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1.

Background

The aim of the study was to provide a point of reference to study the Neospora caninum infections in China.

Methods

Genome DNA was extracted from the brains of aborted fetuses and specific PCR was performed with N. caninum Nc5-targeted specific primers. Fetal bovine brain tissues were homogenized and continuously cultured in Vero cells with double antibodies. The medium was replaced at 2-d intervals and the state of cells was observed.

Results

A 608 bp Nc5 gene band was detected by PCR amplification. After sequencing, the sequence of the sample shared 99.5% homology with GenBank (AF061249). Brain homogenates were continuously cultured in Vero cells for 34 d and N. caninum was found. The results of IFAT and Nc5 gene-based PCR detection were N. caninum-positive, and the parasite was tentatively named N. caninum China Yanbian strain. BABL/c mice were inoculated with the separated parasites and showed clinical symptoms of ataxia and limb paralysis after 12 d. Only 3 mice survived. The blood of dying mice and the hearts, livers, spleens, lungs, kidneys, and brains of dead mice were collected aseptically. The Nc5 gene-based PCR showed that N. caninum may exist in brains, livers, and spleen. Based on immunohistochemical observations, we showed that N. caninum tachyzoites existed in the brains and livers.

Conclusion

We have successfully isolated bovine-specific N. caninum strain from brain tissues of aborted cattle in the China Yanbian region. This isolated strain has a strong infectious ability towards BABL/c mice.  相似文献   

2.

Background

The aim of this study was to determine the seroprevalence of antibody to Neospora caninum in healthy and aborted dairy cattle in Tabriz, capital of East-Azarbaijan in northwest of Iran.

Methods

In this cross-sectional study serum samples were collected from 266 healthy and aborted Holestein-Feriesisnc cows from September 2008 to August 2009. The sera were analyzed to detect of antibody against N. caninum using the commercially ELISA kit.

Results

Seroprevalence of antibody to N. caninum was 10.5% in Tabriz dairy cattle. Also the abortion rate in all cattle sampled was 33.6% but percentage of seropositive aborted cattle was 18.4%.

Conclusion

Neosporosis could be one of the possible causes of abortion in dairy cattle in Tabriz and regarding the distribution in dogs as definitive host for the parasite, further studies in dog and cattle are recommended.  相似文献   

3.

Background:

Dense granules are immunodominant proteins for the standardization of immunodiagnostic procedures to detect neosporosis. In the presented study different fragment of a dense-granule protein was evaluated for serodiagnosis of Neospora caninum in cattle and water buffalo.

Methods:

NcGRA7, from N. caninum tachyzoites was amplified. PCR product and pMAL-c2X plasmid were digested with EcoR1 restriction enzyme and expressed in Escherichia coli to evaluate its competence for detection of anti- N. caninum antibodies with ELISA in comparison with commercial IDEXX ELISA. Furthermore, 230 sera of presumably healthy cattle and water buffaloes (108 cattle and 122 water buffaloes) were analyzed by both tests to determine the agreement of these two procedures.

Results:

Sensitivities and specificities of NcGRA7-based ELISA were 94.64% and 90.38% respectively using sera of cattle, but were 98.57% and 86.54% in the case of buffaloes respectively. A good correlation between the results of IDEXX ELISA and ELISA based on recombinant NcGRA7 for detecting N. caninum antibodies was appeared. Analyzing by Mc Nemar′s showed that NcGRA7-based ELISA has acceptable capability to differentiate the positive results in comparison with IDEXX ELISA.

