An immunochromatographic strip sensor for marbofloxacin residues.

Marbofloxacin (MBF) was once widely used as a veterinary drug to control diseases in animals. MBF residues in animal food endanger human health. In the present study, an immunochromatographic strip assay (ICSA) utilizing a competitive principle was developed to rapidly detect MBF in beef samples. The 50% inhibitory concentration (IC50) and the limit of detection (LOD) of the ICSAs were 2.5 ng/mL and 0.5 ng/mL, respectively. The cross-reactivity (CR) of the MBF ICSAs to Ofloxacin (OFL), enrofloxacin (ENR), norfloxacin (NOR), and Ciprofloxacin (CIP) were 60.98%, 32.05%, 22.94%, and 23.58%, respectively. The CR for difloxacin (DIF) and sarafloxacin (SAR) was less than 0.1%. The recovery rates of MBF in spiked beef samples ranged from 82.0% to 90.4%. The intra-assay and interassay coefficients of variation (CVs) were below 10%. In addition, when the same authentic beef samples were detected in a side-by-side comparison between the ICSAs and HPLC‒MS, no statistically significant difference was observed. Therefore, the proposed ICSAs can be a useful tool for monitoring MBF residues in beef samples in a qualitative and quantitative manner.

Pathogen Identification: Ultrasensitive Nucleic Acid Detection via a Dynamic DNA Nanosystem-Integrated Ratiometric Electrochemical Sensing Strategy.

Sensitively determining trace nucleic acid is of great significance for pathogen identification. Herein, a dynamic DNA nanosystem-integrated ratiometric electrochemical biosensor was proposed to determine human immunodeficiency virus-associated DNA fragment (HIV-DNA) with high sensitivity and selectivity. The dynamic DNA nanosystem was composed of a target recycling unit and a multipedal DNA walker unit. Both of them could be driven by a toehold-mediated strand displacement reaction, enabling an enzyme-free and isothermal amplification strategy for nucleic acid determination. The target recycling unit could selectively recognize HIV-DNA and activate the multipedal DNA walker unit to roll on the electrode surface, which would lead to bidirectional signal variation for ratiometric readout with cascade signal amplification. Benefiting from the synergistic effect of the dynamic DNA nanosystem and the ratiometric output mode, the ultrasensitive detection of HIV-DNA was achieved in a wide linear range of 6 orders of magnitude with a limit of detection of 36.71 aM. The actual usability of the proposed sensor was also verified in complex biological samples with acceptable performance. This dynamic DNA nanosystem-integrated ratiometric sensing strategy might be promising in the development of reliable point-of-care diagnostic devices for highly sensitive and selective pathogen identification.

Probiotic as Adjuvant Significantly Improves Protection of the Lanzhou Trivalent Rotavirus Vaccine against Heterologous Challenge in a Gnotobiotic Pig Model of Human Rotavirus Infection and Disease.

This preclinical study in the gnotobiotic (Gn) pig model of human rotavirus (HRV) infection and disease evaluates the effect of probiotic Lactobacillus rhamnosus GG (LGG) as a mucosal adjuvant on the immunogenicity and cross-protective efficacy of the Lanzhou live oral trivalent (G2, G3, G4) vaccine (TLV, aka LLR3). Gn pigs were immunized with three doses of TLV with or without concurrent administration of nine doses of LGG around the time of the first dose of the TLV vaccination, and were challenged orally with the virulent heterotypic Wa G1P[8] HRV. Three doses of TLV were highly immunogenic and conferred partial protection against the heterotypic HRV infection. LGG significantly enhanced the intestinal and systemic immune responses and improved the effectiveness of protection against the heterotypic HRV challenge-induced diarrhea and virus shedding. In conclusion, we demonstrated the immune-stimulating effects of probiotic LGG as a vaccine adjuvant and generated detailed knowledge regarding the cross-reactive and type-specific antibody and effector B and T cell immune responses induced by the TLV. Due to the low cost, ease of distribution and administration, and favorable safety profiles, LGG as an adjuvant has the potential to play a critical role in improving rotavirus vaccine efficacy and making the vaccines more cost-effective.

