Exogenous nitric oxide stimulates early egress of Eimeria tenella sporozoites from primary chicken kidney cells in vitro

Egress plays a vital role in the life cycle of apicomplexan parasites including Eimeria tenella, which has been attracting attention from various research groups. Many recent studies have focused on early egress induced by immune molecules to develop a new method of apicomplexan parasite elimination. In this study, we investigated whether nitric oxide (NO), an immune molecule produced by different types of cells in response to cytokine stimulation, could induce early egress of eimerian sporozoites in vitro. Eimeria tenella sporozoites were extracted and cultured in primary chicken kidney cells. The number of sporozoites egressed from infected cells was analyzed by flow cytometry after treatment with NO released by sodium nitroferricyanide (II) dihydrate. The results showed that exogenous NO stimulated the rapid egress of E. tenella sporozoites from primary chicken kidney cells before replication of the parasite. We also found that egress was dependent on intra-parasitic calcium ion (Ca2+) levels and no damage occurred to host cells after egress. The virulence of egressed sporozoites was significantly lower than that of fresh sporozoites. The results of this study contribute to a novel field examining the interactions between apicomplexan parasites and their host cells, as well as that of the clearance of intracellular pathogens by the host immune system

Bis[(1S,1′S)-1,1′-(4-amino-4H-1,2,4-triazole-3,5-di­yl)diethanol-κN 1]bis­(nitrato-κO)zinc

In the title homochiral mononuclear compound, [Zn(NO3)2(C6H12N4O2)2], the ZnII atom is located on a twofold rotation axis and coordinated by two N atoms from two ligands and two O atoms from two NO3 − anions, adopting a distorted tetra­hedral coordination geometry. The compound is enanti­omerically pure and corresponds to the S diastereoisomer, with the optical activity originating from the chiral ligand. In the crystal, mol­ecules are connected into three-dimensional supra­molecular networks through O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds

Increased Neutralizing Antibody Production and Interferon-γ Secretion in Response to Porcine Reproductive and Respiratory Syndrome Virus Immunization in Genetically Modified Pigs

T cell-mediated immunity plays a prominent role in combating pathogens infection. Both the engagement of the T cell receptor with the peptide-bound major histocompatibility complex and a costimulatory signal are needed for the complete activation of the T cell. To determine whether host immune responses to vaccination could be improved by enhancing CD28-mediated costimulation and verify whether the boosted immune responses could protect the host against viral challenge, we produced a transgenic pig line expressing an extra copy of the CD28 gene controlled by its own promoter at the Rosa26 locus. As expected, in response to porcine reproductive and respiratory syndrome virus (PRRSV) strain vaccination, CD4+ T cells was remarkably increased in CD28 transgenic pigs and a similar response in CD8+ T cells was elicited after challenge. Importantly, because of increased T cell frequencies, the virus-neutralizing antibody against JXA-1 (a highly pathogenic Chinese PRRSV strain), as well as interferon-γ secretion, were enhanced in transgenic pigs. These findings in our translational study provide a novel concept for farm animal breeding in disease resistance, in which we may use the transgenic technology to force overexpression of confirmed immunity-promoting molecules like CD28 and produce an animal with enhanced immune responses to vaccination and broad-spectrum resistance to infectious diseases

Evaluation of Toxoplasma gondii as a live vaccine vector in susceptible and resistant hosts

<p>Abstract</p> <p>Background</p> <p><it>Toxoplasma gondii </it>has been shown to trigger strong cellular immune responses to heterologous antigens expressed by the parasite in the inbred mouse model <abbrgrp><abbr bid="B1">1</abbr></abbrgrp>. We studied the immune response induced by <it>T. gondii </it>as an effective vaccine vector in chickens and rabbits.</p> <p>Results</p> <p><it>T. gondii </it>RH strain was engineered to express the yellow fluorescent protein (YFP) in the cytoplasm. A subcutaneous injection of the transgenic <it>T. gondii </it>YFP in chickens afforded partial protection against the infection of transgenic <it>E. tenella </it>YFP. <it>T. gondii </it>YFP induced low levels of antibodies to YFP in chickens, suggesting that YFP specific cellular immune response was probably responsible for the protective immunity against <it>E. tenella </it>YFP infection. The measurement of T-cell response and IFN-γ production further confirmed that YFP specific Th1 mediated immune response was induced by <it>T. gondii </it>YFP in immunized chickens. The transgenic <it>T. gondii </it>stimulated significantly higher YFP specific IgG titers in rabbits than in chickens, suggesting greater immunogenicity in a <it>T. gondii </it>susceptible species than in a resistant species. Priming with <it>T. gondii </it>YFP and boosting with the recombinant YFP can induce a strong anti-YFP antibody response in both animal species.</p> <p>Conclusions</p> <p>Our findings suggest that <it>T. gondii </it>can be used as an effective vaccine vector and future research should focus on exploring avirulent no cyst-forming strains of <it>T. gondii </it>as a live vaccine vector in animals.</p

