Showing papers in "Comparative Immunology Microbiology and Infectious Diseases in 2005"
TL;DR: A positive impact of the probiotic on cellular immune responses of infected broilers as compared to control chickens resulting in enhanced resistance to EA as shown in reduced fecal oocyst shedding.
Abstract: Previously we have shown that resistance to Eimeria acervulina (EA) infection in broiler chickens was enhanced by a probiotic treatment. In the present studies, we examined cytokine and oocyst production under similar conditions using a commercial Lactobacillus- based probiotic. Day-old male broiler chicks were fed control or probiotic diets and were orally challenged with either 2×10 4 (Experiment 1) or 1×10 4 (Experiment 2) oocysts of EA at 3 weeks of age. For the first experiment, fecal oocyst shedding and IFN-γ levels in the culture supernatants of ConA-stimulated spleen lymphocytes were evaluated. Humoral and local cell-mediated immunity in the second experiment were assessed by evaluating antibody and cytokine (IFN-γ and IL-2) levels in sera and intestinal secretions on a 3-day interval post inoculation. Results showed small but significant ( P Lactobacillus- based probiotics in food animals.
110 citations
TL;DR: Study showed that PPR virulent virus causes marked immunosuppression as evidenced by leukopenia, lymph Openia, and reduced early antibody response to both specific and nonspecific antigen.
Abstract: Effect of virulent and attenuated peste des petits ruminants (PPR) virus on the immune response to nonspecific antigen (ovalbumin) was investigated. Clinical and serological responses were monitored in goats administered with ovalbumin concurrently with either PPR vaccine or virulent virus. Study showed that PPR virulent virus causes marked immunosuppression as evidenced by leukopenia, lymphopenia, and reduced early antibody response to both specific and nonspecific antigen. These observations were predominant particularly during acute phase of disease (4-10 days post-infection). On the other hand, the vaccine virus induced only a transient lymphopenia without significantly affecting the immune response to nonspecific antigen or to itself during this period. Further, the antibody levels to ovalbumin in the group administered with virulent PPRV increased significantly between days 28 and 35 post-infection in comparison to the titers in other two groups given with either ovalbumin alone or in combination with vaccine.
101 citations
TL;DR: It is suggested that IBDV-induced apoptosis is a multistep process involving virus replication, protein expression, and release of virions.
Abstract: The ability of infectious bursal disease virus (IBDV) serotypes 1 and 2, and the role of VP4 of both serotypes as well as the capacity of three IBDV intermediate serotype 1-specific vaccine strains to induce apoptosis in a chicken B-lymphocyte cell line, DT40, were investigated using the TUNEL technique It was observed that IBDV serotype 1 infected the DT40 cell line and directly induced apoptosis In contrast, the non-pathogenic serotype 2 neither infected nor induced apoptosis, but was able to reduce the serotype 1-induced apoptosis when the two viruses were present in combination VP4 of both serotypes did not induce apoptosis IBDV VP2 of serotype 2 induced apoptosis in the same proportion and intensity as VP2 of serotype 1 IBDV intermediate vaccines varied in their ability to induce apoptosis in the DT40 cell line, which was also decreased-delayed in presence of serotype 2 IBDV We hypothesize that both serotypes compete for the same receptor in DT-40 cells, and suggest that IBDV-induced apoptosis is a multistep process involving virus replication, protein expression, and release of virions
54 citations
TL;DR: In this article, the authors investigated the prevalence of virulent Rhodococcus equi in clinical isolates from 41 foals (19 sporadic and seven endemic cases) in Brazil between 1991 and 2003.
Abstract: We investigated the prevalence of virulent Rhodococcus equi in clinical isolates from 41 foals (19 sporadic and seven endemic cases) in Brazil between 1991 and 2003 Of the 41 virulent isolates, six contained an 85-kb type I plasmid, 33 contained an 87-kb type I plasmid, both of which have been found in isolates from the Americas, and the remaining two contained a new variant, which did not display the Eco RI, Eco T22I and Bam HI digestion patterns of the 11 representative plasmids already reported (85-kb types I–IV; 87-kb types I and II; 90-kb types I–V) We tentatively designated the new variant as the ‘87-kb type III’ plasmid, because its Bam HI digestion pattern is similar to that of the 87-kb type I plasmid This is the first report of the molecular epidemiology surveillance of virulent R equi in clinical isolates from Brazilian foals
48 citations
TL;DR: Findings suggest that DCC from this region are not being colonized with commensal or potentially pathogenicEnteric bacteria from agricultural or human sources and that enteric bacteria isolated from these birds are unlikely to contribute to a gene pool of antimicrobial drug resistance.