Conclusion:

NcGRA7-based ELISA considering utilized new fragment of genomic DNA is a good tool for serodiagnosis of anti- N. caninum antibodies for screening and epidemiological purposes on cattle herd and water buffaloes as well.  相似文献   

4.
5.
Tuo W  Zhao Y  Zhu D  Jenkins MC 《Vaccine》2011,29(13):2392-2399
Neospora caninum is the causal agent of bovine neosporosis which results in high levels of abortion. The present study determined the protective efficacy of two Neospora antigens - Neospora cyclophilin (NcCyP) and NcSRS2. The ability of native NcCyP to upregulate mouse IFN-γ was also confirmed in this study. Recombinant NcCyP or NcSRS2 were tested either alone or in combination and formulated with adjuvant ImmuMax-SR and CpG. Female BALB/c mice (n = 15) of 10-12 weeks of age were immunized s.c. twice over a 2-week interval with vaccines containing either NcCyP (20 μg/dose) alone, NcSRS2 (20 μg/dose) alone, NcCyP plus NcSRS2, or non-recombinant bacterial antigen (NR) in 2 separate trials. All mice were challenge-infected 3 weeks following the booster immunization and necropsied 3 weeks after the challenge infection. Brain and serum were collected and Nc-specific DNA sequence in brain tissue and antibodies in serum were analyzed by PCR or ELISA/Western blotting. Results showed that mice vaccinated with rNcCyP, rNcSRS2, or both rNcCyP and rNcSRS2 responded with high levels of NcCyP or NcSRS2 specific antibodies. Overall, mice received vaccines formulated with either rNcCyP or rNcCyP and rNcSRS2 had a higher (p < 0.01) percent protection when compared to the mock- or non-vaccinated mice. The group immunized with rNcSRS2 alone exhibited slightly lower levels of protection, which was higher (p < 0.05) than that of the non-vaccinated group but did not differ (p = 0.06) from that of the mock-vaccinated group. The results of the present study indicate that NcCyP is a highly efficacious vaccine candidate which may be useful in protection against Neospora infection.  相似文献   

6.
ArtinM and Jacalin (JAC) are lectins from the jackfruit (Artocarpus integrifolia) that have important role in modulation of immune responses to pathogens. Neospora caninum is an Apicomplexa parasite that causes neuromuscular disease in dogs and reproductive disorders in cattle, with economic impact on the livestock industry. Hence, we evaluated the adjuvant effect of ArtinM and JAC in immunization of mice against neosporosis. Six C57BL/6 mouse groups were subcutaneously immunized three times at 2-week intervals with Neospora lysate antigen (NLA) associated with lectins (NLA + ArtinM and NLA + JAC), NLA, ArtinM and JAC alone, and PBS (infection control). Animals were challenged with lethal dose of Nc-1 isolate and evaluated for morbidity, mortality, specific antibody response, cytokine production by spleen cells, brain parasite burden and inflammation. Our results demonstrated that ArtinM was able to increase NLA immunogenicity, inducing the highest levels of specific total IgG and IgG2a/IgG1 ratio, ex vivo Th1 cytokine production, increased survival, the lowest brain parasite burden, along with the highest inflammation scores. In contrast, NLA + JAC immunized group showed intermediate survival, the highest brain parasite burden and the lowest inflammation scores. In conclusion, ArtinM presents stronger immunostimulatory and adjuvant effect than Jacalin in immunization of mice against neosporosis, by inducing a protective Th1-biased pro-inflammatory immune response and higher protection after parasite challenge.  相似文献   

7.
In order to achieve host cell entry, the apicomplexan parasite Neospora caninum relies on the contents of distinct organelles, named micronemes, rhoptries and dense granules, which are secreted at defined timepoints during and after host cell entry. It was shown previously that a vaccine composed of a mixture of three recombinant antigens, corresponding to the two microneme antigens NcMIC1 and NcMIC3 and the rhoptry protein NcROP2, prevented disease and limited cerebral infection and transplacental transmission in mice. In this study, we selected predicted immunogenic domains of each of these proteins and created four different chimeric antigens, with the respective domains incorporated into these chimers in different orders. Following vaccination, mice were challenged intraperitoneally with 2 × 106N. caninum tachzyoites and were then carefully monitored for clinical symptoms during 4 weeks post-infection. Of the four chimeric antigens, only recNcMIC3-1-R provided complete protection against disease with 100% survivors, compared to 40-80% of survivors in the other groups. Serology did not show any clear differences in total IgG, IgG1 and IgG2a levels between the different treatment groups. Vaccination with all four chimeric variants generated an IL-4 biased cytokine expression, which then shifted to an IFN-γ-dominated response following experimental infection. Sera of recNcMIC3-1-R vaccinated mice reacted with each individual recombinant antigen, as well as with three distinct bands in Neospora extracts with similar Mr as NcMIC1, NcMIC3 and NcROP2, and exhibited distinct apical labeling in tachyzoites. These results suggest that recNcMIC3-1-R is an interesting chimeric vaccine candidate and should be followed up in subsequent studies in a fetal infection model.  相似文献   

