A Novel Multiepitope Fusion Antigen as a Vaccine Candidate for the Prevention of Enterotoxigenic E. coli-Induced Calf Diarrhea.

Calf diarrhea caused by enterotoxigenic E. coli (ETEC) poses an enormous economic challenge in the cattle industry. Fimbriae and enterotoxin are crucial virulence factors and vaccine targets of ETEC. Since these proteins have complicated components with large molecular masses, the development of vaccines by directly expressing these potential targets is cumbersome Therefore, this study aimed to develop a multiepitope fusion antigen designated as MEFA by integrating major epitopes of FanC and Fim41a subunits and a toxoid epitope of STa into the F17G framework. The 3D modeling predicted that the MEFA protein displayed the epitopes from these four antigens on its surface, demonstrating the desired structural characteristics. Then, the MEFA protein was subsequently expressed and purified for mouse immunization. Following that, our homemade ELISA showed that the mouse antiserum had a consistent increase in polyclonal antibody levels with the highest titer of 1:217 to MEFA. Furthermore, the western blot assay demonstrated that this anti-MEFA serum could react with all four antigens. Further, this antiserum exhibited inhibition on ETEC adhesion to HCT-8 cells with inhibitory rates of 92.8%, 84.3%, and 87.9% against F17+, F5+, and F41+ ETEC strains, respectively. Additionally, the stimulatory effect of STa toxin on HCT-8 cells was decreased by approximately 75.3% by anti-MEFA serum. This study demonstrates that the MEFA protein would be an antigen candidate for novel subunit vaccines for preventing ETEC-induced diarrhea in cattle.

Active fractions from Jingfang Baidu Powder alleviate Klebsiella-induced Pneumonia by inhibiting TLR4/Myd88-ERK signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Jingfang Baidu Powder (JFBDP) is a classic traditional Chinese medicine prescription. Although Jingfang Baidu powder obtained a general consensus on clinical efficacy in treating pneumonia, there were many Chinese herbal drugs in formula, complex components, and large oral dosage, which brings certain obstacles to clinical application. AIM OF THE STUDY: Therefore, screening of the active fraction that exerts anti-pneumonia helps improve the pharmaceutical preparation, improve the treatment compliance of patients, and further contribute to the clinical application, and the screening of the new active ingredients with anti-pneumonia. The histopathological observation, real-time quantitative PCR, western blotting, and immunofluorescence were applied to evaluate the anti-pneumonia efficacy of active fractions from JFBDP. RESULTS: Three fractions from JFBDP inhibit the gene expression of IL-1ß, IL-10, CCL3, CCL5, and CCL22 in lung tissue infected by Klebsiella at various degrees, and presented a good dose-response relationship. JF50 showed stronger anti-inflammatory effects among three fractions including JF30, JF50, and JF75. Besides, JF50 significantly reduced the protein expression of TLR4 and Myd88 in lung tissue infected with Klebsiella, and it also significantly inhibited p-ERK and p-NF-κB p65. JF50 significantly inhibits the protein expression of Caspase 3, Caspase 8, and Caspase 9 in lung tissue infected with Klebsiella at the dose of 25 mg/kg and 50 mg/kg. CONCLUSION: JF50 improves lung pathological damage in Klebsiella pneumonia mice by inhibiting the TLR4/Myd88/NF-κB-ERK signaling pathway, and inhibiting apoptosis of lung tissue cells. These findings provide a reference for further exploring the active substance basis of Jingfang Baidu Powder in treating bacterial pneumonia.

Breastfeeding vs. breast milk transmission during COVID-19 pandemic, which is more important?

