Roles of carbon dioxide in the conversion of biomass or waste plastics.

Under the current trend of pursuing sustainable development and environmental protection, the important application of carbon dioxide (CO2) in the conversion process of biomass or waste plastics has become a research direction of concern. The goal of this conversion process is to achieve the efficient use of carbon dioxide, providing a process for the efficient use of biomass, and solving the environmental problems caused by plastics. Remarkable progress has been made in the study of the reaction of CO2 with other substances to produce methane, low-carbon hydrocarbons, methanol, formic acid, and its derivatives, as well as ethers, aldehydes, gasoline, low-carbon alcohols, and other chemicals. In this paper, the important role of CO2 in the conversion of alcohol, sugar, cellulose, and waste plastics was reviewed, with emphasis on the important applications of CO2 as a carbon source, reactant, reaction medium, enhancing agent, solvent, and carrier gas in the conversion of biomass or waste plastics and the basic insights of the reaction mechanism. The emerging CO2 new roles not only put forward the green application of CO2 but also have guiding significance for the utilization of biomass resources and the treatment of waste plastics.

Sustainable ammonia and amines from chitin.

Efforts are underway to explore alternative methods to the Haber-Bosch process for sustainable ammonia production, while the potential for ammonia extraction from natural nitrogenous biomass is under-exploited. Here, a synergistic catalytic strategy involving acid and modified Ru-based catalysts is communicated for the direct production of amines and ammonia from chitin. Phosphoric acid promotes the cleavage of ether bonds in biomass polymers and also serves to protect amino groups from being removed. Selective hydrogenation, deoxygenation, and amination can be achieved by controllably adjusting the ratio of Ru0/Run+. The utilization of nitrogen atoms in chitin can reach up to 95 % (21 % amines, 74 % ammonium), and the catalytic process is applicable to waste shrimp shells. This study demonstrates the possibility of efficient production of nitrogen-containing compounds from abundant biopolymers.

CAR-Macrophage Therapy Alleviates Myocardial Ischemia-Reperfusion Injury.

BACKGROUND: Given the growing acknowledgment of the detrimental effects of excessive myocardial fibrosis on pathological remodeling after myocardial ischemia-reperfusion injury (I/R), targeting the modulation of myocardial fibrosis may offer protective and therapeutic advantages. However, effective clinical interventions and therapies that target myocardial fibrosis remain limited. As a promising chimeric antigen receptor (CAR) cell therapy, whether CAR macrophages (CAR-Ms) can be used to treat I/R remains unclear. METHODS: The expression of FAP (fibroblast activation protein) was studied in mouse hearts after I/R. FAP CAR-Ms were generated to target FAP-expressing cardiac fibroblasts in mouse hearts after I/R. The phagocytosis activity of FAP CAR-Ms was tested in vitro. The efficacy and safety of FAP CAR-Ms in treating I/R were evaluated in vivo. RESULTS: FAP was significantly upregulated in activated cardiac fibroblasts as early as 3 days after I/R. Upon demonstrating their ability to engulf FAP-overexpressing fibroblasts, we intravenously administered FAP CAR-Ms to mice at 3 days after I/R and found that FAP CAR-Ms significantly improved cardiac function and reduced myocardial fibrosis in mice after I/R. No toxicities associated with FAP CAR-Ms were detected in the heart or other organs at 2 weeks after I/R. Finally, we found that FAP CAR-Ms conferred long-term cardioprotection against I/R. CONCLUSIONS: Our proof-of-concept study demonstrates the therapeutic potential of FAP CAR-Ms in alleviating myocardial I/R and potentially opens new avenues for the treatment of a range of heart diseases that include a fibrotic phenotype.

A novel AI-based diagnostic model for pertussis pneumonia.

