably, TgIST-immunized mice exhibited prolonged survival times after T. gondii RH strain infection (p < 0.05). Our findings collectively demonstrate that the TgIST DNA vaccine elicits a significant humoral and cellular immune response and offers partial protection against acute T. gondii infection in the immunized mice, which suggests that TgIST holds potential as a candidate for further development as a DNA vaccine.

Evaluation of protective immunity induced by a DNA vaccine encoding SAG2 and SRS2 against Toxoplasma gondii infection in mice.

Toxoplasma gondii is an important protozoan pathogen, which can cause severe diseases in the newborns and immunocompromised individuals. Developing an effective vaccine against Toxoplasma infection is a critically important global health priority. Immunofluorescence staining analysis revealed that TgSAG2 and TgSRS2 are membrane associated and displayed on the surface of the parasite. Immunizations with pBud-SAG2, pBud-SRS2 and pBud-SAG2-SRS2 DNA vaccines significantly increased the production of specific IgG antibodies. Immunization with pBud-SAG2-SRS2 elicited cellular immune response with higher concentrations of IFN-γ and IL-4 compared to the control group. Antigen-specific lymphocyte proliferations in the pBud-SRS2 and pBud-SAG2-SRS2 groups were significantly higher compared to that in the control group. Furthermore, 30 % of mice immunized with pBud-SAG2-SRS2 survived after the challenge infection with virulent T. gondii RH tachyzoites. This study revealed that immunization with pBud-SAG2-SRS2 induced potent immune responses, and has the potential as a promising vaccine candidate for the control of T. gondii infection.

Anti-Toxoplasma gondii effect of tylosin in vitro and in vivo.

BACKGROUND: Toxoplasma gondii is an important protozoan pathogen with medical and veterinary importance worldwide. Drugs currently used for treatment of toxoplasmosis are less effective and sometimes cause serious side effects. There is an urgent need for the development of more effective drugs with relatively low toxicity. METHODS: The effect of tylosin on the viability of host cells was measured using CCK8 assays. To assess the inhibition of tylosin on T. gondii proliferation, a real-time PCR targeting the B1 gene was developed for T. gondii detection and quantification. Total RNA was extracted from parasites treated with tylosin and then subjected to transcriptome analysis by RNA sequencing (RNA-seq). Finally, murine infection models of toxoplasmosis were used to evaluate the protective efficacy of tylosin against T. gondii virulent RH strain or avirulent ME49 strain. RESULTS: We found that tylosin displayed low host toxicity, and its 50% inhibitory concentration was 175.3 µM. Tylsoin also inhibited intracellular T. gondii tachyzoite proliferation, with a 50% effective concentration of 9.759 µM. Transcriptome analysis showed that tylosin remarkably perturbed the gene expression of T. gondii, and genes involved in "ribosome biogenesis (GO:0042254)" and "ribosome (GO:0005840)" were significantly dys-regulated. In a murine model, tylosin treatment alone (100 mg/kg, i.p.) or in combination with sulfadiazine sodium (200 mg/kg, i.g.) significantly prolonged the survival time and raised the survival rate of animals infected with T. gondii virulent RH or avirulent ME49 strain. Meanwhile, treatment with tylosin significantly decreased the parasite burdens in multiple organs and decreased the spleen index of mice with acute toxoplasmosis. CONCLUSIONS: Our findings suggest that tylosin exhibited potency against T. gondii both in vitro and in vivo, which offers promise for treatment of human toxoplasmosis.

DNA prime and peptide boost immunization protocol encoding the Toxoplasma gondii GRA4 induces strong protective immunity in BALB/c mice.

BACKGROUND: Toxoplasma gondii is a widespread intracellular parasite, which infects most vertebrate animal hosts and causes zoonotic infection in humans. Vaccine strategy remains a promising method for the prevention and control of toxoplasmosis. T. gondii GRA4 protein has been identified as a potential candidate for vaccine development. In our study, we evaluated the immune response induced by four different immunization vaccination strategies encoding TgGRA4. METHODS: BALB/c mice were intramuscularly (i.m.) immunized four times according to specific immunization schedules. Generally, mice in experimental groups were immunized with polypeptide, pGRA4, peptide/DNA, or DNA/peptide, and mice in the control groups were injected with PBS or pEGFP. After immunization, the levels of IgG antibodies and cytokine productions were determined by enzyme-linked immunosorbent assays (ELISA). The survival time of mice was also evaluated after challenge infection with the highly virulent T. gondii RH strain. RESULTS: The results showed that mice vaccinated with different immunization regimens (polypeptide, pGRA4, peptide/DNA, or DNA/peptide) elicited specific humoral and cellular responses, with high levels of total IgG, IgG2a isotype and gamma interferon (IFN-γ), which suggested a specific Th1 immunity was activated. After lethal challenge, an increased survival time was observed in immunized mice (11.8 ± 4.8 days) compared to the control groups injected with PBS or pEGFP (P < 0.05). Mice injected with PBS or pEGFP died within 8 days, and there was no significant difference in the protection level in two groups (P > 0.05). CONCLUSIONS: These results demonstrated that this DNA prime and peptide boost immunization protocol encoding the TgGRA4 can elicit the highest level of humoral and cellular immune responses compared to other immunized groups, which is a promising approach to increase the efficacy of DNA immunization.