Abstract: Cloacal and pharyngeal swabs from 100 tree-nesting Double-crested cormorant (DCC) chicks were examined by culture for commensal and potentially pathogenic bacteria. No Salmonella or Erysipelothrix were isolated from the cloacal swabs. Twenty-two cloacal swabs were positive for Campylobacter, of which 14 were C. jejuni, C. coli, and 1 C. lari. None belonged to common serotypes isolated from humans or animals in recent years in Canada. Tests for antimicrobial drug resistance among 187 commensal Escherichia coli isolates from the cloacal swabs indicated that ≤5% were resistant to any of the 12 antibiotics tested. This contrasts with the frequently high resistance rates among E. coli isolates from poultry. Pharyngeal swabs from DCC were negative for Pasteurella multocida. Culture of cloacal swabs from 100 ground-nesting DCC chicks resulted in the recovery of 19 Salmonella isolates, all of which were S. enterica serotype Typhimurium. None of these isolates were resistant to any of the 12 antibiotics tested. Altogether, these findings suggest that DCC from this region are not being colonized with commensal or potentially pathogenic enteric bacteria from agricultural or human sources and that enteric bacteria isolated from these birds are unlikely to contribute to a gene pool of antimicrobial drug resistance.
43 citations
TL;DR: Findings would suggest that type 1 fimbriae can play an important role in E. coli infection in breeders with salpingitis and attachment to oviduct epithelium from old birds was found to be superior to that observed using corresponding material from young birds.
Abstract: Thirty isolates of Escherichia coli from broiler breeders with salpingitis were studied. Using the slide agglutination test, the isolates were found to belong to serogroups O1, O2, O5, O36, O45, O53 and O78. Pathogenicity for day-old chicks was determined by air sac inoculation and isolates were categorized as having high, intermediate or low virulence. Growth on iron starvation medium was observed together with aerobactin production. Based on the results of in vitro adherence tests, attachment to oviduct epithelium from old birds was found to be superior to that observed using corresponding material from young birds. DNA hybridization testing for type 1, P, and S fimbriae revealed predominant expression of type 1, correlating with mannose-sensitive hemagglutination using guinea-pig erythrocytes. In this study, P and S fimbriae were not considered to be important adherence factors. Study findings would suggest that, as far as salpingitis is concerned, type 1 fimbriae can play an important role in E. coli infection in breeders. An interesting result to emerge from the study was the observation that E. coli isolates were completely resistant to serum from young breeders, whereas they were completely sensitive using serum from older breeders. Based on serogroups involved, pathogenicity for day-old chicks and virulence indicators, the salpingitis isolates were similar to those from cases of chronic respiratory disease.
37 citations
TL;DR: The everted sleeve method, devised for the in vitro study of intestinal absorption, was used in this study to investigate the uptake of Mycobacterium avium subsp.
Abstract: The main lesions of paratuberculosis in ruminants are in the small intestine. Previous studies have shown that the bacterium enters the small intestine through M cells found in the follicle-associated epithelium lining the domes of the Peyer's patches. The everted sleeve method, devised for the in vitro study of intestinal absorption, was used in this study to investigate the uptake of Mycobacterium avium subsp. paratuberculosis in goat intestine. Everted small intestinal sleeves of goat kids, prepared from areas with and without Peyer's patches, were incubated for 60 min in 3H-labeled bacterial solution. The results of this study imply that the bacteria can enter the intestinal mucosa of the jejunum, both in areas with and without Peyer's patches. These findings indicate, therefore, that M. avium subsp. paratuberculosis bacteria not only enter through M cells but also through enterocytes.
36 citations
TL;DR: Ehrlichial seropositivity was increased in blue-oak foothill pine, montane hardwood, and redwood vegetation regions, and decreased in coastal sagebrush and cropland, and increased exposure to B. burgdorferi occurred in blue oak woodland.