It is still very difficult to diagnose pertussis based on a doctor's experience. Our aim is to develop a model based on machine learning algorithms combined with biochemical blood tests to diagnose pertussis. A total of 295 patients with pertussis and 295 patients with non-pertussis lower respiratory infections between January 2022 and January 2023, matched for age and gender ratio, were included in our study. Patients underwent a reverse transcription polymerase chain reaction test for pertussis and other viruses. Univariate logistic regression analysis was used to screen for clinical and blood biochemical features associated with pertussis. The optimal features and 3 machine learning algorithms including K-nearest neighbor, support vector machine, and eXtreme Gradient Boosting (XGBoost) were used to develop diagnostic models. Using univariate logistic regression analysis, 18 out of the 27 features were considered optimal features associated with pertussis The XGBoost model was significantly superior to both the support vector machine model (Delong test, P = .01) and the K-nearest neighbor model (Delong test, P = .01), with the area under the receiver operating characteristic curve of 0.96 and an accuracy of 0.923. Our diagnostic model based on blood biochemical test results at admission and XGBoost algorithm can help doctors effectively diagnose pertussis.

Experimental Validation of Comprehensive Calculation for High-Resolution Linear MALDI-TOF Mass Spectrometry.

This work discusses the effectiveness of the previously developed comprehensive calculation model to optimize linear MALDI-TOF mass spectrometers. The model couples space- and velocity-focusing to precisely analyze the flight-time distribution of ions and predict optimal experimental parameters for the highest mass resolving power. Experimental validation was conducted using a laboratory-made instrument to analyze CsI3 and angiotensin I ions in low to medium m/z range. The results indicate that the predicted optimal extraction voltage and delay were reasonably accurate and effective. In the low m/z range, the peak width obtained using optimal parameters reached the sub nanosecond range, corresponding to a mass resolving power of 10 000-17 000, or 20 000-34 000 if shot-to-shot random fluctuations were minimized by the dynamic data correction method. The observed optimal mass resolving power in the current experiment is 4.8-7.8 times that of commercial instruments. Practical limitations resulting in the gap between the observed and theoretical ultimate mass resolving power are discussed.

Macrophages suppress cardiac reprogramming of fibroblasts in vivo via IFN-mediated intercellular self-stimulating circuit.

Direct conversion of cardiac fibroblasts (CFs) to cardiomyocytes (CMs) in vivo to regenerate heart tissue is an attractive approach. After myocardial infarction (MI), heart repair proceeds with an inflammation stage initiated by monocytes infiltration of the infarct zone establishing an immune microenvironment. However, whether and how the MI microenvironment influences the reprogramming of CFs remains unclear. Here, we found that in comparison with cardiac fibroblasts (CFs) cultured in vitro, CFs that transplanted into infarct region of MI mouse models resisted to cardiac reprogramming. RNA-seq analysis revealed upregulation of interferon (IFN) response genes in transplanted CFs, and subsequent inhibition of the IFN receptors increased reprogramming efficiency in vivo. Macrophage-secreted IFN-ß was identified as the dominant upstream signaling factor after MI. CFs treated with macrophage-conditioned medium containing IFN-ß displayed reduced reprogramming efficiency, while macrophage depletion or blocking the IFN signaling pathway after MI increased reprogramming efficiency in vivo. Co-IP, BiFC and Cut-tag assays showed that phosphorylated STAT1 downstream of IFN signaling in CFs could interact with the reprogramming factor GATA4 and inhibit the GATA4 chromatin occupancy in cardiac genes. Furthermore, upregulation of IFN-IFNAR-p-STAT1 signaling could stimulate CFs secretion of CCL2/7/12 chemokines, subsequently recruiting IFN-ß-secreting macrophages. Together, these immune cells further activate STAT1 phosphorylation, enhancing CCL2/7/12 secretion and immune cell recruitment, ultimately forming a self-reinforcing positive feedback loop between CFs and macrophages via IFN-IFNAR-p-STAT1 that inhibits cardiac reprogramming in vivo. Cumulatively, our findings uncover an intercellular self-stimulating inflammatory circuit as a microenvironmental molecular barrier of in situ cardiac reprogramming that needs to be overcome for regenerative medicine applications.

Comparison of the immune response and protection against the experimental Toxoplasma gondii infection elicited by immunization with the recombinant proteins BAG1, ROP8, and BAG1-ROP8.