IDO Vaccine Ablates Immune-Suppressive Myeloid Populations and Enhances Antitumor Effects Independent of Tumor Cell IDO Status.

The immunosuppressive tumor microenvironment (TME) does not allow generation and expansion of antitumor effector cells. One of the potent immunosuppressive factors present in the TME is the indoleamine-pyrrole 2,3-dioxygenase (IDO) enzyme, produced mainly by cancer cells and suppressive immune cells of myeloid origin. In fact, IDO+ myeloid-derived suppressor cells (MDSC) and dendritic cells (DC) tend to be more suppressive than their IDO- counterparts. Hence, therapeutic approaches that would target the IDO+ cells in the TME, while sparing the antigen-presenting functions of IDO- myeloid populations, are needed. Using an IDO-specific peptide vaccine (IDO vaccine), we explored the possibility of generating effector cells against IDO and non-IDO tumor-derived antigens. For this, IDO-secreting (B16F10 melanoma) and non-IDO-secreting (TC-1) mouse tumor models were employed. We showed that the IDO vaccine significantly reduced tumor growth and enhanced survival of mice in both the tumor models, which associated with a robust induction of IDO-specific effector cells in the TME. The IDO vaccine significantly enhanced the antitumor efficacy of non-IDO tumor antigen-specific vaccines, leading to an increase in the number of total and antigen-specific activated CD8+ T cells (IFNγ+ and granzyme B+). Treatment with the IDO vaccine significantly reduced the numbers of IDO+ MDSCs and DCs, and immunosuppressive regulatory T cells in both tumor models, resulting in enhanced therapeutic ratios. Together, we showed that vaccination against IDO is a promising therapeutic option for both IDO-producing and non-IDO-producing tumors. The IDO vaccine selectively ablates the IDO+ compartment in the TME, leading to a significant enhancement of the immune responses against other tumor antigen-specific vaccines.

Simvastatin Reduces Protection and Intestinal T Cell Responses Induced by a Norovirus P Particle Vaccine in Gnotobiotic Pigs.

Noroviruses (NoVs) are a leading cause of acute gastroenteritis worldwide. P particles are a potential vaccine candidate against NoV. Simvastatin is a cholesterol-reducing drug that is known to increase NoV infectivity. In this study, we examined simvastatin's effects on P particle-induced protective efficacy and T-cell immunogenicity using the gnotobiotic pig model of human NoV infection and diarrhea. Pigs were intranasally inoculated with three doses (100 µg/dose) of GII.4/VA387-derived P particles together with monophosphoryl lipid A and chitosan adjuvants. Simvastatin-fed pigs received 8 mg/day orally for 11 days prior to challenge. A subset of pigs was orally challenged with 10 ID50 of a NoV GII.4/2006b variant at post-inoculation day (PID) 28 and monitored for 7 days post-challenge. Intestinal and systemic T cell responses were determined pre- and postchallenge. Simvastatin abolished the P particle's protection and significantly increased diarrhea severity after NoV infection. Simvastatin decreased proliferation of virus-specific and non-specific CD8 T cells in duodenum and virus-specific CD4 and CD8 T cells in spleen and significantly reduced numbers of intestinal mononuclear cells in vaccinated pigs. Furthermore, simvastatin significantly decreased numbers of duodenal CD4+IFN-γ+, CD8+IFN-γ+ and regulatory T cells and total duodenal activated CD4+ and CD8+ T cells in vaccinated pigs pre-challenge at PID 28. Following challenge, simvastatin prevented the IFN-γ+ T cell response in spleen of vaccinated pigs. These results indicate that simvastatin abolished P particle vaccine-induced partial protection through, at least in part, impairing T cell immunity. The findings have specific implications for the development of preventive and therapeutic strategies against NoV gastroenteritis, especially for the elderly population who takes statin-type drugs.

BackSwipe: Back-of-device Word-Gesture Interaction on Smartphones.

