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1.
Pseudorabies virus hemagglutinin was readily adsorbed on mouse erythrocytes at 4, 22, or 37 degrees C, but not on cattle erythrocytes. The adsorbed hemagglutinin could not be eluted from the cells by resuspending in phosphate-buffered saline (PBS), by incubating at 37 or 50 degrees C, or by incubating in the presence of neuraminidase. The receptor on mouse erythrocytes for the hemagglutinin was inactivated by trypsin, but not by neuraminidase, sodium deoxycholate (DOC), potassium periodate (KIO4), dithiothreitol (DTT), 2-mercaptoethanol (2-ME) and formalin. The hemagglutinin was inactivated by trypsin, alpha-amylase, pepsin, DOC, KIO4, and ethylendiamine-tetraacetic acid (EDTA), but not by papain, beta-glucosidase, phospholipase C, neuraminidase, DTT, 2-ME, Tween-80, ethylether, chloroform, trichloro-trifluoroethane, beta-propiolactone and formalin, suggesting that the hemagglutinin active component involved glycoproteins. The hemagglutinin was stable at 37 degrees C for lower temperatures but not at 60 degrees C or higher. The hemagglutinin activity was resistant to ultraviolet irradiation, while the infectivity was very susceptible. The hemagglutinin and the infectivity were readily sedimented by ultracentrifugation at 48,000 x g for 3 hr. In rate zonal centrifugation of the preparation on a sucrose density gradient, the hemagglutination (HA) activity showed a sharp peak at 1.22 g/ml coinciding with the peak of infectivity. The HA activity in the peak fraction seemed to be structually associated with virus particles. After fractionation of the virus by Nonidet P-40, the HA activity was found only in the fraction of the envelope material, indicating that the hemagglutinin is situated in the viral envelop.  相似文献   

2.
Soma  T.  Hara  M.  Ishii  H.  Yamamoto  S. 《Veterinary research communications》2001,25(4):327-336
The application of the immunoperoxidase (IP) plaque staining procedure (IP test) to the diagnosis of canine coronavirus (CCV) infection was investigated. The IP test did not react with sera from either 15 specific pathogen-free (SPF) dogs or 7 SPF dogs immunized with a multivalent vaccine, including canine parvovirus type 2, canine distemper virus, canine adenovirus type 2, and canine parainfluenza virus. To compare the IP test with the neutralizing test (NT), sera from 240 healthy dogs and from 3 experimentally CCV-infected dogs were examined. All 60 sera positive for NT antibody were positive for IP antibody, and all 180 sera negative for NT antibody were negative for IP antibody in the healthy dogs. The IP titres showed similar changes with time after CCV inoculation to those of the NT titres in the experimentally infected dogs. These findings indicate that the IP test specifically detected anti-CCV antibodies. When the IP test and NT were compared in dogs with diarrhoeic signs. 2.1% of 48 sera and 20.3% of 74 sera, which were all negative for NT antibody, were positive for IP antibody in the dogs of under one year of age and at least one year of age, respectively. The difference between the IP and NT titres (log10 [reciprocal of IP titre] – log10 [reciprocal of NT titre]) for the diarrhoeic dogs of under one year of age (2.350±0.931) was significantly larger than that for the healthy dogs (0.982±0.447) (p<0.0001), the NT titre being negative or very low, despite a high IP titre in many diarrhoeic dogs. Hence, the IP test is more able to detect anti-CCV antibodies, especially in dogs showing clinical signs. The IP-positivity rate was significantly higher in the diarrhoeic dogs of under one year of age (48.7%) than in the healthy dogs (25.0%) (2 = 19.844, p<0.0001), suggesting that CCV may contribute to diarrhoea in many juvenile dogs.  相似文献   

3.
The kinetics of bovine viral diarrhea (BVD) virus neutralization (VN) by hyperimmune serum followed first order kinetics at low dilutions (1:8 and 1:16) of hyperimmune bovine serum. A lag phase in the VN curve occurred when the serum was further diluted. Addition of rabbit anti-bovine IgG, but not anti-IgM, significantly increased the degree of VN after BVD virus was reacted with further diluted (1:256 dilution) anti-BVD bovine hyperimmune serum. Incubation of virus-hyperimmune serum (1:64 dilution) at 4 degrees C for 0 to 60 min, followed by incubation at 37 degrees C indicated VN occurred as a two-stage process: a binding (temperature-independent) phase that was followed by a triggering (temperature-dependent) phase. The data favor the thesis that neutralization of BVD virus occurs by a multi-hit mechanism and requires combination of at least two molecules of antibody with each virus.  相似文献   