The catastrophic coronavirus disease 2019 (COVID-19) pandemic has raised many health questions, and whether breast milk from SARS-CoV-2 infected mothers may be a vector for SARS-CoV-2 transmission has become a hot topic of concern worldwide. Currently, there are extremely limited and conflicting data on the risk of infection in infants through breastfeeding. For this reason, we investigated almost all current clinical studies and systematically analyzed the presence of SARS-CoV-2 and antibodies in the breast milk of mothers infected with SARS-CoV-2, their effects on newborns, and the mechanisms involved. A total of 82 studies were included in this review, of which 66 examined the presence of SARS-CoV-2 in breast milk samples from mothers diagnosed with COVID-19, 29 reported results of antibody detection of SARS-CoV-2 in breast milk, and 13 reported both nucleic acid and antibody test results. Seventeen studies indicated the presence of detectable SARS-CoV-2 nucleic acid in breast milk samples, and only two studies monitored viral activity, both of which reported that infectious viruses could not be cultured from RNA-positive breast milk samples. All 29 studies indicated the presence of at least one of the three antibodies, IgA, IgG and IgM, in breast milk. Five studies indicated the presence of at least one antibody in the serum of breastfed newborns. No COVID-19-related deaths were reported in all 1,346 newborns. Our study suggests that direct breastfeeding does not pose an additional risk of infection to newborns and that breast milk is a beneficial source of anti-SARS-CoV-2 antibodies that provide passive immune protection to infants. In addition, direct breastfeeding would provide maternal benefits. Our review supports the recommendation to encourage direct breastfeeding under appropriate infection control guidelines. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/#myprospero, identifier: 458043.

Anti-tumor effect of Crocus sativus petals polysaccharides by reconstructing tumor microenvironment.

Two polysaccharides from Crocus sativus petals (PCSPs), PCSPA and PCSPB have been previously reported to possess the immunopotentiation activity and improve innate immunity in mice. In this study, PCSPB was evaluated for the anti-tumor activity and explored its immunological mechanisms based on tumor microenvironment (TME) using S180 sarcoma-bearing mice. Although PCSPB showed the lower toxicity to a series of tumor cells, it significantly and dose-dependently suppressed the growth of S180 sarcomas transplanted in mice. HE staining, immunohistochemical analysis, and TUNEL assay revealed that PCSPB significantly induced tumor cell necrosis, apoptosis, and vessel disruption in sarcoma tissues. Meanwhile, PCSPB markedly decreased the levels of inflammatory factors TGF-ß, IFN-γ, IL-10 and TNF-α and down-regulated the mRNA expression levels of TGF-ß and TNF-α in tumor tissues. Flow cytometric analysis showed that PCSPB significantly increased the proportion of CD8+ T cells and NK cells, but decreased that of regulatory T cells (Tregs), total myeloid-derived suppressor cells (MDSCs), and tumor-associated macrophages (TAMs) in sarcoma tissues. Furthermore, immunofluorescence assay demonstrated that PCSPB noteworthily reprogrammed TAMs from a tumorigenic M2 towards an antitumorigenic M1 phenotype in S180 tissues. These findings demonstrated that PCSPB might exert the anti-tumor activity by reconstructing TME and could act as an anti-tumor candidate with low toxicity.

Correlation between COVID-19 vaccination and diabetes mellitus: A systematic review.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is one of the current global public health threats and vaccination is the most effective tool to reduce the spread and decrease the severity of COVID-19. Diabetes is one of the important chronic diseases threatening human health and is a common comorbidity of COVID-19. What is the impact of diabetes on the immunization effect of COVID-19 vaccination? Conversely, does vaccination against COVID-19 exacerbate the severity of pre-existing diseases in patients with diabetes? There are limited and conflicting data on the interrelationship between diabetes and COVID-19 vaccination. AIM: To explore the clinical factors and possible mechanisms underlying the interaction between COVID-19 vaccination and diabetes. METHODS: We conducted a comprehensive search of PubMed, MEDLINE, EMBASE, and Reference Citation Analysis (https://www.referencecitationanalysis.com) online databases, and medRxiv and bioRxiv gray literature using the keywords "SARS-CoV-2", "COVID-19", "vaccine", "vaccination", "antibody", and "diabetes" individually or in combination, with a cut-off date of December 2, 2022. We followed inclusion and exclusion criteria and after excluding duplicate publications, studies with quantifiable evidence were included in the full-text review, plus three manually searched publications, resulting in 54 studies being included in this review. RESULTS: A total of 54 studies were included, from 17 countries. There were no randomized controlled studies. The largest sample size was 350963. The youngest of the included samples was 5 years old and the oldest was 98 years old. The included population included the general population and also some special populations with pediatric diabetes, hemodialysis, solid organ transplantation, and autoimmune diseases. The earliest study began in November 2020. Thirty studies discussed the effect of diabetes on vaccination, with the majority indicating that diabetes reduces the response to COVID-19 vaccination. The other 24 studies were on the effect of vaccination on diabetes, which included 18 case reports/series. Most of the studies concluded that COVID-19 vaccination had a risk of causing elevated blood glucose. A total of 12 of the 54 included studies indicated a "no effect" relationship between diabetes and vaccination. CONCLUSION: There is a complex relationship between vaccination and diabetes with a bidirectional effect. Vaccination may contribute to the risk of worsening blood glucose in diabetic patients and diabetic patients may have a lower antibody response after vaccination than the general population.