Back-of-device interaction is a promising approach to interacting on smartphones. In this paper, we create a back-of-device command and text input technique called BackSwipe, which allows a user to hold a smartphone with one hand, and use the index finger of the same hand to draw a word-gesture anywhere at the back of the smartphone to enter commands and text. To support BackSwipe, we propose a back-of-device word-gesture decoding algorithm which infers the keyboard location from back-of-device gestures, and adjusts the keyboard size to suit the gesture scales; the inferred keyboard is then fed back into the system for decoding. Our user study shows BackSwipe is feasible and a promising input method, especially for command input in the one-hand holding posture: users can enter commands at an average accuracy of 92% with a speed of 5.32 seconds/command. The text entry performance varies across users. The average speed is 9.58 WPM with some users at 18.83 WPM; the average word error rate is 11.04% with some users at 2.85%. Overall, BackSwipe complements the extant smartphone interaction by leveraging the back of the device as a gestural input surface.

In-plasma-catalysis for NO x degradation by Ti3+ self-doped TiO2-x /γ-Al2O3 catalyst and nonthermal plasma.

In an attempt to realize the efficient treatment of NO x , a mixed catalyst of Ti3+ self-doped TiO2-x and γ-Al2O3 was constructed by reducing commercial TiO2. The degradation effect on NO x was evaluated by introducing the mixed catalyst into a coaxial dual-dielectric barrier reactor. It was found that the synthesized TiO2-x could achieve considerable degradation effects (84.84%, SIE = 401.27 J L-1) in a plasma catalytic system under oxygen-rich conditions, which were better than those of TiO2 (73.99%) or a single plasma degradation process (26.00%). The presence of Ti3+ and oxygen vacancies in TiO2-x resulted in a relatively narrow band gap, which contributed to catalyzing deeply the oxidation of NO x to NO2 - and NO3 - during the plasma-induced "pseudo-photocatalysis" process. Meanwhile, the TiO2-x showed an improved discharge current and promoted discharge efficiency, explaining its significant activation effect in the reaction. Reduced TiO2-x could achieve an impressive degradation effect in a long-time plasma-catalysis process, and still maintained its intrinsic crystal structure and morphology. This work provides a facile synthesis procedure for preparing Ti3+ self-doped TiO2-x with practical and scalable production potential; moreover, the novel combination with plasma also provides new insights into the low-temperature degradation of NO x .

NR4A1 Methylation Associated Multimodal Neuroimaging Patterns Impaired in Temporal Lobe Epilepsy.

DNA hypermethylation has been widely observed in temporal lobe epilepsy (TLE), in which NR4A1 knockdown has been reported to be able to alleviate seizure severity in mouse model, while the underlying methylation-imaging pathway modulated by aberrant methylation levels of NR4A1 remains to be clarified in patients with TLE. Here, using multi-site canonical correlation analysis with reference, methylation levels of NR4A1 in blood were used as priori to guide fusion of three MRI features: functional connectivity (FC), fractional anisotropy (FA), and gray matter volume (GMV) for 56 TLE patients and 65 healthy controls. Post-hoc correlations were further evaluated between the identified NR4A1-associated brain components and disease onset. Results suggested that higher NR4A1 methylation levels in TLE were related with impaired temporal-cerebellar and occipital-cerebellar FC strength, lower FA in cingulum (hippocampus), and reduced GMV in putamen, temporal pole, and cerebellum. Moreover, findings were also replicated well in both patient subsets with either right TLE or left TLE only. Particularly, right TLE patients showed poorer cognitive abilities and more severe brain impairment than left TLE patients, especially more reduced GMV in thalamus. In summary, this work revealed a potential imaging-methylation pathway modulated by higher NR4A1 methylation in TLE via data mining, which may impact the above-mentioned multimodal brain circuits and was also associated with earlier disease onset and more cognitive deficits.

Pre-existing immunity to influenza virus hemagglutinin stalk might drive selection for antibody-escape mutant viruses in a human challenge model.