Abstract: Ixodes pacificus is the main tick vector for transmission of Anaplasma phagocytophilum and Borrelia burgdorferi to large vertebrates in California. The present study was undertaken in I. pacificus-infested counties in California to examine spatial and temporal relationships among A. phagocytophilum and B. burgdorferi-exposed coyotes with vegetation type and climate. The overall A. phagocytophilum and B. burgdorferi seroprevalences were 39.5% (N=215) and 18.9% (N=148), respectively, with no association with sex. PCR for A. phagocytophilum and B. burgdorferi was negative in all blood and kidney samples. Increased seroprevalence was a positive function of rainfall. Ehrlichial seropositivity was increased in blue-oak foothill pine, montane hardwood, and redwood vegetation regions, and decreased in coastal sagebrush and cropland. Increased exposure to B. burgdorferi occurred in blue oak woodland.
32 citations
TL;DR: It is suggested that the regression of tumor growth consequent to physical exercise training of tumor bearing host, may be due to an exercise-dependent augmentation of macrophage tumoricidal functions.
Abstract: We have reported that the ascitic growth of a transplantable T cell lymphoma of spontaneous origin, designated as Dalton's lymphoma (DL), is associated with a concomitant immunosuppression. We have also reported that progressive in vivo growth of DL resulted in an inhibition of macrophage functions. In present investigation we report that physical exercise by DL-bearing mice, on a treadmill on a daily basis for various time durations for 10 days, increased the life span along with an inhibition of tumor growth. A significant decrease in the volume of ascitic fluid and number of cells in the tumor was obtained in mice, which underwent exercise. DL cells obtained from exercised groups showed a decreased proliferation in vitro. An augmentation in the percent of cells showing apoptotic morphology and percent specific DNA fragmentation was observed, suggesting that physical exercise increased the incidence of apoptosis in tumor cells. Moreover, macrophages obtained from tumor-bearing mice, which underwent exercise training, showed an augmented tumoricidal activity and production of tumoricidal molecules like interleukin-1 (IL-1), tumor necrosis factor (TNF) and nitric oxide (NO). On the basis of this study it is suggested that the regression of tumor growth consequent to physical exercise training of tumor bearing host, may be due to an exercise-dependent augmentation of macrophage tumoricidal functions.
28 citations
TL;DR: In this article, 35 pregnant cows from a free-Brucellosis herd, previously vaccinated as calves with 1 x 10(10) CFU of RB51, were revaccinated with RB51 reduced dose, and then introduced into a herd with an active outbreak.
Abstract: It is a dogma, that RB51 vaccination does not induce antibodies that interfere with Brucellosis diagnosis, therefore any animal positive to serological test is considered as an infected animal. To determine protection against Brucellosis virulent field strain, 35 pregnant cows from a free-Brucellosis herd, previously vaccinated as calves with 1 x 10(10) CFU of RB51, were revaccinated with RB51 reduced dose, and then introduced into a herd with an active outbreak. Seventeen cows resulted positive in card test after revaccination. All 35 pregnant revaccinated cows had normal parturition; nevertheless, RB51 vaccine strain was isolated from milk and vaginal exudates from two cows after delivery at day 120 post-revaccination. At 150 days post-revaccination, two cows were positives to card and rivanol test and the field virulent strain was isolated. Revaccination with a reduced dose of RB51 in endemic zones did not cause abortion and protected 94% of animals against field infection, but caused an atypical response to conventional serological tests.
27 citations
TL;DR: This work analyzed T cell function among six captive tuatara by assessing concanavalin A (Con A), phytohemagglutinin (PHA) and mixed lymphocyte reaction (MLR) induced T cell proliferation.
Abstract: Tuatara are the sole survivors of an entire order of reptiles that thrived during the age of the dinosaurs. Therefore, knowledge of their physiology is critical to understanding the phylogeny of reptiles. Previous studies of the immune system of the tuatara did not assess T cell function. We analyzed T cell function among six captive tuatara by assessing concanavalin A (Con A), phytohemagglutinin (PHA) and mixed lymphocyte reaction (MLR) induced T cell proliferation. Peripheral blood mononuclear cells from six out of six and four out of four tuatara tested exhibited significant proliferative responses to Con A and PHA, respectively, as measured by an MTT reduction assay. A lower level of proliferation was detected in an MLR. However, Con A activated lymphocytes were not cytotoxic for a xenogeneic murine mastocytoma cell line (P815).