Antibacterial diarrhea effect and action mechanism of Portulaca oleracea L. water extract based on the regulation of gut microbiota and fecal metabolism.

BACKGROUND: Portulaca oleracea has served as food and folk medicine in many parts of the world for thousands of years. Portulaca oleracea extract (POE) was prepared from fresh plants. This study aims to evaluate the antibacterial diarrhea effect and explore the possible mechanism. RESULTS: POE was effective in reducing diarrhea rate, improving intestinal tissue, and reducing cytokines concentrations of interleukin (IL)-6, IL-10, IL-12 p40 and TNF-α in blood. Besides, the result of histological observation showed that the mucus layer thickness and crypt length in the POE-treated group was higher than that in the model group. The POE could significantly upregulate the protein expression of MUC2, occludin and ZO-1. 16S rRNA sequencing analysis showed that Parabacteroides, Clostridium and Muribaculaceae may be the key functional microflora of POE. The non-targeted metabolomics also suggested that the antibacterial diarrheal effects of P. oleracea may be attributed to the regulation of amino acid metabolism and composition of the gut microbiota. CONCLUSION: Portulaca oleracea has definite clinical efficacy against bacterial diarrhea and anti-inflammatory effects. Its regulation of gut microbiota and fecal metabolism may account for its antibacterial diarrhea and anti-inflammatory effects. © 2023 Society of Chemical Industry.

Carbon quantum dot fluorescent probe for labeling and imaging of stellate cell on liver frozen section below freezing point.

The targeted labeling imaging of stellate cells on liver frozen section by immunofluorescence is a very promising visualization technique to study the distribution of stellate cells in the liver. In this study, water soluble carbon quantum dots that can emit blue, green and yellow fluorescence are synthesized by the hydrothermal method, and their sizes are 3.2, 3.7, and 4.3 nm, respectively. The three carbon quantum dots have good fluorescence stability, and the quantum yields are 36.1%, 26.3% and 21%, respectively. When the mass fraction of KCl in the blue carbon quantum dot dispersion system is 13%, it still maintains the liquid state at -30 °C. The final fluorescent probe is obtained after the carbon quantum dots are coupled with the secondary antibody, spectral characterizations confirm that the conjugate probe still maintains protein immunoactivity and has good stability. Cell experiments prove that the probe has good biocompatibility, the rabbit anti-mouse Desmin antibody is used as the primary antibody, the results of cellular immunofluorescence imaging and flow cytometry show that the probe can specifically label hepatic stellate cell at -20 °C. The results of liver frozen section experiments show that hepatic stellate cell can be specifically targeted and labeled by the fluorescent probe. This labeling technology provides an important technical means for elucidating the structure and function of the liver at the cellular level, exploring the liver pathological change, and designing and developing drug.

Adjuvant activity of tubeimosides by mediating the local immune microenvironment.

Rhizoma Bolbostemmatis, the dry tuber of Bolbostemma paniculatum, has being used for the treatment of acute mastitis and tumors in traditional Chinese medicine. In this study, tubeimoside (TBM) I, II, and III from this drug were investigated for the adjuvant activities, structure-activity relationships (SAR), and mechanisms of action. Three TBMs significantly boosted the antigen-specific humoral and cellular immune responses and elicited both Th1/Th2 and Tc1/Tc2 responses towards ovalbumin (OVA) in mice. TBM I also remarkably facilitated mRNA and protein expression of various chemokines and cytokines in the local muscle tissues. Flow cytometry revealed that TBM I promoted the recruitment and antigen uptake of immune cells in the injected muscles, and augmented the migration and antigen transport of immune cells to the draining lymph nodes. Gene expression microarray analysis manifested that TBM I modulated immune, chemotaxis, and inflammation-related genes. The integrated analysis of network pharmacology, transcriptomics, and molecular docking predicted that TBM I exerted adjuvant activity by interaction with SYK and LYN. Further investigation verified that SYK-STAT3 signaling axis was involved in the TBM I-induced inflammatory response in the C2C12 cells. Our results for the first time demonstrated that TBMs might be promising vaccine adjuvant candidates and exert the adjuvant activity through mediating the local immune microenvironment. SAR information contributes to developing the semisynthetic saponin derivatives with adjuvant activities.