The conserved region of influenza hemagglutinin (HA) stalk (or stem) has gained attention as a potent target for universal influenza vaccines1-5. Although the HA stalk region is relatively well conserved, the evolutionarily dynamic nature of influenza viruses6 raises concerns about the possible emergence of viruses carrying stalk escape mutation(s) under sufficient immune pressure. Here we show that immune pressure on the HA stalk can lead to expansion of escape mutant viruses in study participants challenged with a 2009 H1N1 pandemic influenza virus inoculum containing an A388V polymorphism in the HA stalk (45% wild type and 55% mutant). High level of stalk antibody titers was associated with the selection of the mutant virus both in humans and in vitro. Although the mutant virus showed slightly decreased replication in mice, it was not observed in cell culture, ferrets or human challenge participants. The A388V mutation conferred resistance to some of the potent HA stalk broadly neutralizing monoclonal antibodies (bNAbs). Co-culture of wild-type and mutant viruses in the presence of either a bNAb or human serum resulted in rapid expansion of the mutant. These data shed light on a potential obstacle for the success of HA-stalk-targeting universal influenza vaccines-viral escape from vaccine-induced stalk immunity.

Hapten Synthesis and the Development of an Ultrasensitive Indirect Competitive ELISA for the Determination of Diethylstilbestrol in Food Samples.

An ultrasensitive indirect competitive enzyme-linked immunosorbent assay (ic ELISA) using monoclonal antibodies (mAbs) was developed for the specific detection of diethylstilbestrol (DES) residues. To establish an ELISA based on mAbs, hapten diethylstilbestrol mono-carboxypropyl-ether (DES-MCPE) was chemically synthetized and then conjugated to bovine serum albumin (BSA) for immunization in mice. This ic ELISA was further optimized for DES determination. The sensitivity of the ic ELISA was found to be 0.49 µg/kg and the limit of detection was 0.075 µg/kg. DES residues in salmon meat and pork were tested with the recovery range from 74.0 to 85.2% and the coefficient of variation (CV) was less than 10%. Parallel analysis of DES samples from salmon meat showed comparable results from the ic ELISA with high-performance liquid chromatography. The ic ELISA provides a useful screening method for the quantitative detection of DES residues in animal-derived food.

Effect of acrylamide on glucose homeostasis in female rats and its mechanisms.

Acrylamide (AA), a food contaminant, caused islet remodeling and increased hepatic glycogen content in male rats, but the effect of AA on glucose homeostasis in female rats remains unclear. In this study, female SD rats were orally treated with 0, 15, or 30 mg/kg·bw AA for 3 weeks. The levels of fasting blood glucose (FBG), blood glucose after oral administration of glucose, plasma insulin and hepatic glycogen were measured. The histology of the pancreas was observed, and the transcription of key genes involved in glucose metabolism and insulin signaling in liver were determined. Compared with the control, exposure to 30 mg/kg·bw of AA significantly increased FBG level, reduced hepatic glycogen content and impaired glucose tolerance. Moreover, damaged islets were observed at 15 and 30 mg/kg·bw AA-exposed groups. In addition, AA exposure significantly promoted gluconeogenesis and glycogenolysis (up-regulation of pc, g6p and gp) and decreased glycolysis (down-regulation of gck and pfk). Alternations in these processes may be associated with decreased plasma insulin levels and inhibited insulin-regulated IRS/PI3K/Akt/Foxo1 signaling transduction under AA exposure. Overall, our findings demonstrated that AA disrupted glucose homeostasis and elevated FBG level in female rats possibly by interfering with glucose metabolism and hampering the physiological effect of insulin.

Rolling circle amplification-mediated in situ synthesis of palladium nanoparticles for the ultrasensitive electrochemical detection of microRNA.