4.
Purification and some properties of a Bacillus cereus mouse lethal toxin.   总被引：2，自引：0，他引：2  
A mouse lethal toxin (MLT) produced by Bacillus cereus isolated in vomiting-type food poisoning was purified by chromatography on DEAE-Sephadex A-25 followed by gel filtration on Sephadex G-75. Purified MLT possessed a molecular weight of 33,000-34,000. It showed mouse lethality and hemolytic (HL) activity on sheep and rabbit erythrocytes; the latter erythrocytes were more weakly hemolyzed than the former ones. However, fluid accumulation in mouse ligated intestinal loops was not induced by purified MLT at the highest concentration used. Both MLT and HL activities were stable at pH 6-9, during storage at -20 degrees C for 8 weeks, and resistant to papain, cholesterol, lecithin, and dithiothreitol treatments. Most activity was lost during storage at 4 degrees C or 25 degrees C for 2 weeks or upon treatment with trypsin, trypanblue, or ethanol. The activities were resistant to heating at 37 degrees C for 5 min, less resistant at 98 degrees C for 5 min, and sensitive at 60 degrees C for 5 min. It can be concluded from the results that MLT is different from the diarrheagenic toxin produced by B. cereus isolated in diarrheal-type food poisoning, but is similar to, if not identical, hemolysin II.  相似文献   

5.
建立一种检测兔病毒性出血症病毒(RHDV)抗体的间接ELISA方法。对RHDV陕西分离株VP60基因进行原核表达,Western blot分析表达产物的免疫反应性;以纯化的蛋白为包被抗原建立ELISA方法,并对反应条件进行优化。结果表明,VP60蛋白在大肠杆菌中成功表达,产物约为42.34 ku的融合蛋白,具有良好的反应原性;优化的ELISA最佳工作条件为:重组抗原包被浓度2.9μg/mL,37℃2 h后4℃过夜,1%BSA 37℃封闭2 h,待检血清37℃孵育1 h,酶标抗体1∶10 000稀释,37℃作用1 h,37℃显色5 min,临界值为0.340;建立的ELISA方法特异性强、重复性好、敏感性高;临床检测180份样品,与血凝抑制试验的符合率为74.1%,与商品化试剂盒检测结果符合率为94.8%。该方法可用于临床样品的大批量检测。  相似文献   

6.
SUMMARY It was found possible to correlate serological responses to porcine parvovirus (PPV) with the time after infection. Two procedures were used for PPV antibody measurement: an immunodiffusion technique to measure precipitating antibody and a haemagglutination inhibition (Hl) procedure to measure concentration of 2-mercaptoethanol (2-ME) sensitive antibody. Both procedures successfully related antibody titres to time post-infection, but it was considered that a 2 M 2-ME HI procedure showed the greater promise for field investigations.  相似文献   

7.
The vaccination strain of infectious bursal disease virus, multiplied in cultures of chick embryo cells, was very resistant to heat. At a temperature of 56 degrees C the infection titre of the virus (TCID50) decreased by 0.9 log10 within two hours and by 1.2 log10 within five hours, but the virus remained infective still after 24 hours. At a temperature of 37 degrees C, a slight decrease in infection titre was recorded only after two days and a decrease by 1.2 log10 was recorded within ten days. After the 21st day the virus was almost inactivated. At a temperature of about 20 degrees C the infection titre of the virus decreased linearly from the third to the twelfth weeks. The control samples kept at +4 degrees C retained their infectivity for three months and at -20 degrees C even for six months. The discussion deals with the effect of the concentration of protein and magnesium chloride in the medium on the thermostability of infectious bursal disease virus.  相似文献   