Simultaneous labeling and multicolor fluorescence imaging of multiple immune cells on liver frozen section by polychromatic quantum dots below freezing points.

A method for simultaneous labeling and multicolor fluorescence imaging of different hepatic immune cells below freezing point is established based on quantum dots. In the experiment, carbon quantum dots with emission wavelength of 435 nm, CdTe@CdS quantum dots at 542 nm and CdSe@ZnS quantum dots at 604 nm are synthesized respectively, it is found that when the mass fractions of KCl (as antifreeze) are 12 %, 14 %, and 12 %, respectively, the three quantum dot dispersion systems remain liquid state at -20 °C. After they are conjugated with the corresponding secondary antibodies, agarose gel electrophoresis, circular dichroism and capillary electrophoresis confirm the effectiveness of conjugation. By indirect immunofluorescence method, the above three quantum dot fluorescent probes are used to simultaneously and specifically target a variety of liver immune cells, and the multi-color simultaneous imaging of different liver immune cells is realized under the same excitation wavelength, it is found that hepatic macrophages are arranged radially in the liver, hepatic stellate cells present punctate distribution, and hepatic sinusoidal endothelial cells present circular distribution, which is consistent with the results of H&E staining and ultrathin section TEM. This study provides an important technical means for elucidating the structure and function of the liver.

Correlation between COVID-19 and hepatitis B: A systematic review.

BACKGROUND: There is growing evidence that patients with coronavirus disease 2019 (COVID-19) frequently present with liver impairment. Hepatitis B virus (HBV) remains a major public health threat in current society. Both severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and HBV can cause liver damage, and current findings on whether HBV infection increases disease severity in COVID-19 patients are inconsistent, and whether SARS-CoV-2 infection accelerates hepatitis B progression or leads to a worse prognosis in hepatitis B patients has not been adequately elucidated. AIM: To explore the complex relationship between COVID-19 and hepatitis B in order to inform the research and management of patients co-infected with SARS-CoV-2 and HBV. METHODS: An experienced information specialist searched the literature in the following online databases: PubMed, China National Knowledge Infrastructure, Google Scholar, Scopus, Wiley, Web of Science, Cochrane, and ScienceDirect. The literature published from December 2019 to September 1, 2022 was included in the search. We also searched medRxiv and bioRxiv for gray literature and manually scanned references of included articles. Articles reporting studies conducted in humans discussing hepatitis B and COVID-19 were included. We excluded duplicate publications. News reports, reports, and other gray literature were included if they contained quantifiable evidence (case reports, findings, and qualitative analysis). Some topics that included HBV or COVID-19 samples but did not have quantitative evidence were excluded from the review. RESULTS: A total of 57 studies were eligible and included in this review. They were from 11 countries, of which 33 (57.9%) were from China. Forty-two of the 57 studies reported abnormalities in liver enzymes, three mainly reported abnormalities in blood parameters, four indicated no significant liver function alterations, and another eight studies did not provide data on changes in liver function. Fifty-seven studies were retrospective and the total number of co-infections was 1932, the largest sample size was 7723, and the largest number of co-infections was 353. Most of the studies suggested an interaction between hepatitis B and COVID-19, while 12 studies clearly indicated no interaction between hepatitis B and COVID-19. Six of the 57 studies clearly reported HBV activation. Six studies were related to liver transplant patients. CONCLUSION: There is some association between COVID-19 and hepatitis B. Future high-quality randomized trials are needed to further elucidate the interaction between COVID-19 and hepatitis B.

Development of an autophagy activator from Class III PI3K complexes, Tat-BECN1 peptide: Mechanisms and applications.