Herein, an ultrasensitive and label-free electrochemical biosensor was developed for microRNA (miRNA) based on rolling circle amplification (RCA)-mediated palladium nanoparticles (PdNPs). The sensor was fabricated by immobilizing dual-functionalized hairpin probes onto an electrode. The specific recognition of target miRNA-21 by the hairpin probes could trigger the RCA reaction, which produced numerous guanine (G)-rich long single-stranded DNAs (ssDNAs). Based on the interaction of the PdII species with the nitrogen atoms of the G bases, these G-rich long ssDNAs served as specific templates in the in situ synthesis of massive PdNPs as electrochemical indicators. The formation of PdNPs was demonstrated to be exactly along the RCA products by high-resolution transmission electron microscopy. Using this cascade signal amplification strategy, the developed biosensor achieved a linear range of 50 aM-100 fM with an ultralow detection limit of 8.6 aM miRNA-21. Furthermore, the developed biosensor exhibited good selectivity, reproducibility, stability and satisfactory feasibility for miRNA-21 detection in human serum samples; this ensured significant potential of this biosensor in disease diagnosis and prognosis applications.

Efficient Phytase Secretion and Phytate Degradation by Recombinant Bifidobacterium longum JCM 1217.

Genetic engineering of probiotics, like bifidobacteria, may improve their microbial cell factory economy. This work designed a novel shuttle plasmid pBPES, which bears exogenous appA and is stable within Bifidobacterium longum JCM 1217. Cloning of three predicted promoters into pBPES proved that all of them drive appA expression in B. longum JCM 1217. Transformation of plasmids pBPES-tu and pBPES-groEL into B. longum JCM1217 resulted in much more phytase secretion suggests P tu and P groEL are strong promoters. Further in vitro and in vivo experiments suggested B. longum JCM 1217/pBPES-tu degrades phytate efficiently. In conclusion, the study screened two stronger promoters and constructed a recombinant live probiotic strain for effectively phytase secretion and phytate degradation in gut. The strategy used in the study provided a novel technique for improving the bioaccessibility of phytate and decreasing phosphorus excretion.

An augmented reality sign-reading assistant for users with reduced vision.

People typically rely heavily on visual information when finding their way to unfamiliar locations. For individuals with reduced vision, there are a variety of navigational tools available to assist with this task if needed. However, for wayfinding in unfamiliar indoor environments the applicability of existing tools is limited. One potential approach to assist with this task is to enhance visual information about the location and content of existing signage in the environment. With this aim, we developed a prototype software application, which runs on a consumer head-mounted augmented reality (AR) device, to assist visually impaired users with sign-reading. The sign-reading assistant identifies real-world text (e.g., signs and room numbers) on command, highlights the text location, converts it to high contrast AR lettering, and optionally reads the content aloud via text-to-speech. We assessed the usability of this application in a behavioral experiment. Participants with simulated visual impairment were asked to locate a particular office within a hallway, either with or without AR assistance (referred to as the AR group and control group, respectively). Subjective assessments indicated that participants in the AR group found the application helpful for this task, and an analysis of walking paths indicated that these participants took more direct routes compared to the control group. However, participants in the AR group also walked more slowly and took more time to complete the task than the control group. The results point to several specific future goals for usability and system performance in AR-based assistive tools.

A Lateral Flow Immunochromato-graphic Strip Test for Rapid Detection of Oseltamivir Phosphate in Egg and Chicken Meat.

A lateral flow immunochromatographic strip test (LFIST) based on a competitive format was developed for rapid and sensitive on-site detection of oseltamivir phosphate (OP) residues in poultry product. The sensitivity (half inhibitory concentration, IC50) of the LFIST in the detection of egg and chicken meat samples was confirmed to be 2.56 and 2.63 µg/kg, and the limit detection (LOD) value were 0.43 and 0.42 µg/kg, respectively. For intra-assay and inter-assay reproducibility, recoveries of OP spiked samples ranged between 82.8% and 91.2% with coefficients of variations (CV) less than 5.67% (intra-assay) and 6.52% (inter-assay). The performance of LFIST was comparable to high-performance liquid chromatography (HPLC) in a parallel testing of egg samples and chicken samples. LFIST takes less than 5 minutes, eliminates the dependency on professional personnel, and thus can be used as a surveillance tool for on-site detection of OP residues.

A lateral flow immunochromatographic strip test for rapid detection of hexoestrol in fish samples.