Toxoplasmosis is one of the most dangerous zoonotic diseases, causing serious economic losses worldwide due to abortion and reproductive problems. Vaccination is the best way to prevent disease; thus, it is imperative to develop a candidate vaccine for toxoplasmosis. BAG1 and ROP8 have the potential to become vaccine candidates. In this study, rTgBAG1, rTgROP8, and rTgBAG1-rTgROP8 were used to evaluate the immune effect of vaccines in each group by detecting the humoral and cellular immune response levels of BABL/c mice after immunization and the ability to resist acute and chronic infection with Toxoplasma gondii (T. gondii). We divided the mice into vaccine groups with different proteins, and the mice were immunized on days 0, 14, and 28. The protective effects of different proteins against T. gondii were analysed by measuring the cytokines, serum antibodies, splenocyte proliferation assay results, survival time, and number and diameter of brain cysts of mice after infection. The vaccine groups exhibited substantially higher IgG, IgG1, and IgG2a levels and effectively stimulated lymphocyte proliferation. The levels of IFN-γ and IL-2 in the vaccine group were significantly increased. The survival time of the mice in each vaccine group was prolonged and the diameter of the cysts in the vaccine group was smaller; rTgBAG1-rTgROP8 had a better protection. Our study showed that the rTgBAG1, rTgROP8, and rTgBAG1-rTgROP8 recombinant protein vaccines are partial but effective approaches against acute or chronic T. gondii infection. They are potential candidates for a toxoplasmosis vaccine.

Iron-overload-induced ferroptosis in mouse cerebral toxoplasmosis promotes brain injury and could be inhibited by Deferiprone.

Iron is a trace metal element that is essential for the survival of cells and parasites. The role of iron in cerebral toxoplasmosis (CT) is still unclear. Deferiprone (DFP) is the orally active iron chelator that binds iron in a molar ratio of 3:1 (ligand:iron) and promotes urinary iron excretion to remove excess iron from the body. The aims of this experiment were to observe the alterations in iron in brains with Toxoplasma gondii (T. gondii) acute infections and to investigate the mechanism of ferroptosis in CT using DFP. We established a cerebral toxoplasmosis model in vivo using TgCtwh3, the dominant strains of which are prevalent in China, and treated the mice with DFP at a dose of 75 mg/kg/d. Meanwhile, we treated the HT-22 cells with 100 µM DFP for half an hour and then infected cells with TgCtwh3 in vitro. A qRT-PCR assay of TgSAG1 levels showed a response to the T. gondii burden. We used inductively coupled plasma mass spectrometry, an iron ion assay kit, Western blot analysis, glutathione and glutathione disulfide assay kits, a malonaldehyde assay kit, and immunofluorescence to detect the ferroptosis-related indexes in the mouse hippocampus and HT-22 cells. The inflammatory factors interferon-γ, tumor necrosis factor-α, transforming growth factor-ß, and arginase 1 in the hippocampus and cells were detected using the Western blot assay. Hematoxylin and eosin staining, electron microscopy, and the Morris water maze experiment were used to evaluate the brain injuries of the mice. The results showed that TgCtwh3 infection is followed by the activation of ferroptosis-related signaling pathways and hippocampal pathological damage in mice. The use of DFP led to ferroptosis resistance and attenuated pathological changes, inflammatory reactions and T. gondii burden of the mice, prolonging their survival time. The HT-22 cells with TgCtwh3 activated the ferroptosis pathway and was inhibit by DFP in vitro. In TgCtwh3-infected cells, inflammatory response and mitochondrial damage were severe, but these effects could be reduced by DFP. Our study elucidates the mechanism by which T. gondii interferes with the host's iron metabolism and activates ferroptosis, complementing the pathogenic mechanism of CT and further demonstrating the potential value of DFP for the treatment of CT.

Toxoplasma gondii Reactivation Aggravating Cardiac Function Impairment in Mice.