Impairment or dysregulation of autophagy has been implicated in many human pathologies ranging from neurodegenerative diseases, infectious diseases, cardiovascular diseases, metabolic diseases, to malignancies. Efforts have been made to explore the therapeutic potential of pharmacological autophagy activators, as beneficial health effects from caloric restriction or physical exercise are linked to autophagy activation. However, the lack of specificity remains the major challenge to the development and clinical use of autophagy activators. One candidate of specific autophagy activators is Tat-BECN1 peptide, derived from Beclin 1 subunit of Class III PI3K complexes. Here, we summarize the molecular mechanisms by which Tat-BECN1 peptide activates autophagy, the strategies for optimization and development, and the applications of Tat-BECN1 peptide in cellular and organismal models of physiology and pathology.

Terminal deoxynucleotidyl transferase associated with split G-quadruplex/hemin deoxyribozyme amplification detection for various contaminants in milk based on pregnancy test strip platform.

Contaminant residue analysis in milk can provide essential assistance for safety quality and contamination level management of milk production, which is critical for safeguarding public health. In this study, the pregnancy test strip is employed to achieve multiple analytes detection based on the specific recognition of aptamer and terminal deoxynucleotidyl transferase associated with split G-quadruplex/hemin deoxyribozyme system. Through the subsequent enzyme catalyzed reaction, the detection signal can be further amplified to improve the sensitivity. The method does not need to assemble test strip, prepare and purify antibodies/haptens, nor design complex probe sequences. By coupling human chorionic gonadotrophin with DNA probes and combining magnetic separation technology, the targets can be determined via the test strip. Under the optimized conditions, the visual detection limits for mercury ion, bisphenol A, and penicillin are 1, 0.1 and 0.05 nM, respectively. The detection results show that the method displays good accuracy and practicability in spiked milk sample. The method presents a simple scheme, low cost as well as good design versatility, which demonstrates great application prospect for the sensitive, low-cost, and convenient detection of food matrices.

Structure, thermostability and magnetic properties of cubic Ce2-x Ti2O7 pyrochlore obtained via sol-gel preparation.

Lanthanum-based titanates have been attracting considerable interest by virtue of their structural operability and hence diverse physical properties. The preparation of lanthanum-based titanates with novel crystal structure is a fascinating task. In this work, we report the preparation of a cubic Ce2-x Ti2O7 pyrochlore using the sol-gel method. The crystal structure, thermostability and magnetism were studied via the temperature dependence of X-ray powder diffraction, X-ray photoelectron spectroscopy and magnetization measurements. It has been revealed that the as-prepared Ce2-x Ti2O7 pyrochlore possesses a cubic symmetry (space group: Fd3̄m), however there is an 18(1)% vacancy of Ce ions in the as-prepared samples. No distinct phase transition and thermal expansion anomaly were observed in the investigated temperature range from 300 K to 700 K. Intriguingly, lattice defects may favor the transformation of Ce valence from +3 to +4 and an unusual weak magnetic ordering state emerged up to 400 K. The persistence of magnetism at such high temperatures is rare and mysterious for cerium titanates. Our findings provide the possibility of adjusting the crystal structure and magnetic properties of cerium titanates, anticipated to the development of lanthanum-based oxides.

Immunological regulation of the active fraction from Polygonatum sibiricum F. Delaroche based on improvement of intestinal microflora and activation of RAW264.7 cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Polygonatum sibiricum, known as "Huangjing" in Chinese traditional medicine, of which functions include invigorating Qi and nourishing Yin, tonifying spleen and kidney, which are considered to replenish energy, and strengthen immunity. However, both the active components and mechanism of the immune-enhancing effect of Polygonatum sibiricum have not been clarified. AIM OF THE STUDY: To evaluate the immunoregulation effects of PSE30 (Polygonatum sibiricum ethanol 30) and PSE75 (Polygonatum sibiricum ethanol 75). The gut microbial and activation of RAW264.7 cells were also evaluated for exploring the mechanism of PSE75. MATERIALS AND METHODS: Female ICR mice were randomly divided into different groups, which were pretreated with 0.9% saline, Yupingfeng granules, different dosage of PSE30 or PSE75. And the immunosuppressed mice model was constructed using cyclophosphamide. And the total duration of the experiment was 15 d. After that, the serum Immunoglobulins G (IgG) and Immunoglobulins M (IgM) antibody, regular blood testing, assessment of natural killer cell activity, and histological observation of spleen in immunosuppressed mice were measured to evaluate the immunoregulation effects of PSE30 and PSE75. Besides, effects of PSE75 on gut microbial were evaluated using 16s rRNA sequence. And the mRNA expression and cytokine secretion of RAW264.7 cell were evaluated to analyze the immunoregulation mechanism of PSE75. RESULTS: The content of serum IgG, IgM was significantly elevated by PSE75 (P＜0.05, P＜0.001). The NK cells killing activity in splenocytes against K562 cells induced by PSE30, and PSE75 was pronounced higher than that of the model group (P < 0.05). Both mRNA expression of Th1 molecular markers including interleukin (IL)-2, interferon (IFN)-γ, and signal transducers and activators of transcription (STAT) 4, and Th2 molecular markers including IL-4 in splenocytes were markedly enhanced by PSE30, and PSE75 (P < 0.05, P < 0.01, or P < 0.001). Besides, the result of 16s rRNA sequence indicated that PSE75 could recover the gut microbial community disturbed by cyclophosphamide. PSE75 could markedly promote the secretion of IL-6, IL-10, and IL-12 p40 from RAW264.7 cell (P＜0.01, or P＜0.001). CONCLUSIONS: PSE75 was proved to be a more promising immunomodulation agent, of which may enhance the immunity of immunosuppressed mice by improving gut microbial and activating macrophages. And PSE75 could be developed as a good immune booster in the future.

