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Salmonella is an important zoonosis.China is the largest pork consumer.Contaminated pork is the main source of Salmonella disease at home and abroad.There are many swine Salmonella vaccine in use in Europe.Now the current swine Salmonella vaccine is a live attenuated vaccine,Salmonella can reduce colonization in pigs,and can induce immune response efficiently after the two immunizations.The control effect is poor,at this stage of swine vaccine cross protection research,type of Salmonella and vaccine antigen are not the same.This paper reviews the research progress of swine Salmonella vaccine.
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Salmonella Derby is recognized as a major human food-borne pathogen causing food poisoning,septicaemia and other symptoms.Meanwhile,it can represent a severe threat to livestock breeding and health.The objective of this review is to summarize novel research progress on epidemic,genomics,pathogenic mechanism of Salmonella Derby for provide reference to related research.
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Salmonella enterica serovar Choleraesuis strain C500 is a live attenuated vaccine that has been widely used in Chi‐na for over 50 years to prevent piglet paratyphoid .However ,as C500 is obtained by chemical methods ,the genetic background of this strain remained unclear .In this study ,we compared the genomic differences between the virulent reference strain C 78‐2 and C500 by suppression subtractive hybridization combined with the mirror orientation selection method (MOS‐SSH ) .Six genes (asr ,ydgF ,ydgD ,ydgE ,rpoS ,and ptsG) were lost in C500 strain .Using real‐time PCR analysis ,we demonstrated that the genes regulated by rpoS ,a vital transcriptional regulator playing an important role in Salmonella infection ,were downregulated in C500 .Additionally ,the virulence of the rpoS mutant strain C78‐2ΔrpoS was 100 000 times lower than the parental strain in BALB/c mice .So loss of rpoS gene is the major factor leading to the attenuation of C500 strain .
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Tuberculosis (TB) is an infectious disease endangering people’s health around the world ,and diagnosis and ra‐tional treatment are the key to control TB .However ,currently there is no diagnostic golden standard for latent tuberculosis in‐fection (LTBI) .The tuberculin skin test and IFN‐gamma release analysis are regarded as effective methods for TB diagnosis , which is based on host’s cellular immune response to mycobacterial antigens .But the two methods are not perfect ;neither test can make a clear distinction between latent infection and active TB .Flow Cytometry (FCM ) has been widely used in the field of clinical medicine .In recent years ,substantial advances have been achieved in the fields of TB diagnosis and evaluation of treat‐ment efficacy by using the FCM intracellular cytokine detection technology .In this paper ,we will review the latest progress in tuberculosis diagnosis research by using flow cytometry in recent years .
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Salmonella is a pathogenic bacteria to human and animals ,which can cause seriously complication and death . Salmonella pathogenicity is from the reactions of SP‐1 and SP‐2 T3SS effector proteins .In this paper ,the functions of different T3ss effector proteins in different infection periods is reviewed to provide a reference for further understanding the pathogenesis mechanisms of Salmonella .
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The prevalence of human and animal listeriosis for nearly 11 years in China was investigated in this study . The literature information about listeriosis in China from 2002 to 2012 was collected through retrieval system to make clinical and epidemiological statistical analysis of listeriosis .Cases of listeriosis were reported in 27 (79% ) provinces of China .The re-sult showed that animal listeriosis was reported for 123 times ,among these reports ,most were from pigs (39% ) ,and the sheep was in second place .Central nervous system infection was the main clinical manifestation of listeriosis in animals (72% ) . For human listeriosis ,84 clinical cases of listeriosis were reported ,including 35% cases in non-perinatal stage and 65% cases in perinatal stage .The main clinical manifestation of listeriosis was septicemia (51% ) .According to the result of investigation about listeriosis based on literatures information ,Listeriamonocytogenes caused humans and animals listeriosis annually ,which were reported in most provinces of China .The epidemic characteristics for listeriosis suggested that it was essential to strength-en the prevention and control of listeriosis .