TL;DR: It is demonstrated that genes gI, gE and US9 of BHV-5 are important for its neuropathogenicity and its ability to reactive from latency.
Abstract: In this work, a role for the genes encoding glycoproteins I (gI) and E (gE) and the US9 protein of bovine herpesvirus type 5 (BHV-5) in neuropathogenicity and reactivation of latent infections was examined. Calves infected intranasally with a gI/gE/US9 deleted recombinant shed up to 10(2.85) TCID50/ml infectious virus in nasal secretions. Calves infected with the wild type BHV-5 parental virus shed up to 10(5) TCID50/ml virus. No signs of disease were observed in calves infected with the recombinant virus, whereas those infected with wild type virus displayed respiratory and neurological signs. The recombinant was only able to reach the basal portions of the central nervous system. In contrast, wild type virus was found widespread within the brain. Reactivation with dexamethasone 60 days post-infection resulted in reactivation of wild type virus, whereas the recombinant virus could not be reactivated. These studies demonstrate that genes gI, gE and US9 of BHV-5 are important for its neuropathogenicity and its ability to reactive from latency.
TL;DR: The ovine was used as bioreactor for the production and optimization of anti-tetanus toxin antibody and gave the highest yield of protein with specific activity and the purest Fab product.
Abstract: We used the ovine as bioreactor for the production and optimization of anti-tetanus toxin antibody Four female sheep were immunized with human tetanus vaccine (TT-alum) every two weeks for 16 weeks, after which serum was collected and its titer was estimated by ELISA The highest titer obtained was 39,000 IU ml-1 To optimize a purification protocol for ovine anti-tetanus toxin, we used four procedures; weak anion (DEAE-Sephadex), weak cation (CM-Sephadex), ammonium sulfate precipitation alone or in combination with caprylic acid Fifty percent saturation with ammonium sulfate combined with caprylic acid gave us the highest yield of protein with specific activity and the purest Fab product
TL;DR: In this article, the role of antioxidants as an adjunct to antibiotics in the treatment of infective process of uropathogenic E. coli is evaluated further, and the authors have shown that the severity of symptomatic infections and tissue damage during the infective processes depends upon the magnitude of the inflammatory response triggered by the uropathyogen which in turn is dependent upon the amount of extrcellular release of reactive oxygen species by the phagocytic cells.
Abstract: The human urinary tract is able to combat with the microbial invasion under normal circumstances. To cause urinary tract infection the organism has to evade the host defense mechanisms by possessing distinct properties which contribute to the virulence of the organism hence called virulence determinants Ninety percent of uncomplicated urinary tract infections are caused by Escherichia coli, hence the knowledge of the virulence determinants of this organism can be extrapolated to other uropathogenic organism as well. Virulence determinants of uropathogenic E. coli include adhesins, siderophore production, polysaccharide coating, hemolysin production, outer membrane proteins etc. The intestinal E. coli, which are the reservoir of E. coli for causing UTI, lack these virulence determinants. On the other hand these virulence determinants enable the organism to colonize and invade the urinary tract. In addition these are important in acquiring the nutrients in other wise nutrient deficient environment. Further, they also help the organisms in triggering an inflammatory response and hence bringing about pathological changes which leads to symptomatic UTI. Severity of symptomatic infections and tissue damage during the infective process depends upon the magnitude of the inflammatory response triggered by the uropathogen which in turn is dependent upon the amount of extrcellular release of reactive oxygen species by the phagocytic cells; hence role of antioxidants as an adjunct to antibiotics in the treatment of infective process needs to be evaluated further.
TL;DR: Results indicate that ICAN is an efficient, sensitive and simple system to detect invA of Salmonella species in developing countries such as Zambia.