8.
At present, there is no effective treatment or vaccine to prevent vertical transmission or abortion associated with Neospora caninum infection in cattle. Different vaccine formulations have been assayed, and live vaccines have shown the most promising results in terms of protection. Previously, transgenic N. caninum tachyzoites expressing the bradyzoite stage-specific NcSAG4 antigen in a constitutive manner (Nc-1 SAG4c) were obtained and showed a reduced persistence of parasite in inoculated mice. Thus, the present study evaluates the Nc-1 SAG4c1.1 and Nc-1 SAG4c2.1 transgenic strains and the Nc-1 wild-type (WT) strain to determine their protective efficacy against vertical transmission and cerebral neosporosis in mice. Consequently, dams were immunized twice with 5 × 105 tachyzoites of each strain and challenged with 2 × 106 tachyzoites of a heterologous and virulent isolate at 7-10 days of gestation. The Nc-1 SAG4c1.1 strain offered less protection than the other transgenic strain (Nc-1 SAG4c2.1) or their ancestor (Nc-1 WT). Indeed, 40%, 7% and 5.6% of the postnatal deaths corresponded to pups from dams vaccinated with Nc-1 SAG4c1.1, Nc-1 SAG4c2.1 and Nc-1 (WT) strains, respectively. In comparison, the non-immunized challenge group had a 100% mortality rate. In addition, mice were protected against congenital transmission; vertical transmission rates were 45%, 11.1% and 10.8% in the Nc-1 SAG4c1.1, Nc-1 SAG4c2.1 and Nc-1 WT immunized groups, respectively, vs. 94.9% in the non-vaccinated infected group. However, this protection against the postnatal mortality and the vertical transmission was not associated with a consistent Th1 or Th2-type immune response. Nonetheless, the Nc-1 SAG4c2.1 strain appears to be the best candidate for use as a live vaccine, as evidenced by results demonstrating its high levels of protection against vertical transmission and its lower persistence in mice, making this transgenic strain safer than Nc-1 WT.  相似文献   

9.

Background

Neospora caninum is a protozoan parasite from phylum apicomplexa and an important agent causing abortion in cattle which produce notable economic loss all around the world.

Methods

Dot-Elisa was set up performing checker board procedure and then 178 sera of cattle examined with commercial indirect ELISA and direct agglutination test (DAT) were also evaluated by dot-ELISA afterwards.

Results

Kappa statistical analysis revealed that Dot-ELISA has good agreements with ELISA as well as the DAT and also, Mc Nemar’s analyzing showed that this procedure has acceptable ability to discriminate positive results. Relative sensitivity and specificity of Dot-ELISA were respectively 92.63% and 89.16% and 93.4% and 90.8% in comparison with ELISA and DAT.