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Proteins encoded by regions of difference (RD) of Mycobacterium tuberculosis (MTB) constitute a potential source of specific antigens for vaccine development and immunodiagnosis .In the present study ,four genes named nrdF1 , pe_pgrs35 ,rv1985c ,and rv1986 from RD2 of MTB were cloned and overexpressed in E .coli with the induction of IPTG .Western blotting assay showed that these recombinant fusion proteins could well react with anti-His tag monoclonal antibody ,which in-dicated their good immunoreactivity .The serodiagnosis potential applications of these four proteins in bovine tuberculosis were further evaluated .An indirect ELISA assay was established by using fusion proteins as coating antigens for detection of their specific antibodies in bovine sera .The positive rates were 7 .35% in NrdF1 ,22 .06% in PE_PGRS35 ,16 .18% in Rv1985c and 16 .18% in Rv1986 respectively .All the results suggest that these fusion proteins have the potential application in serodiagnosis of bovine tuberculosis .
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Listeriamonocytogenes is a facultative intracellular bacterium that enters professional antigen presenting cells , presents passenger antigens to the major histocompatibility complex class I and II pathways ,then elicits CD+4 and CD+8 T-cell-mediated immune responses .It was demonstrated that attenuated Listeriamonocytogenes as a novel live vaccine vector in deliv-ering tumor antigens of cervical cancer and melanoma etc .,could induce strong protective immune response ,and shows effec-tive antitumor immunotherapeutics .This review discussed the characteristics of immune responses elicited by Listeria monocy-togenes ,and the progress of its antitumor immunotherapeutics as delivery vaccine vector .
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Bovine interferon-gamma (BoIFN-gamma) gene was amplified by reverse transcription polymerase chain reaction (RT-PCR) from total RNA of bovine spleen lymphocytes stimulated with ConA. The products of RT-PCR were cloned into pVAX1 vector, positive recombinant clone was identified by restriction enzyme digestion and sequencing. The recombinant plasmid pVAX1-BolFN-gamma was transfected into COS-7 cells mediated by lipofectine, indirect immunofluorescent assay analysis confirmed that rBoIFN-gamma was expressed in COS-7 cells. BoIFN-gamma gene (without signal peptide) was cloned into pET-30a(+) and pGEX-6p-1 vector, and transformed into the Escherichia coli cells. After optimizing the induction condition, SDS-PAGE analysis showed that the expression products were all found in soluble form and had a molecular weight of 23 kDa and 43 kDa respectively. BoLFN-gamma precursor gene (with signal peptide) was cloned into transfer vector pFastBac 1, and transformated into DH10Bac E. coli cells. By site-specific transposition, BoIFN-gamma gene was integrated into shuttle vector Bacmid, and transfected into the Sf9 insect cells mediated by lipofectine to produce recombinant baculovirus. Indirect immunofluorescent assay analysis confirmed that rBac-BoLFN-gamma was expressed successfully in Baculovirus vector system. The antiviral activities of rHis-BoIFN-gamma, rGST-BoIFN-gamma and rBac-BoIFN-gamma were up to 8.389 x10(7) U/mg, 6.554 x10(5) U/mg and 4.096 x 10(4) U/mL respectively, which were analyzed in MDBK/VSV system. A sandwich ELISA was established using monoclonal antibodies 3E6 and 5G4, which can detect BoIFN-gamma in quantity and provide a useful method for the clinical practice and research of BolFN-gamma.
Subject(s)
Animals , Cattle , Antiviral Agents , Pharmacology , Baculoviridae , Genetics , Metabolism , COS Cells , Chlorocebus aethiops , Escherichia coli , Genetics , Metabolism , Genetic Vectors , Genetics , Interferon-gamma , Genetics , Pharmacology , Recombinant Proteins , Genetics , Pharmacology , TransfectionABSTRACT
Quinolones are broad-spectrum antibacterial agents used in human and veterinary medicine, and their extensive use have been associated with a rise of the quinolone resistance. In the present study, the quinolone resistance of avian E.coli and Salmonella isolates was evaluated and compared, in which 344 avian E.coli and 224 Salmonella isolates from 1990s were serogrouped with antisera and thc antimicrobial susceptibility test to 10 quinolones was carried out by using the Kirby-Bauer method recommended by Clinical and Laboratory Standards Institute (CLSI). It was demonstrated that the 344 isolates of avian E.coli distributed in 27 serogroups and 68.90% (237/344) of the isolates belonged to four O-serogroups: i.e. O1, O2, O18, O78, and the 224 isolates of avian Salmonella were all determined to be Salmonella pullorum. The drug-resistance rate of avian E. coli isolates to nalicixic acid from 1993-1999 was more than 60%(64.43%,131/181), whereas those of isolates to 9 antibiotics from 2000-2008 had a drug-resistance rates of more than 60%, namely,nalicixic acid(92.02%), fleroxacin(79.75%), pipemidic acid(79.14%), enrofloxacin(78.53%), enoxacin(76.07%), lomenfloxacin(74.85%), ciprofloxacin(69.33%), norfloxacin(63.80%) and ofloxacin(61.35%). For the 4 O-serogroups of the avian E.coli isolates, the drug-resistance rates of more than 50% to antimicrobials were as follows: O78 isolates to 7 antimicrobials;O18 isolates to 5 antimicrobials, and O1 and O2 isolates just to 3 antimicrobials. The quinolone resistance of Salmonella isolates was much lower than E.coli, in which 101 salmonella isolates from 1993-1999 were all susceptible to quinolones. Nalicixic acid resistance of salmonella isolate firstly appeared in 2000, and the drug-resistance rate of salmonella isolates from 2000-2008 was found to be more than 60% for nalicixic acid(83.74%), but those to other quinolones were comparatively lower. These results indicated that the quinolone resistance of avian E.coli and salmonella were increasing in the past two decads because of the over-use of antibiotics.