Abstract: The isothermal and chimeric primer-initiated amplification of nucleic acids (ICAN) is a new isothermal DNA amplification method composed of exo Bca DNA polymerase, RNaseH and DNA-RNA chimeric primers. We detected invA of Salmonella from chicken carcasses, egg yolk and cattle fecal samples. Fifty-three of 59 isolates were invA-positive in ICAN-chromatostrip detection. The result was consistent with those obtained by standard PCR. Salmonella invA was detected in 12 of 14 carcass rinses by ICAN, while in 7 of 14 rinses by standard PCR. These results indicate that ICAN is an efficient, sensitive and simple system to detect invA of Salmonella species in developing countries such as Zambia.
TL;DR: The data suggest the potential use of this combined vaccine based on plasmids encoding the membrane-anchored or secreted forms of bovine herpesvirus type 1 glycoprotein B and D in in vivo trials of calves, in order to evaluate its protective efficacy.
Abstract: Although DNA vaccines have several advantages over conventional vaccines, antibody production and protection are often not adequate, particularly in single plasmid vaccine formulations. Here we assessed the potential for a combined vaccine based on plasmids encoding the membrane-anchored or secreted forms of bovine herpesvirus type 1 (BHV-1) glycoprotein B and D (gB and gD) to induce neutralizing and cell mediated immune responses in mice. Animals were injected by intramuscular, subcutaneous and intranasal routes. Mice immunized with the combined vaccine containing the secreted forms of BHV-1 glycoproteins developed higher titers of anti-BHV-1 neutralizing antibodies, compared to wild type gB/gD combined plasmids and to single plasmid injected groups. Cellular immunity was also developed in mice immunized with combined vaccines, whereas low or no response were observed in single plasmid injected animals. The data suggest the potential use of this combined vaccine in in vivo trials of calves, in order to evaluate its protective efficacy.
TL;DR: No statistically significant differences were found in the different stages of immune response between the rest and immediately after physical exercise to two breeds, however, the chemotaxis was significant higher at rest in the AA than SA breed.
Abstract: The aim of the present paper was: (1) to find out if there were any differences in the nonspecific immunological pattern of peripheral blood neutrophil between two breeds of horses (AA and SA); (2) to evaluate the effects of an exercise in the aerobic–anaerobic threshold. This has been observed in a group of 11 untrained horses (6 SA and 5 AA) of 2.5 years old. No statistically significant differences were found in the different stages of immune response between the rest and immediately after physical exercise to two breeds. However, the chemotaxis was significant higher at rest in the AA than SA breed. A positive correlation was found at rest between the phagocytic and oxidative metabolism activity for AA breed and a negative correlation too between the adherence and chemotaxis with phagocytic capacity, immediately after exercise test, for the same breed.
TL;DR: Macrophages of golden-mantled ground squirrels bind LPS at a wide range of temperatures throughout their annual cycle; an ability shared between hibernators and non-hibernators alike.
Abstract: This study evaluates binding of bacterial lipopolysaccharide (LPS) by splenic macrophages from golden-mantled ground squirrels (Spermophilus lateralis, GMGS), a hibernating mammal, at a variety of in vitro incubation temperatures to determine whether this aspect of immune function is effective at low body temperatures. LPS-binding by ground squirrel macrophages was compared to that of rat splenic macrophages. Macrophages were collected from squirrels at discreet stages in their annual cycle and incubated with fluorescein-labeled LPS (LPS-FITC). The percentage of GMGS that bound LPS-FITC did not change as a function of hibernation season or as a function of incubation temperature. The total amount of LPS-FITC bound per cell was similarly unaffected by season or temperature, however, macrophages from torpid squirrels bound more LPS-FITC than cells from normothermic squirrels. Macrophages of golden-mantled ground squirrels bind LPS at a wide range of temperatures throughout their annual cycle; an ability shared between hibernators and non-hibernators alike.
TL;DR: The efficiency of Listeria enrichment broth (LEB) for isolation was examined by the recovery of artificially inoculated L. monocytogenes in contents of swine cecum, and it was suggested that the marked rise of the L.monocyTogenes isolation was due to the spread of the organism among swine.