A simple fluorescent strategy for liver capillary labeling with carbon quantum dot-lectin nanoprobe.

Taking the hepatic sinusoid (HS) as the main delivery area of liver nutrients and metabolic waste, recognizing its structure is important for a deep understanding of liver function. In this paper, based on lycopersicon esculentum lectin (LEL), with targeting ability for endothelial cells, and carbon quantum dots (CQDs), with high biosafety, an LEL-coupled CQD immunofluorescence probe (CQD@LEL) that can label microvessels is designed and used for the fluorescence labeling and imaging of HS in liver tissue sections. The CQD size is approximately 2 nm. Blue fluorescence is emitted under excitation; its optimal excitation wavelength is 400 nm while the emission is at about 450 nm. Gel electrophoresis and capillary electrophoresis confirm that glutaraldehyde can couple LEL to CQD, and the obtained CQD@LEL retains the fluorescence property and has good stability. Optimization experiments show that its labeling effect is positively correlated with time and probe concentration for dyeing the blood vessels of mouse liver slices. In order to improve the effect further, a probe concentration of 0.17 mg mL-1 and incubation time of 3 h were chosen to label the liver tissue sections. The results show that the liver microvessels are formed by interstitial structures among the hepatic cords, and the HS presents a granular or patchy appearance. H&E and ultrathin section TEM show that the microvascular wall of the liver is composed of discontinuous endothelial cells, and there are Kupffer cells and other cells in the tubes, proving that our probe can clearly label the structure and morphology of liver microvessels. This work is of great significance for the visualization of HS.

CdTe@CdS quantum dots for labeling and imaging macrophages in liver frozen sections below the freezing point.

CdTe@CdS core-shell quantum dots with different particle sizes are synthesized by an aqueous method, and coating them with a CdS shell layer improves the quantum yield (36% → 59%) and fluorescence stability (37% → 77%) of CdTe@CdS quantum dots. When the KCl concentration (mass fraction) in the system is 15%, the CdTe@CdS quantum dot dispersion system remains in the liquid state at -20 °C, and the low temperature increases the fluorescence intensity. A QD-Ab probe is obtained after CdTe@CdS quantum dots are coupled with IgG; the circular dichroism shows that the IgG protein structure is not destroyed, while capillary electrophoresis, agarose gel electrophoresis and flow cytometry verify the conjugation efficiency. With rabbit anti-mouse EMR1 antibody as the primary antibody and QD-Ab as the secondary antibody, the hepatic macrophages in liver frozen sections are fluorescently labeled at -20 °C, and it is found that they are radially distributed in hepatic sinusoids with specific and highly efficient labeling; these results are verified by H&E staining and TEM. This technology can provide important technical support for in-depth understanding of the distribution of liver immune cells in the liver, and it can further provide a scientific basis to understand the relationship between the liver structure and function and pathological changes.

Adjuvant effect of two polysaccharides from the petals of Crocus sativus and its mechanisms.