Conclusion

Since the dot-ELISA is easy, inexpensive and not needed high experience to interpret the results, it is superior to ELISA and DAT when we aim to screen the cattle on the farm and slaughterhouses or when the laboratory equipment is not available.  相似文献   

10.
CpG oligodeoxynucleotides (ODN) have shown to be potent immunoadjuvants for several pathogens, but there is limited information concerning their use in immunization protocols against neosporosis. This study aimed to evaluate the potential of CpG-ODN combined with Neospora lysate antigen (NLA) or excreted-secreted antigen (NcESA) to induce protective immune response against Neospora caninum infection in mice. C57BL/6 mice were vaccinated subcutaneously three times at 2-week intervals with NLA, NLA + CpG, NcESA, NcESA + CpG, CpG (adjuvant control) or PBS (infection control). Serological assays showed an increased specific IgG2a response in animals immunized with either antigen plus adjuvant and elevated levels of the IgG1 isotype in those vaccinated with antigens alone. Splenocyte proliferative responses upon antigen stimulation were higher in groups immunized with NLA or NcESA combined with CpG, showing increased IL-12 levels. Also, mice vaccinated with NcESA or NcESA + CpG demonstrated higher IFN-γ levels and IFN-γ/IL-10 ratio. After lethal challenge, mice immunized with NLA + CpG or NLA had lower morbidity score and body weight changes in comparison to other groups, and animals did not succumb during acute infection. In contrast, NcESA + CpG or NcESA groups exhibited the highest morbidity scores, body weight impairment and mortality rates, associated with greatest brain parasite burden and inflammation. In conclusion, CpG-ODN was able to induce a Th1-type humoral immune response with predominant IgG2a levels for either NLA or NcESA, but resulting in an effective Th1-driven cellular immune response and total protection only when combined with NLA. Vaccination with NcESA alone or combined with CpG resulted in a strong cellular immune response associated with high levels of IFN-γ and inflammation, rendering mice more susceptible to parasite challenge.  相似文献   

11.

Background

Neospora caninum, an obligate intracellular protozoan parasite, is recognized as a major cause of abortion in cattle, while limited information is presently available on the seroprevalence of Neospora antibodies in horses’ worldwide. The aim of the present study was to determine serologic prevalence of Neospora infection in horses in Iran.

Methods

Sera from 150 horses from Mashhad suburb in Razavi Khorasan Province, northeast Iran were examined for antibodies to Neospora spp. using Neospora modified direct agglutination test (N-MAT).

Results

Antibodies to this parasite were detected in 45 (30%) of the examined serum samples. Thirty four percent of the samples had titer of 1:40 while then reduced to 30% when 1:80 serum dilution was applied as significant cut off titer.

Conclusion

This study is the first investigation carried out on the Neospora in horses in Iran and indicates that horses in Iran are exposed to this parasite.  相似文献   

12.
The major route of transmission of Neospora caninum in cattle is transplacentally from an infected cow to its progeny. Therefore, a vaccine should be able to prevent both the horizontal transmission from contaminated food or water and the vertical transmission. We have previously shown that a chimeric vaccine composed of predicted immunogenic epitopes of NcMIC3, NcMIC1 and NcROP2 (recNcMIC3-1-R) significantly reduced the cerebral infection in BALB/c mice. In this study, mice were first vaccinated, then mated and pregnant mice were challenged with 2 × 106N. caninum tachyzoites at day 7–9 of pregnancy. Partial protection was only observed in the mice vaccinated with a tachyzoite crude protein extract but no protection against vertical transmission or cerebral infection in the dams was observed in the group vaccinated with recNcMIC3-1-R. Serological and cytokine analysis showed an overall lower cytokine level in sera associated with a dominant IL-4 expression and high IgG1 titers. Thus, the Th2-type immune response observed in the pregnant mice was not protective against experimental neosporosis, in contrary to the mixed Th1-/Th2-type immune response observed in the non-pregnant mouse model. These results demonstrate that the immunomodulation that occurs during pregnancy was not favorable for the protection against N. caninum infection conferred by vaccination with recNcMIC3-1-R.  相似文献   