A lateral flow immunochromatographic strip test was developed for rapid and sensitive on-site detection of hexoestrol (HES) residues in fish samples with colloidal gold labelling of the anti-HES monoclonal antibody. The strip is composed of a sample pad, a conjugate reagent pad, an absorbent pad and a test membrane containing a control line and a test line. The sensitivity (half inhibitory concentration, IC50) of the strip in the detection of fish extract samples was confirmed to be 1.86 µg kg-1, and the limit of detection value was 0.62 µg kg-1. For intra-assay and inter-assay reproducibility, recoveries of HES-spiked samples ranged from 86.3% to 92.3% and 85.8% to 93.4%, coefficients of variation were 2.91-4.64% and 4.24-5.17%, respectively. High-performance liquid chromatography was employed to confirm the performance of the strip. The strip test takes less than 10 min, and thus provides a repaid method for on-site detection of HES residues.

Using an Augmented Reality Device as a Distance-based Vision Aid-Promise and Limitations.

SIGNIFICANCE: For people with limited vision, wearable displays hold the potential to digitally enhance visual function. As these display technologies advance, it is important to understand their promise and limitations as vision aids. PURPOSE: The aim of this study was to test the potential of a consumer augmented reality (AR) device for improving the functional vision of people with near-complete vision loss. METHODS: An AR application that translates spatial information into high-contrast visual patterns was developed. Two experiments assessed the efficacy of the application to improve vision: an exploratory study with four visually impaired participants and a main controlled study with participants with simulated vision loss (n = 48). In both studies, performance was tested on a range of visual tasks (identifying the location, pose and gesture of a person, identifying objects, and moving around in an unfamiliar space). Participants' accuracy and confidence were compared on these tasks with and without augmented vision, as well as their subjective responses about ease of mobility. RESULTS: In the main study, the AR application was associated with substantially improved accuracy and confidence in object recognition (all P < .001) and to a lesser degree in gesture recognition (P < .05). There was no significant change in performance on identifying body poses or in subjective assessments of mobility, as compared with a control group. CONCLUSIONS: Consumer AR devices may soon be able to support applications that improve the functional vision of users for some tasks. In our study, both artificially impaired participants and participants with near-complete vision loss performed tasks that they could not do without the AR system. Current limitations in system performance and form factor, as well as the risk of overconfidence, will need to be overcome.

Rice Bran and Probiotics Alter the Porcine Large Intestine and Serum Metabolomes for Protection against Human Rotavirus Diarrhea.

Human rotavirus (HRV) is a leading cause of severe childhood diarrhea, and there is limited vaccine efficacy in the developing world. Neonatal gnotobiotic pigs consuming a prophylactic synbiotic combination of probiotics and rice bran (Pro+RB) did not exhibit HRV diarrhea after challenge. Multiple immune, gut barrier protective, and anti-diarrheal mechanisms contributed to the prophylactic efficacy of Pro+RB when compared to probiotics (Pro) alone. In order to understand the molecular signature associated with diarrheal protection by Pro+RB, a global non-targeted metabolomics approach was applied to investigate the large intestinal contents and serum of neonatal gnotobiotic pigs. The ultra-high performance liquid chromatography-tandem mass spectrometry platform revealed significantly different metabolites (293 in LIC and 84 in serum) in the pigs fed Pro+RB compared to Pro, and many of these metabolites were lipids and amino acid/peptides. Lipid metabolites included 2-oleoylglycerol (increased 293.40-fold in LIC of Pro+RB, p = 3.04E-10), which can modulate gastric emptying, andhyodeoxycholate (decreased 0.054-fold in the LIC of Pro+RB, p = 0.0040) that can increase colonic mucus production to improve intestinal barrier function. Amino acid metabolites included cysteine (decreased 0.40-fold in LIC, p = 0.033, and 0.62-fold in serum, p = 0.014 of Pro+RB), which has been found to reduce inflammation, lower oxidative stress and modulate mucosal immunity, and histamine (decreased 0.18-fold in LIC, p = 0.00030, of Pro+RB and 1.57-fold in serum, p = 0.043), which modulates local and systemic inflammatory responses as well as influences the enteric nervous system. Alterations to entire LIC and serum metabolic pathways further contributed to the anti-diarrheal and anti-viral activities of Pro+RB such as sphingolipid, mono/diacylglycerol, fatty acid, secondary bile acid, and polyamine metabolism. Sphingolipid and long chain fatty acid profiles influenced the ability of HRV to both infect and replicate within cells, suggesting that Pro+RB created a protective lipid profile that interferes with HRV activity. Polyamines act on enterocyte calcium-sensing receptors to modulate intracellular calcium levels, and may directly interfere with rotavirus replication. These results support that multiple host and probiotic metabolic networks, notably those involving lipid and amino acid/peptide metabolism, are important mechanisms through which Pro+RB protected against HRV diarrhea in neonatal gnotobiotic pigs.