Two polysaccharides from Crocus sativus petals (PCSPs), PCSPA and PCSPB, presented immunopotentiatory activity through activating macrophages via MAPK and NF-κB pathway. In this study, two PCSPs were investigated for the adjuvant effects and underlying mechanisms using ovalbumin (OVA) in mice. PCSPA and PCSPB remarkably not only boosted the OVA-specific IgG antibody and its isotype titers, but strengthened splenocyte proliferation and natural killer cell activities in immunized mice. Both PCSPs also dramatically triggered the production of Th1- and Th2-cytokines and facilitated the gene expression of Th1- and Th2-cytokines and transcription factors in OVA-stimulated splenocytes. In mechanisms, two PCSPs rapidly elicited the gene and protein expression of cytokines and chemokines, promoted the recruitment and antigen uptake of immune cells in the injected-muscles, and augmented the migration and antigen transport of immune cells to the draining lymph nodes. These findings demonstrated that PCSPs enhanced and improved immune responses and simultaneously elicited Th1- and Th2-immune responses to OVA through activating innate immune microenvironment, and that they could act as promising vaccine adjuvant candidates.

Caspase-1-Dependent Pyroptosis Mediates Adjuvant Activity of Platycodin D as an Adjuvant for Intramuscular Vaccines.

Platycodin D (PD) is a potent adjuvant with dual Th1 and Th2 potentiating activity, but its mechanisms of action remain unclear. Here, the C2C12 myoblast cell line and mice were used as in vitro and in vivo models to identify potential signaling pathways involved in the adjuvant activity of PD. PD induced a transient cytotoxicity and inflammatory response in the C2C12 cells and in mouse quadricep muscles. A comparative analysis of microarray data revealed that PD induced similar gene expression profiles in the C2C12 cells and in the quadricep muscles, and triggered rapid regulation of death, immune, and inflammation-related genes, both in vivo and in vitro. It was further demonstrated that caspase-1-dependent pyroptosis was involved in the PD-induced cytotoxicity and inflammatory response in the C2C12 cells via the Ca2+-c-jun N-terminal kinase (JNK)/p38 mitogen-activated protein kinase (MAPK)-NLR family pyrin domain containing 3 (NLRP3) inflammasome signaling pathway. Consistently, the in vivo analysis revealed that a local blockage of NLRP3 and caspase-1 inhibited PD-induced cytokine production and immune cell recruitment at the injection site, and impaired the adjuvant activity of PD on antigen-specific immune responses to model antigen ovalbumin (OVA) in mice. These findings identified the caspase-1-dependent adjuvanticity of PD and expanded the current knowledge on the mechanisms of action of saponin-based adjuvants.

A Perspective on Re-Detectable Positive SARS-CoV-2 Nucleic Acid Results in Recovered COVID-19 Patients.

OBJECTIVES: There have been reports on re-detectable positive nucleic acid tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in recovered coronavirus disease (COVID-19) patients. In this study, we look at the clinical characteristics, possible causes, pathogenesis, and infectivity of re-detectable positive patients and provide up-to-date information to public health policy planners and clinicians. METHODS: By consulting the latest research data and related progress data of re-detectable positive patients, this study addresses the implications that this special group brings to clinical work and disease prevention and control. RESULTS: We discuss in detail the phenomenon of re-detectable positive nucleic acid tests for recovered patients. There are many possible causes of a re-detectable positive, but there is no 1 factor that can fully explain this phenomenon. CONCLUSIONS: It can't be completely ruled out that the re-detectable positive patients are infectious. We should be alert to these re-detectable positive patients becoming chronic virus carriers, and virus serological IgM and IgG antibody tests should be added before patient discharge. It is urgent to find a more powerful evidence-based and virological basis for the integrity of viral ribonucleic acid and the variation of viral virulence with time through cell experiments in vitro and animal experiments in vivo.

[Cistanches tubulosa water extract protects the testis against cyclophosphamide-induced injury: Effect and mechanism].