Abstract: The actual prevalence of Listeria monocytogenes from contents of swine cecum was investigated. The efficiency of Listeria enrichment broth (LEB) for isolation was examined by the recovery of artificially inoculated L. monocytogenes in contents of swine cecum. The numbers of organisms did not increase after 48 h incubation, but increased when the rapid decrease in pH of the LEB was adjusted. Between 1991 and 1993, 250 contents of swine cecum were examined for the prevalence of L. monocytogenes using LEB enrichment, either with or without pH adjustment. L. monocytogenes was isolated from 74 samples in 1993 with pH adjustment, however, no organisms were isolated in 1991 and 1992. It was suggested that the marked rise of the L. monocytogenes isolation was due to the spread of the organism among swine. Furthermore, 67 out of the 74 isolates were identified as 1/2c by serotyping. The serovar 1/2c strains showed genetic diversity by random amplified polymorphic DNA.
TL;DR: Results indicated that MV particle binding to and/or incorporation into cells stimulated IL-8 expression in A549 cells, a lower airway epithelial cell line, after MV inoculation.
Abstract: Measles virus (MV) infection primarily targets epithelial cells of the respiratory tract, which have the potential to synthesize a variety of cytokines. In this report, we studied the effect of MV infection on the production of interleukin (IL)-8 by the pulmonary epithelial cells. A549 cells, a lower airway epithelial cell line, produced IL-8 after MV inoculation in a dose- and time-dependent manner. The IL-8 production was little affected by UV-inactivation of MV and scarcely suppressed by cycloheximide treatment. These results indicated that MV particle binding to and/or incorporation into cells stimulated IL-8 expression in A549 cells.
TL;DR: Results indicate that the rSwIL-4 is biologically active in both in vitro and in vivo treatments, and Depending on the administration time, pro-inflammatory cytokine productions by IL-4 can cause either inhibitory or stimulatory regulation.
Abstract: The in vitro effect and the in vivo influence of recombinant swine IL-4 (rSwIL-4) were characterized in various swine cells and in nursery pigs on LPS-induced endotoxic shock and pro-inflammatory cytokine productions. In in vitro experiment, the rSwIL-4 induced a proliferation of CD4 positive T cells in mitogen-prestimulated peripheral blood mononuclear cell (PBMC). In addition, the rSwIL-4, which was produced from insect cells, promoted the differentiation of monocytes into immature dendritic cells in combination with granulocyte macrophage-colony stimulating factor (GM-CSF). Furthermore, the rSwIL-4 successfully suppressed the LPS-induced secretion of TNF-α, IL-1α, IL-6, IL-8, and IL-18 from swine alveolar macrophages when rSwIL-4 was treated at the same time with LPS. In in vivo experiment in nursery pigs, subcutaneous pretreatment of rSwIL-4, which was produced from baculovirus expression system, enhanced the severity of respiratory failure with endotoxic shock, and increased the production of TNF-α and IL-18 in response to inoculation with LPS. These results indicate that the rSwIL-4 is biologically active in both in vitro and in vivo treatments. Depending on the administration time, pro-inflammatory cytokine productions by IL-4 can cause either inhibitory or stimulatory regulation.
TL;DR: In this article, the role of Newcastle disease virus (NDV) in the gut contents of day old chicks of different commercial hatcheries, and one NDV isolate from dead in shell embryos and one NB isolate from breeder hen were characterized and grouped under velogenic, mesogenic and lentogenic pathotypes.
Abstract: Newcastle disease virus (NDV) specific antigen in the gut contents and NDV specific antibody in blood circulation were seen in day old chicks belonging to nine different commercial hatcheries of Tamil Nadu, India. Antigen disappeared by 4th week and antibody by 6th week of age. Fourteen NDV isolates obtained from the gut contents of day old chicks of different commercial hatcheries, one NDV isolate from dead in shell eggs and one NDV isolate from breeder hen were characterized and grouped under velogenic, mesogenic and lentogenic pathotypes. Four isolates were grouped under F and another four isolates were grouped under E based on reaction with monoclonal antibodies (Mabs) but found to be velogenic based on pathogenicity tests. In one particular flock velogenie NDV was isolated from breeder hen, dead in shell embryos and day old chicks and they all belong to Mabs group E. Vertical transmission of velogenic, mesogenic and lentogenic NDVs and role of NDVs in the gut contents have been discussed.
TL;DR: Monoclonal antibodies were generated against the recombinant plasminogen activator (Pla) protein of Yersinia pestis and can be used for detecting Y. pestis isolates that are Fraction 1 antigen-negative.