Effects of Racecadotril on Weight Loss and Diarrhea Due to Human Rotavirus in Neonatal Gnotobiotic Pigs (Sus scrofa domesticus).

Diarrheal disease is the second leading cause of death in children younger than 5 y, and the most common cause of acute watery diarrhea in young children worldwide is rotaviral infection. Medicines to specifically reduce diarrhea would be a desirable adjunctive treatment to supportive fluid therapy to decrease the mortality rate of diarrheal diseases. In this study, we evaluated the efficacy of an antisecretory drug, racecadotril, in treating human rotavirus (HRV)-induced diarrhea in a neonatal gnotobiotic pig model. In total, 27 gnotobiotic pigs were randomly assigned (n = 9 per group) to receive either racecadotril, chlorpromazine (positive-control drug), or PBS (mock treatment) after inoculation with HRV. Pigs were weighed daily and rectal swabs were collected to determine fecal consistency scores and virus shedding. Rotaviral infection was confirmed by ELISA and cell culture immunofluorescence. Overall, the racecadotril-treated pigs had less severe illness than either the chlorpromazine- or mock-treated groups; this conclusion was supported by the lower fecal-consistency scores, shorter duration of diarrhea, and significant gain in body weight during the course of the study of the racecadotril-treated pigs. Through its influence on decreasing intestinal hypersecretion, racecadotril was better able to control the clinical signs of rotaviral infection in the gnotobiotic pigs. These results lend support for using racecadotril as a treatment for rotaviral diarrhea.

Modeling human enteric dysbiosis and rotavirus immunity in gnotobiotic pigs.

BACKGROUND: Rotavirus vaccines have poor efficacy in infants from low- and middle-income countries. Gut microbiota is thought to influence the immune response to oral vaccines. Thus, we developed a gnotobiotic (Gn) pig model of enteric dysbiosis to study the effects of human gut microbiota (HGM) on immune responses to rotavirus vaccination, and the effects of rotavirus challenge on the HGM by colonizing Gn pigs with healthy HGM (HHGM) or unhealthy HGM (UHGM). The UHGM was from a Nicaraguan infant with a high enteropathy score (ES) and no seroconversion following administration of oral rotavirus vaccine, while the converse was characteristic of the HHGM. Pigs were vaccinated, a subset was challenged, and immune responses and gut microbiota were evaluated. RESULTS: Significantly more rotavirus-specific IFN-γ producing T cells were in the ileum, spleen, and blood of HHGM than those in UHGM pigs after three vaccine doses, suggesting HHGM induces stronger cell-mediated immunity than UHGM. There were significant correlations between multiple Operational Taxonomic Units (OTUs) and frequencies of IFN-γ producing T cells at the time of challenge. There were significant positive correlations between Collinsella and CD8+ T cells in blood and ileum, as well as CD4+ T cells in blood, whereas significant negative correlations between Clostridium and Anaerococcus, and ileal CD8+ and CD4+ T cells. Differences in alpha diversity and relative abundances of OTUs were detected between the groups both before and after rotavirus challenge. CONCLUSION: Alterations in microbiome diversity and composition along with correlations between certain microbial taxa and T cell responses warrant further investigation into the role of the gut microbiota and certain microbial species on enteric immunity. Our results support the use of HGM transplanted Gn pigs as a model of human dysbiosis during enteric infection, and oral vaccine responses.