OBJECTIVE: To investigate the protective effect of Cistanche tubulosa water extract (CTWE) against cyclophosphamide (CTX)-induced testis injury (TI) in mice and its action mechanism. METHODS: Thirty male mice were equally randomized into a normal control, a CTX-induced TI model control and a CTWE treatment group. After 7 days of adaptive feeding, the mice in the CTWE treatment group were treated intragastrically with CTWE at 10 g/kg/d, those in the normal control and TI model control groups with the same volume of normal saline qd all for 35 successive days, and those in the TI model control and CTWE treatment groups by intraperitoneal injection of cyclophosphamide at 80 mg/kg/d at 7, 14, 21, 28 and 35 days. Then all the animals were weighed, blood samples collected, and their testes and epididymides harvested for detection of the serum T content, examination of semen quality, measurement of testis weight, observation of histopathological changes in the testis, and determination of the levels of super oxide dismutase (SOD) and malondialdehyde (MDA) in the testis tissue and the mRNA expressions of the genes related to the nuclear factor erythroid-2-related factor (Nrf2) signaling pathway. RESULTS: The mice in the TI model control group, compared with the normal controls, showed significant decreases in the body weight (ï¼»34.13 ± 1.56ï¼½ vs ï¼»47.08 ± 1.98ï¼½ g, P < 0.05), testis weight (ï¼»81.82 ± 10.61ï¼½ vs ï¼»148.50 ± 14.82ï¼½ mg, P < 0.05), sperm concentration (ï¼»32.60 ± 5.29ï¼½ vs ï¼»78.90 ± 7.95ï¼½ ×106/ml, P < 0.05), sperm motility (ï¼»45.20 ± 7.09ï¼½% vs ï¼»86.70 ± 5.64ï¼½%, P < 0.05), serum T content (ï¼»7.49 ± 1.03ï¼½ vs ï¼»15.93 ± 1.36ï¼½ ng/L, P < 0.05), and SOD level (ï¼»152.22 ± 10.66ï¼½ vs ï¼»356.10 ± 30.95ï¼½ U/mg prot, P < 0.05), but remarkable increases in the percentage of morphologically abnormal sperm (MAS) (ï¼»39.30 ± 7.36ï¼½% vs ï¼»14.40 ± 3.53ï¼½ %, P < 0.05) and MDA level (ï¼»54.91 ± 5.12ï¼½ vs ï¼»31.71 ± 3.57ï¼½ nmol/mg prot, P < 0.05). The animals treated with CTWE, in comparison with the TI model controls, exhibited markedly increased body weight (ï¼»40.67 ± 2.13ï¼½ vs ï¼»34.13 ± 1.56ï¼½ g, P<0.05), testis weight (ï¼»121.21 ± 17.38ï¼½ vs ï¼»81.82 ± 10.61ï¼½ mg, P<0.05), sperm concentration (ï¼»58.40 ± 9.94ï¼½ vs ï¼»32.60 ± 5.29ï¼½ ×106/ml, P < 0.05), sperm motility (ï¼»72.30 ± 7.51ï¼½ % vs ï¼»45.20 ± 7.09ï¼½ %, P < 0.05), serum T content (ï¼»10.89 ± 1.07ï¼½ vs ï¼»7.49 ± 1.03ï¼½ ng/L, P < 0.05) and SOD level (ï¼»217.69 ± 24.59ï¼½ vs ï¼»152.22 ± 10.66ï¼½ U/mg prot, P < 0.05), but decreased percentage of MAS (ï¼»22.20 ± 6.07ï¼½% vs ï¼»39.30 ± 7.36ï¼½%, P < 0.05) and MDA level (ï¼»36.41 ± 4.27ï¼½ vs ï¼»54.91 ± 5.12ï¼½ nmol/mg prot, P < 0.05). The mRNA expressions of Nrf2, HO-1 and NQO-1 in the testis tissue were significantly down-regulated in the TI model controls compared with those in the normal controls (P < 0.05), and remarkably up-regulated in the CTWE treatment group in comparison with those in the TI model group (P < 0.05), while that of Caspase3 markedly increased in the TI model controls (P< 0.05) and decreased in the CTWE treatment group (P < 0.05). Histopathologically, the testis tissue of the TI model controls showed indistinct outlines from the base of the seminiferous tubule to the lumen surface, with disarranged and reduced layers of spermatogenic cells and decreased number of sperm in the seminiferous tubules, while the structure of the spermatogenic tubules recovered almost to normal in the CTWE treatment group. CONCLUSION: Cistanches tubulosa water extract can effectively inhibit cyclophosphamide-induced testis injury by enhancing the activity of antioxidant enzyme and regulating the expressions of the Nrf2 signaling pathway-related genes.