BACKGROUND: Toxoplasma gondii (T. gondii) reactivation is common, especially among immunocompromised individuals, such as AIDS patients. The cardiac involvement associated with toxoplasmosis, however, is usually obscured by neurological deterioration. The aim of this study was to observe the alterations in cardiac functions in various landmark periods after infection and to assess whether reactivation more seriously damages the heart. METHODS: We established three infection models in mice using TgCtwh6, a major strain of T. gondii prevalent in China. The groups included an acute group, chronic latent group, and reactivation group. We evaluated the cardiac function impairment via H & E staining, Masson staining, echocardiography, myocardial enzyme profiles, and cardiac troponin, and detected the expression of inflammatory factors and antioxidant factors with Western blotting. Immunofluorescence was used to detect the expression of the macrophage marker F4/80. RESULTS: Our results showed that damage to the heart occurred in the acute and reactivation groups. Impaired cardiac function manifested as a decrease in heart rate and a compensatory increase in left ventricular systolic function. Serum levels of cardiac enzymes also increased dramatically. In the chronic phase, myocardial fibrosis developed, diastolic functions became severely impaired, inflammation persisted, and macrophage expression was slightly reduced. Ultimately, reactivation infection exacerbated damage to cardiac function in mice, potentially leading to diastolic heart failure. Macrophages were strongly activated, and myocardial fibrosis was increased. In addition, the antioxidant capacity of the heart was severely affected by the infection. CONCLUSIONS: Taken together, these results suggested that the reactivation of T. gondii infection could aggravate injury to the heart, which could be associated with a host-cell-mediated immune response and strong cytokine production by macrophages, thus representing a novel insight into the pathogenic mechanism of toxoplasmosis.

LFA-1/ ICAM-1 promotes NK cell cytotoxicity associated with the pathogenesis of ocular toxoplasmosis in murine model.

Ocular toxoplasmosis (OT) is one of the most common causes of posterior uveitis. However, the pathogenic mechanisms of OT have not been well elucidated. Here, we used C57BL/6 (B6) mice to establish OT by peroral infection with 20 cysts of the TgCtWh6 strain, and severe ocular damage was observed by histopathological analysis in the eyes of infected mice. RNA-sequencing results showed that infection with T. gondii increased the expression of the NK-mediated cytotoxicity gene pathway at Day 30 after ocular T. gondii infection. Both NK-cell and CD49a+ NK-cell subsets are increased in ocular tissues, and the expression levels of LFA-1 in NK cells and ICAM-1 in the OT murine model were upregulated upon infection. Furthermore, inhibition of the interaction between LFA-1 and ICAM-1 with lifitegrast, a novel small molecule integrin antagonist, inhibited the protein expression of LFA-1 and ICAM-1 in murine OT and NK cells, improved the pathology of murine OT and influenced the secretion of cytokines in the OT murine model. In conclusion, the interaction between LFA-1 and ICAM-1 plays a role in the early regulation of the CD49a+ NK-cell proportion in an OT murine model. LFA-1/ ICAM-1 may be a key molecule in the pathogenesis of OT, and may provide new insights for potential immunotherapy.

High-performance miniature linear time-of-flight mass spectrometry as an advantageous tool in a high mass-to-charge range.

A miniature matrix-assisted laser desorption/ionization linear time-of-flight mass spectrometer suitable for the high mass-to-charge (m/z) region is described. The instrument size is roughly 1/50th that of regular instruments, and detailed dimensions and experimental parameters were optimized based on the comprehensive calculation method to provide satisfactory mass resolving power. Observations showed that the performance is limited in the low m/z range and becomes comparable with that of regular instruments in the mid m/z range. In the high m/z range, the miniature instrument provides better mass resolving power and sensitivity than regular instruments, showing superior performance for microbial, protein conjugate, and polymer analyses.

Protective effects of ZIP8 on Toxoplasma gondii-induced acute hepatocyte injury in mice.