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Objective To determine the immune responses induced by recombinant Salmonella ty-phimurium expressing the secreting antigen ESAT-6 of Mycobacterium tuberculosis. Methods ESAT-6 cod-ing gene was cloned and identified by PCR and sequencing. Prokaryotic expression plasmid pYA33-esat car-rying the ESAT-6 coding sequence was constructed firstly and electro-transformed into an attenuated strain X4550 of Salmonella typhimurium, the recombinant bacteria was named as X4550(33-esat). C57BL/6 mice were immunized intranasally (I. N) with 108 CFU recombinant bacteria at day 0 and 18. Cells from spleen, lung, mesenteric lymph node (MLN) and Peyer's patch (PP) were collected from mice after second immu-nization, and the specific IFN-γ-secreting cells and IL-4-secreting cells were detected by ELISPOT assay u-sing ESAT-6 peptide as stimulus. Furthermore, CTL effects were in vivo evaluated by CFSE assay. Results The results showed that cellular immune responses specific for ESAT-6 could be detected by ELISPOT assay. In lung and PP cells, immune responses against ESAT-6 were biased toward Th1 type, the frequency of IFN-γ-secreting cells was much higher than that of IL-4-secreting cells. In splenocytes and MLN cells, the anti-gen specific immune responses acted as Thl and Th2 balance, the frequency of IFN-γ-secreting cells was close to that of IL-4-secreting cells. CFSE assay indicated that recombinant bacteria could induce the high level of CTL effects specific for ESAT-6 peptide. Conclusion These results suggested that recombinant Sal-monella typhimurium X4550(33-esat) not only can induce cellular immune responses, but also can elicit specific CTL responses after I. N immunization. It also provided the useful information for the control of infec-tious disease of tuberculosis.
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Objective:To analyze the efficiency of delivery for CD8+ T cell epitope by attenuated E.coli vector.Methods:The recombinant E.coli strain 13A(pG2F),harbouring the eukaryotic expression plasmid pG2F with CD8+ T cell epitope of Ovalbumin (OVA) and green fluorescent protein (GFP) marker at the C-terminal was used to infect into LKb cells,bone marrow dendritic cells (BMDC).The efficiency of presentation for CD8+T cell epitope delivered by recombinant bacteria was analyzed by in vitro antigen presentation assay.C57BL/6 mice were immunized intravenously with 13A(pG2F).Murine IFN-? secreting cells were detected in murine splenocytes by enzyme-linked immunospot assay (ELISPOT).Results:After the infection of LKb cells,BMDC by recombinant bacteria,about 0.3%～4% of cells were GFP positive.The results indicated that attenuated strain 13A could deliver the eukaryotic expression plasmid into mammalian cells.At 2 h post infection,CD8+ T cell epitope was presented on the surface of those LKb,BMDC cells infected by 13A (pG2F) could be recognized by B3Z T hybridoma cells.The presentation efficiency of LKb cells for OVA CD8+ T cell epitope was increased at 48h after infection.Furthermore,the presentation efficiency of BMDC was higher than those of LKb cells under the same condition.The recombinant bacteria 13A(pG2F) could induce cellular immune responses in C57BL/6 mice.Conclusion:Attenuated E.coli can effectively deliver the CD8+ T cell epitope in vitro and in vivo.