DNA vaccination with a gene encoding Toxoplasma gondii GRA6 induces partial protection against toxoplasmosis in BALB/c mice

<p>Abstract</p> <p>Background</p> <p>Infection with the protozoan <it>Toxoplasma gondii </it>causes serious public health problems and is of great economic importance worldwide. Protection from acute toxoplasmosis is known to be mediated by CD8+ T cells, but the <it>T. gondii </it>antigens and host genes required for eliciting protective immunity have been poorly defined. The <it>T. gondii </it>dense granule protein 6 (GRA6), recently proved to be highly immunogenic and produces fully immune protection in <it>T. gondii </it>infected BALB/c mice with an H-2L^dgene. The CD8+ T cell response of H-2L^dmice infected by the <it>T. gondii </it>strain seemed to target entirely to a single GRA6 peptide HF10-H-2L^dcomplex.</p> <p>Results</p> <p>To determine whether a GRA6-based DNA vaccine can elicit protective immune responses to <it>T. gondii </it>in BALB/c mice, we constructed a eukaryotic expression vector pcDNA3.1-HisGRA6 and tested its immunogenicity in a mouse model. BALB/c mice were vaccinated intramuscularly with three doses of GRA6 DNA and then challenged with a lethal dose of <it>T. gondii </it>RH strain tachyzoites. All immunized mice developed high levels of serum anti-GRA6 IgG antibodies, and <it>in vitro </it>splenocyte proliferation was strongly enhanced in mice adjuvanted with levamisole (LMS). Immunization with pcDNA3.1-HisGRA6 with LMS resulted in 53.3% survival of challenged BALB/c mice as compared to 40% survival of BALB/c without LMS. Additionally, immunized Kunming mice without an allele of H-2L^dfailed to survive.</p> <p>Conclusions</p> <p>Our result supports the concept that the acquired immune response is MHC restricted. This study has a major implication for vaccine designs using a single antigen in a population with diverse MHC class I alleles.</p

Transcriptome profile of halofuginone resistant and sensitive strains of Eimeria tenella

The antiparasitic drug halofuginone is important for controlling apicomplexan parasites. However, the occurrence of halofuginone resistance is a major obstacle for it to the treatment of apicomplexan parasites. Current studies have identified the molecular marker and drug resistance mechanisms of halofuginone in Plasmodium falciparum. In this study, we tried to use transcriptomic data to explore resistance mechanisms of halofuginone in apicomplexan parasites of the genus Eimeria (Apicomplexa: Eimeriidae). After halofuginone treatment of E. tenella parasites, transcriptome analysis was performed using samples derived from both resistant and sensitive strains. In the sensitive group, DEGs associated with enzymes were significantly downregulated, whereas the DNA damaging process was upregulated after halofuginone treatment, revealing the mechanism of halofuginone-induced parasite death. In addition, 1,325 differentially expressed genes (DEGs) were detected between halofuginone resistant and sensitive strains, and the DEGs related to translation were significantly downregulated after halofuginone induction. Overall, our results provide a gene expression profile for further studies on the mechanism of halofuginone resistance in E. tenella

Metabolomic Profiling of Mice Serum during Toxoplasmosis Progression Using Liquid Chromatography-Mass Spectrometry

Better understanding of the molecular changes associated with disease is essential for identifying new routes to improved therapeutics and diagnostic tests. The aim of this study was to investigate the dynamic changes in the metabolic profile of mouse sera during T. gondii infection. We carried out untargeted metabolomic analysis of sera collected from female BALB/c mice experimentally infected with the T. gondii Pru strain (Genotype II). Serum samples were collected at 7, 14 and 21 day post infection (DPI) from infected and control mice and were subjected to liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS)-based global metabolomics analysis. Multivariate statistical analysis identified 79 differentially expressed metabolites in ESI+ mode and 74 in ESI-mode in sera of T. gondii-infected mice compared to the control mice. Further principal component analysis (PCA) and partial least squares-discrimination analysis (PLS-DA) identified 19 dysregulated metabolites (5 in ESI+ mode and 14 in ESI-mode) related to the metabolism of amino acids and energy metabolism. The potential utility of these metabolites as diagnostic biomarkers was validated through receiver operating characteristic (ROC) curve analysis. These findings provide putative metabolite biomarkers for future study and allow for hypothesis generation about the pathophysiology of toxoplasmosis