Toxoplasma gondii (T. gondii), as an intracellular protozoan parasite, has the potential to disturb the homeostasis of trace metal elements in host cells. Zinc (Zn) is one of those essential metals that is required for combating infection. Zinc cellular homeostasis is controlled by zinc membrane transporters, including efflux and influx transporters. One of the Zrt-Irt-like protein (ZIP) transporters, ZIP8, facilitates zinc influx into the cytosol. It was recently reported to play significant roles in facilitating Zn uptakes during infection. Here, we investigated the function of ZIP8 in host defense against T. gondii infection in cultured alpha mouse liver 12 (AML12) hepatocytes and mice, with loss of ZIP8 function. Herein, C57BL/6 J female wild-type (WT) and ZIP8-KD mice (Slc39a8 knockdown mice), that were infected with tachyzoites of ToxoDB#9(TgCtwh3), were used as a model of acute toxoplasmosis. AML12 hepatocytes were transfected with lentivirus (LV), with silenced ZIP8 expression. Finally, we observed the function of hepatocytes pretreated with ZnCl2 before TgCtwh3 infection in vivo and in vitro. In vivo, the levels of zinc ions and ZIP8 protein were upregulated after TgCtwh3 infection. ZIP8 knockdown exacerbated liver damage, further decreased antioxidant enzyme activity, promoted inflammatory mediator expression, and upregulated the rate of apoptosis. ZnCl2 pretreatment before TgCtwh3 infection improved liver injury, increased antioxidant enzyme activity, restrained the expression of inflammatory mediators, and decreased the rate of apoptosis. The results in vitro were almost the same as those in vivo. This study defines the function of ZIP8-dependent zinc in hepatocyte damage during intracellular pathogen infection. Reagents that regulate ZIP8 activity might be developed as therapeutics to protect the liver function of toxoplasmosis.

Central sterile supply department (CSSD) management quality sensitive index constructed by management mode under the guidance of key point control theory and its effect on CSSD management quality: a retrospective study.

BACKGROUND: The central sterile supply department (CSSD) ensures the quality of medical care and controls infection. The professional, standardized, and scientific management of the CSSD is prerequisite if a hospital is to realize sustainable development. Based on the management mode and under the guidance of key point control theory, this study developed the CSSD management quality sensitive index to analyze its effects on the management quality of the CSSD. METHODS: We conducted a retrospective analysis of 282 medical devices processed from January 2020 to June 2020 (the control group), and 280 medical devices sterilized from July 2020 to December 2020 (the observation group). The devices in the control group were cleaned and disinfected according to the conventional operation process, while the observation group used a management quality sensitive index that had been developed according to the management mode, as guided by the key point control theory, and managed by the CSSD. The sensitive indexes of the two groups before and after the intervention were recorded to evaluate the work quality of CSSD medical staff. RESULTS: After the intervention, the process indexes, such as the qualified rate of cleaning quality, qualified rate of assembly, qualified rate of labeling, and correct rate of sterilization, the qualification rate of the sterilization results, the rate of intact packaging, and the rate of intact instruments, the environmental status, packaging quality, cleaning quality, and equipment management scores of the observation group were significantly higher than those of the control group (P<0.05). The incidence of wet packaging in the observation group was significantly lower than that in the control group (P<0.05). The service quality indexes, such as the replenishment time, retrieval time and preparation time of goods, of the observation group were significantly shorter than those of the control group (P<0.05). CONCLUSIONS: The quality sensitive index constructed under the guidance of the key point control theory can be used to guide the quality management of the CSSD, improve the processing results of key points in key control processes, and improve the work quality and service quality of the medical staff.

Prediction of prognosis in sepsis patients by the SOFA score combined with miR-150.