Abstract: Monoclonal antibodies (MAbs) were generated against the recombinant plasminogen activator (Pla) protein of Yersinia pestis. These MAbs detected Pla in all the 18 isolates of Y. pestis obtained from the sputum of pneumonic plague patients and from the liver and spleen of rodents from plague-affected areas of India during 1994–1995 as well as in seven of the eight isolates obtained from rodents in the surveillance regions of Hosur and Palmner in India during 1998 by simple dot-ELISA. In immunoblotting, the MAbs reacted with the Pla antigen only in Y. pestis isolates at 37 and 35 kDa region. These monoclonal antibodies, being strictly specific, can be used for detecting Y. pestis isolates that are Fraction 1 antigen-negative. Also, the radiolabelled pla fragment hybridized specifically to the representative DNA samples of Y. pestis isolates.
TL;DR: The randomly amplified polymorphic DNA profiles showed no interstrain similarities between either strains of the B LS-producing L. innocua or the BLS-sensitive L. monocytogenes strains, suggesting inhibition of isolation of L. inocua after enrichment culture is unlikely to be dependent upon a particular genetic profile.
Abstract: Inhibition of isolation of Listeria monocytogenes by bacteriocin-like substance (BLS)-producing Listeria innocua after enrichment culture was investigated. When 26 L. monocytogenes strains were examined in combination with eight L. innocua strains using the spot on lawn method, 52/208 (25.0%) combinations showed the growth inhibition of L. monocytogenes. When two Listeria species were cultured simultaneously in selective enrichment broth, inhibition of isolation of L. monocytogenes was observed in 12/52 of the combinations at 24 h (23.1%), in 24/52 at 48 h (46.2%) and in 30/52 (57.7%) after 7 days of incubation. The randomly amplified polymorphic DNA profiles showed no interstrain similarities between either strains of the BLS-producing L. innocua or the BLS-sensitive L. monocytogenes strains. Therefore inhibition by BLS-producing L. innocua of isolation of L. monocytogenes after enrichment culture is unlikely to be dependent upon a particular genetic profile.
TL;DR: The results of this study indicate that short-term DEX-treatment increases leucocyte function; however, long-termDEX- treatment depresses leucocytes function, especially that of CD8(+) T cells.
Abstract: The aim of this study was to evaluate the effect of dexamethasone treatment on the immune system of weanling piglets. Piglets were administered dexamethasone (DEX; 1mg/kg, IM) every 12h for 2 consecutive days (short-term experiment) or DEX (1mg/kg, IM) daily for 2 weeks (long-term experiment). The relative percentage of CD8(+) T cells in peripheral blood mononuclear cells (PBMCs) was significantly decreased (P<0.05) in both short- and long-term DEX-treated groups compared to their control groups. The percentage of IgM(+) cells in PBMCs of the long-term DEX-treated group was greatly increased (P<0.05) in comparison to the control group. The results of this study indicate that short-term DEX-treatment increases leucocyte function; however, long-term DEX-treatment depresses leucocyte function, especially that of CD8(+) T cells.
TL;DR: The complete nucleotide sequence of the gene encoding the matrix protein (M) of the avian paramyxovirus, serotype 3b (APMV-3b), has been determined by means of the direct sequencing of viral RNA using reverse transcriptase reaction to show the closest relatedness towards Newcastle disease virus (NDV).
Abstract: The complete nucleotide sequence of the gene encoding the matrix protein (M) of the avian paramyxovirus, serotype 3b (APMV-3b), has been determined by means of the direct sequencing of viral RNA using reverse transcriptase reaction. The adjacent portions of the neighboring phosphoprotein (P) and fusion (F) protein genes were also sequenced that permitted to determine the consensus sequence of the viral genome, the poly(A) tract, downstream and upstream non-coding portions of the P and F genes, respectively, as well as the corresponding intergenic regions. The gene is 1478 nucleotides long with a protein-coding sequence of 1194 nucleotides. The deduced protein consists of 398 amino acids with a calculated MW 44,465. According to the multalignment and phylogenetic analyses, the APMV-3b M protein has shown the closest relatedness towards Newcastle disease virus (NDV) which has recently been suggested to be excluded from the Rubulavirus genus and assigned (together with APMV-6) to a new Avulavirus genus within the subfamily Paramyxovirinae of the Paramyxoviridae family. On the basis of the M protein genetic multalignment, phylogenetic relationships, bipartite nuclear localization signal identification in combination with the cysteine residues distribution, and by the degree of intrageneric heterogeneity, the APMV-3b is proposed to be another member (together with NDV and APMV-6) of the new genus.