13.
Efficient, cost-effective and safe Th1-immunity-inducing vaccine formulations are paramount for achieving protection against Neospora caninum. In this study, a new adjuvant (Providean-AVEC®) was used in the development of a N. caninum vaccine and evaluated in a mouse model. Soluble N. caninum tachyzoite native protein extract (sNcAg) was selected as vaccine antigen based on its capacity to activate production of pro-inflammatory cytokines on dendritic cells. Vaccines containing 4 and 0.4 μg of sNcAg, and Providean-AVEC®, ISCOM-Matrix or aluminum hydroxide (Alum) were tested in BALB/c mice. While mice vaccinated with 4 μg of sNcAg + Providean-AVEC® developed specific antibodies shortly after the first dose, the rest of the high antigen payload formulations only induced seroconversion after the booster. Mice immunized with the high payload ISCOM vaccine (4 μg sNcAg) or with either low or high payload Providean-AVEC® formulations (0.4 μg and 4 μg sNcAg, respectively) elicited higher IgG2a than IgG1 serum levels, and IFN-γ anamnestic responses with a Th1-cytokine biased profile. These animals had no histological signs of cerebral lesions and parasite burden assessed by quantitative real-time PCR was not detected. Vaccine preparations including Providean-AVEC® as adjuvant limited N. canimum multiplication even with only a tenth of antigen payload compared to vaccines containing other adjuvants. Using adjuvants to specifically activate dendritic cells, combined with a careful antigen selection can enhance cellular responses to inert N. caninum vaccines.  相似文献   

14.
Retrospective testing of 3,232 serum samples from the general population and 518 serum samples from a high-risk group showed no evidence of human exposure to Neospora caninum in England. Results were obtained by using immunofluorescence antibody testing and ELISA to analyze frequency distribution.  相似文献   

15.
Toxoplasma gondii and Neospora caninum are closely related apicomplexan parasites. The surface antigen 1 of T. gondii (TgSAG1) is a major immunodominant antigen and, therefore, is considered to be a good candidate for the development of an effective recombinant vaccine against toxoplasmosis. In this study, N. caninum stably expressing the TgSAG1 gene (Nc/TgSAG1) was constructed using pyrimethamine-resistant DHFR-TS and GFP genes as double-selection markers. The expression level, molecular weight, and antigenic property of recombinant TgSAG1 expressed by the Nc/TgSAG1 were similar to those of the native TgSAG1. The mice immunized with Nc/TgSAG1 induced TgSAG1-specific Th1-dominant immune responses and protected the mice from a lethal challenge infection with T. gondii. These results indicate that N. caninum may provide a new tool for the production of a live recombinant vector vaccine against toxoplasmosis in animals. To our knowledge, this is the first report to evaluate the usefulness of N. caninum-based live vaccine.  相似文献   

16.
Neospora caninum is an intracellular protozoan parasite that causes abortion in cows. Vaccination is an important strategy for control of neosporosis, and a safe and effective vaccine suitable for cattle is required. Dense granule protein 7 of N. caninum (NcGRA7) is a secretory protein with high antigenicity in hosts. We demonstrated previously that NcGRA7 entrapped in liposomes coated with mannotriose (M3-NcGRA7) could induce a parasite-specific T-helper type 1 immune response and produce humoral antibodies that resulted in increased offspring survival and decreased infection in the brains of mice dams. In the present study, the efficacy of M3-NcGRA7 as a vaccine candidate against N. caninum has been evaluated in cattle (n = 12). Cattle were immunized with M3-NcGRA7 containing 50 μg (n = 4) or 200 μg NcGRA7 (n = 4) subcutaneously twice with a 4-week interval and all cattle including the non-immunized controls (n = 4) were inoculated with 107 tachyzoites of Nc-1 strain 27 days after the second immunization and euthanized at 85–87 days post infection (dpi). In immunized cattle, NcGRA7-specific antibody production and IFN-γ production in PBMC was induced before challenge. At 3 dpi, body temperature and concentration of serum IFN-γ tended to be higher in control cattle than in the immunized cattle. Furthermore, the parasite load in the brain significantly decreased in cattle immunized with 50 μg M3-NcGRA7 compared with controls. These results suggest that M3-NcGRA7 can induce protective immune responses to N. caninum tachyzoites in cattle, which could lead to practical application of safe and effective subunit vaccines.  相似文献   