BACKGROUND: The sequential organ failure assessment (SOFA) score, designed to evaluate sepsis-associated organ dysfunction in intensive care unit (ICU) patients, is associated with the prognosis of sepsis patients. MicroRNA-150 (miR-150) is one of the first miRs to be detected in patients with sepsis and other critical illnesses, and to have an association with the prognosis of critical illness and sepsis. OBJECTIVES: To assess the predictive value of the combination of the SOFA score and miR-150 levels for the prognosis of sepsis patients. MATERIAL AND METHODS: We retrospectively included 437 adult patients with sepsis who were divided into a death group (n = 138, 31.6%) and a survival group (n = 299, 68.4%), according to their survival status at the 28-day follow-up. Binary logistic regression was performed to identify independent associations. Receiver operator characteristic (ROC) curve was employed to assess the predictive values. The Z-test was used to compare the area under curve (AUC). RESULTS: Multivariate analysis demonstrated that miR-150 (odds ratio (OR): 0.549, 95% confidence interval (95% CI) [0.372, 0.826], p < 0.001), the SOFA score (OR: 1.216, 95% CI [1.039, 1.807], p = 0.008), age, procalcitonin (PCT), and septic shock were independently associated with 28-day mortality of sepsis patients following the adjustment for chronic renal failure, hypertension, diabetes mellitus, activated partial thromboplastin time (APTT), serum creatinine (SCr), blood urea nitrogen (BUN), and total bilirubin (TBil). The AUC of miR-150, the SOFA score and their combination in predicting the 28-day mortality of sepsis patients was 0.762 (standard error (SE): 0.023, 95% CI [0.717, 0.808]), 0.735 (SE: 0.025, 95% CI [0.687, 0.784]) and 0.886 (SE: 0.015, 95% CI [0.857, 0.916]), respectively. The AUC of their combined prediction was significantly greater than the independent prediction (0.886 compared to 0.762, Z = 4.516, p < 0.001; 0.886 compared to 0.735, Z = 5.179, p < 0.001). The sensitivity and specificity of combination prediction were 86.2% and 80.6%, respectively. CONCLUSIONS: The combination of the SOFA score and miR-150 could improve the prediction of prognosis in sepsis patients.

Differential expression of TgMIC1 in isolates of Chinese 1 Toxoplasma with different virulence.

BACKGROUND: The predominant genotype of Toxoplasma in China is the Chinese 1 (ToxoDB#9) lineage. TgCtwh3 and TgCtwh6 are two representative strains of Chinese 1, exhibiting high and low virulence to mice, respectively. Little is known regarding the virulence mechanism of this non-classical genotype. Our previous RNA sequencing data revealed differential mRNA levels of TgMIC1 in TgCtwh3 and TgCtwh6. We aim to further confirm the differential expression of TgMIC1 and its significance in this atypical genotype. METHODS: Quantitative real-time PCR was used to verify the RNA sequencing data; then, polyclonal antibodies against TgMIC1 were prepared and identified. Moreover, the invasion and proliferation of the parasite in HFF cells were observed after treatment with TgMIC1 polyclonal antibody or not. RESULTS: The data showed that the protein level of TgMIC1 was significantly higher in high-virulence strain TgCtwh3 than in low-virulence strain TgCtwh6 and that the invasion and proliferation of TgCtwh3 were inhibited by TgMIC1 polyclonal antibody. CONCLUSION: Differential expression of TgMIC1 in TgCtwh3 and TgCtwh6 may explain, at least partly, the virulence mechanism of this atypical genotype.

The effects of video based nursing education on perioperative anxiety and depression in patients with gastric cancer.

The purpose of this study was to determine the effect of video-based nursing education on perioperative anxiety and depression. A total of 128 patients scheduled for minimally invasive gastrectomy were randomly divided into intervention (n = 64) and control (n = 64) group. The. The anxiety and depression scores, systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) were assessed before the intervention, 1 h before surgery and 24 h after surgery. And the cortisol levels were measured before the intervention and 1 h before surgery. No significant difference was observed in baseline anxiety score, depression score, vital signs and cortisol level (P > 0.05). The anxiety level, depression level, SBP, DBP and HR of patients in intervention group was significantly lower than that in control group at 1 h before surgery and 24 hs after surgery (P < 0.05). The serum cortisol in the intervention group was also significantly lower than that in the control group 1 h before surgery (p < 0.001). Video-based nursing education was effective in decreasing the perioperative anxiety and depression of patients undergoing minimally invasive gastrectomy. It could also keep vital signs and serum cortisol levels in normal limits.

A Dynamic Data Correction Method for Enhancing Resolving Power of Integrated Spectra in Spectroscopic Analysis.