TL;DR: The swine interleukin-4 (SwIL-4) cDNA was cloned by RT-PCR and the simple purification method will make it possible to evaluate the in vitro and in vivo effects of IL-4 in pigs.
Abstract: The swine interleukin-4 (SwIL-4) cDNA was cloned by RT-PCR. It was expressed using an expression vector pQE30 in E. coli, a baculovirus AcNPV vector pVL1392 in insect cells, and a pCAGGS vector in mammalian cells. The rSwIL-4 proteins expressed from bacteria and insect cells were purified using a chelating affinity column and a mAb-coupled immunoaffinity column. The amount of the products and their bioactivities were compared. All recombinant cytokines were efficiently reacted with the specific antibodies and the molecular weight of rSwIL-4 was approximately 16 kDa in E. coli, 15 and 18 kDa in insect cells, and 15 and 20 kDa in mammalian cells. Variations of molecular weight observed in insect and mammalian cells were probably due to different modification ways of glycosylation. All these recombinant proteins retained their antigenicity and were biologically active in inducing human TF-1 cell proliferation in vitro. The simple purification method will make it possible to evaluate the in vitro and in vivo effects of IL-4 in pigs.
TL;DR: A sandwich enzyme-linked immunosorbent assay (ELISA) for swine interleukin-6 (SwIL-6) was established, which was applied for detection of Swil-6 in vitro and in vivo and may be useful for understanding the role of this cytokine in various swine diseases.
Abstract: We established a sandwich enzyme-linked immunosorbent assay (ELISA) for swine interleukin-6 (SwIL-6), which was applied for detection of SwIL-6 in vitro and in vivo. Anti-SwIL-6 rabbit- and goat-polyclonal antibodies, and monoclonal antibody (mAb) were prepared, conforming that all of the antibodies were reactive with recombinant SwIL-6 by Western blotting and indirect ELISA. A sandwich ELISA was developed using the mAb as a capture antibody and biotinylated goat-polyclonal antibody as a detection antibody. The detection limit of the sandwich ELISA for rSwIL-6 was 49pg/ml and did not show cross-reactivity with swine IL-1b, IL-4, IL-8, IL-18, IL-12, and IFN-g. Using the ELISA, SwIL-6 was detected in culture medium of the monocytes stimulated with PHA-P and PMA, and the plasma or the bronchoalveolar lavage fluid (BALF) of pigs experimentally infected with Actinobacillus pleuropneumoniae or Mycoplasma hyopneumoniae. This ELISA for SwIL-6 may be useful for understanding the role of this cytokine in various swine diseases.
TL;DR: It was found that embryo vaccination can ensure definite protection during the early life of the chicks despite the presence of maternal antibodies.
Abstract: The effect of tuftsin of embryo and post-hatch vaccination with NDV-F was studied. The embryo vaccination with NDV-F resulted in more number of dead-in-shell embryos. To overcome this problem, the vaccine was treated separately with ethyl methane sulfate (EMS) and 5-fluorouracil (5-FU) and administered. Treating the vaccine with 5-FU resulted in better hatchability as compared to EMS treatment. In embryo, NDV antibody titres increased upto 2 weeks of age and declined thereafter, whereas in post-hatch vaccination, the antibody titre increased from second to fourth week of age and declined thereafter. The seroconversion was better when the vaccine was given along with tuftsin either to embryos or chicks (post-hatch vaccination) as compared to those vaccinated without tuftsin. Moreover, the percentage of hatchability was more in tuftsin administered groups. It was found that embryo vaccination can ensure definite protection during the early life of the chicks despite the presence of maternal antibodies. In cases where breeder vaccinations do not result in concomitant transfer of antibody to progeny chicks, embryo vaccination would give only neonatal resistance. During the later stages, embryo vaccination did not confer any advantage over post-hatch vaccination.