17.
18.
The development of an effective vaccine against Neospora caninum infection in cattle is an important issue due to the significant economic impact of this parasitic disease worldwide. In this work, the immune response, safety and efficacy of different vaccine formulations using the N. caninum recombinant proteins rNcSAG4 (the first bradyzoite-specific protein assayed as a vaccine) and rNcGRA7 were evaluated in mouse models. The survival curves of pups from all vaccinated groups showed a slight delay in time to death compared to control groups; this difference was statistically significant for rNcSAG4 + adjuvant group. Immune response of mice vaccinated with rNcSAG4 was characterized by reduced specific IgG and cytokine levels with an equilibrated IFN-gamma/IL-10 balance. Regarding mice vaccinated with rNcGRA7, a very strong humoral and cellular immune response was generated characterized by a hyper-production of IFN-gamma. This response was not accompanied by significant protection. Vaccination with a mixture of both recombinant proteins reduced infection in lung and brain during acute and chronic infection, respectively, although it was not statistically significant. In summary, no significant protection was obtained with these vaccine formulations in the present mouse models. However, the study reveals some positive results on immune response and efficacy for both recombinant proteins; these results are being discussed in order to suggest new approaches with new chronic infection mouse models and adjuvants.  相似文献   

19.

Background

Toxoplasma gondii, the obligate intracellular parasite is life threatening in AIDS patients. Diagnosis of toxoplasmosis is based on serological methods especially increasing of IgM and IgG titers, but finding of parasite or its components (antigenemia) may be beneficial method in order to detection of acute toxoplasmosis in immunocompromised patients.

Methods

Ninety-four serum samples from HIV positive patients were collected from Sanandaj, Kordistan west of Iran. These patients were lived in Sanandaj of whom 26 were prisoners infected with HIV virus in prison. Toxoplasma gondii antibodies were determined by IgG ELISA. T. gondii antigen was identified by capture-ELISA. PCR was performed on samples with T. gondii antigenemia. CD4+ T cells counts had been determined by flowcytometry and were obtained from records of each patient.

Results

Among the examined HIV seropositive individuals, 19.1% (18/94) and 5.3% (5/94) were positive for Toxoplasma-IgG and antigenemia, respectively. Besides, one of the samples was positively detected by PCR method. Mean age of participants was 37.9 ± 9.5 year. Prevalence of IgG antibody and antgenemia was higher in age group of 40-50 years old. The Mean of CD4+ T cells counts of participants (total of HIV+ patients, IgG positive patients and patients with antigenemia) was 699.2 ± 345.2, 655.1 ± 237.9 and 620.2 ± 215.1 respectively.

Conclusion

Capture-ELISA and PCR could confirm the T. gondii acute infection in HIV positive patients. For precise diagnosis of acute toxoplasmosis in HIV positive patient, performance of more studies based on more sensitive types of PCR is suggested.  相似文献   

20.

Background

Toxoplasmosis is a major public health problem among immuno-compromised individuals. This study aimed to determine the seroprevalence and associated risk factors of Toxoplasma gondii infection among pregnant women with and out HIV infections.

Methods

This cross sectional study was conducted among consecutive 385 pregnant women attended Antenatal Clinic from May 2010 to October 2011 at the Gondar University Teaching Hospital, Northwest Ethiopia. Venous blood was collected from each pregnant woman for testing HIV-1/2 and anti- Toxoplasma antibodies using rapid test kits. Data were entered and analyzed using SPSS version 20 statistical package.

Results

The overall magnitude of T. gondii and HIV was 88.6% (341/385) and 11.2% (43/385), respectively. The seroprevalence of T. gondii was not different among HIV infected and non-infected pregnant women (88.4%, 38/ 43 vs 88.6%, 303/342). Keeping cats in house showed statistically significant association with seropositivity of toxoplasmosis (P<0.05).

Conclusion

Irrespective of HIV infection, high rate of T. gondii was detected among pregnant women. These high prevalences indicate the need for an intensified public health awareness to reduce both infections.  相似文献   

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