A dynamic data correction method embedded in the process of data acquisition improves spectral quality. The method minimizes the impact of random errors in spectroscopic measurements by correcting peak positions in every single-scan spectrum. The method is fast enough to facilitate online data correction. The integration of corrected spectra improves resolving power and signal-to-noise ratio. The correction method can apply to most analytical spectra. In mass spectrometry and Raman spectroscopy, observations show that it improved the average resolving power by roughly 40-150% and revealed unresolved spectral features.

Production and characterization of monoclonal antibodies against Toxoplasma gondii ROP18 with strain-specific reactivity.

The rhoptry kinase 18 of Toxoplasma gondii (TgROP18) has been identified as a key virulence factor that allows the parasite to escape from host immune defences and promotes its proliferation in host cells. Although much research is focused on the interaction between host cells and TgROP18, the development of monoclonal antibodies (mAbs) against TgROP18 has not been reported till date. To produce mAbs targeting TgROP18, two hybridomas secreting mAbs against TgROP18, designated as A1 and T2, were generated using cell fusion technology. The subtypes of the A1 and T2 mAbs were identified as IgG3 λ and IgM κ, and peptide scanning revealed that the core sequences of the antigenic epitopes were 180LRAQRRRSELVFE192 and 351NYFLLMMRAEADM363, respectively. The T2 mAb specifically reacted with both T. gondii type I and Chinese I, but not with T. gondii type II, Plasmodium falciparum or Schistosoma japonicum. Finally, the sequences of heavy chain and light chain complementarity-determining regions of T2 were amplified, cloned and characterized, making the modification of the mAb feasible in the future. The development of mAbs against TgROP18 would aid the investigation of the molecular mechanisms underlying the modulation of host cellular functions by TgROP18, and in the development of strategies to diagnose and treat Toxoplasmosis.

Inducible Nitric Oxide Synthase Is a Key Host Factor for Toxoplasma GRA15-Dependent Disruption of the Gamma Interferon-Induced Antiparasitic Human Response.

Although Toxoplasma virulence mechanisms targeting gamma interferon (IFN-γ)-induced cell-autonomous antiparasitic immunity have been extensively characterized in mice, the virulence mechanisms in humans remain uncertain, partly because cell-autonomous immune responses against Toxoplasma differ markedly between mice and humans. Despite the identification of inducible nitric oxide synthase (iNOS) as an anti-Toxoplasma host factor in mice, here we show that iNOS in humans is a pro-Toxoplasma host factor that promotes the growth of the parasite. The GRA15 Toxoplasma effector-dependent disarmament of IFN-γ-induced parasite growth inhibition was evident when parasite-infected monocytes were cocultured with hepatocytes. Interleukin-1ß (IL-1ß), produced from monocytes in a manner dependent on GRA15 and the host's NLRP3 inflammasome, combined with IFN-γ to strongly stimulate iNOS expression in hepatocytes; this dramatically reduced the levels of indole 2,3-dioxygenase 1 (IDO1), a critically important IFN-γ-inducible anti-Toxoplasma protein in humans, thus allowing parasite growth. Taking the data together, Toxoplasma utilizes human iNOS to antagonize IFN-γ-induced IDO1-mediated cell-autonomous immunity via its GRA15 virulence factor.IMPORTANCEToxoplasma, an important intracellular parasite of humans and animals, causes life-threatening toxoplasmosis in immunocompromised individuals. Gamma interferon (IFN-γ) is produced in the host to inhibit the proliferation of this parasite and eventually cause its death. Unlike mouse disease models, which involve well-characterized virulence strategies that are used by Toxoplasma to suppress IFN-γ-dependent immunity, the strategies used by Toxoplasma in humans remain unclear. Here, we show that GRA15, a Toxoplasma effector protein, suppresses the IFN-γ-induced indole-2,3-dioxygenase 1-dependent antiparasite immune response in human cells. Because NLRP3-dependent production of IL-1ß and nitric oxide (NO) in Toxoplasma-infected human cells is involved in the GRA15-dependent virulence mechanism, blocking NO or IL-1ß production in the host could represent a novel therapeutic approach for treating human toxoplasmosis.