8.
A panel of canine sera, the majority of which were collected from clinically healthy dogs, were investigated for antibodies against double stranded (dsDNA) by the Farr radioimmunoassay technique. Non-specific DNA binding agents interfering with the Farr assay were detected in all sera. Heat inactivation at 60 degrees C or treatment with dextran sulphate was shown to eliminate this kind of unspecific DNA binding while not affecting true antibodies to dsDNA. Canine sera positive in the Farr assay after inactivation at 60 degrees C were positive also in immunofluorescence for anti-nuclear antibody on rat liver sections and for dsDNA with Chrithidia luciliae as antigen preparation. IgG or glycoprotein nature of the non-specific DNA binding could be excluded by means of affinity chromatography on protein A and the lectin lentil.  相似文献   

9.
Pseudorabies virus (PRV) antibodies, detectable by indirect radioimmunoassay (IRIA), serum-virus neutralization test (NT), or microimmunodiffusion test (MIDT) were developed within 8 days after pigs were inoculated with virulent PRV or attenuated PRV vaccine. Indirect radioimmunoassay and NT titers in pigs inoculated with virulent PRV were developed at the same rate, with IRIA titers being higher than NT titers. Pigs inoculated with attenuated or inactivated PRV vaccine developed peak mean prechallenge NT antibody titers of 4 and 1 (reciprocals of serum dilutions), respectively. Pigs inoculated with attenuated PRV vaccine had peak mean prechallenge IRIA antibody titers of 6, whereas pigs inoculated with inactivated PRV vaccine had mean IRIA antibody titers of 64. Challenge exposure of swine inoculated with attenuated or inactivated PRV vaccine elicited quantitatively equivalent responses, as measured by IRIA or NT, which were higher than prechallenge titers. There were no false-positive IRIA, NT, or MIDT results obtained when sera from nonvaccinated, nonchallenge-exposed pigs were tested. It appears that the PRV infection status of a seropositive swine herd could be ascertained by serologically monitoring several representative animals from a herd, using the NT. If 2 or more tests of representative animals at 14-day intervals were done and the mean NT titer was 4 or less, it could be concluded that the herd was vaccinated against, but not infected with, virulent virus.  相似文献   

10.
Canine brucellosis is a contagious disease with venereal and oral modes of transmission that produces late abortion in females, epididymides and prostates in males. Diagnosis is difficult because of unstable serum antibody titers that vary from individual to individual as well as between different methods used for their detection. The objective of this work was to evaluate the clinical utility of the immunochromatographic assay (ICA) for serodiagnosis of dogs suspected of having brucellosis, and results were compared with those obtained for hemoculture (HC) and the rapid screening agglutination with 2-mercaptoethanol (2-ME RSAT). The all experimentally infected dogs were positive in ICA, HC and 2-ME RSAT from 5 weeks, 7 weeks, and 3 weeks after infection, respectively. Also, among dogs selected from 10 different breed kennels occurred brucellosis, 24.8%, 39.5% and 39.1% of dogs tested were detected as positive with HC, 2-ME RSAT and ICA, respectively. The kappa value between 2-ME RSAT and ICA was 0.89. The results of this study showed that sensitivity and specificity of the ICA are comparable with those obtained using conventional serological and bacteriological test for brucellosis. In conclusion, the ICA kit provides a handy and accurate tool for the rapid serodiagnosis of canine brucellosis.  相似文献   

11.
Gnotobiotic calves were inoculated by the intratracheal route with Mycoplasma bovis and the specific antibody response in sera and tracheo-bronchial washings examined by radioimmunoassay. In sera an IgM response which reached a peak two weeks post infection was followed by IgG1 and IgG2 antibody responses. Low levels of IgA antibody were detected in sera three and four weeks after infection. The predominant antibody in tracheo-bronchial washings 2 weeks after infection was IgA. Four weeks after infection IgG1 antibody predominated, but IgG2 and IgA antibodies were also present. Cells containing Ig were present in the cellular accumulations around the necrotic zones produced by M. bovis in the lung parenchyma two and four weeks after infection. IgG1 containing cells predominated in these cellular infiltrates. IgG2 producing cells were the next in frequency. It is concluded that the lung lesion caused by M. bovis is partly due to the host's immune response, presumably contributing to the control of the infection, and that the cells infiltrating the lung are a major source of the local and systemic IgG antibody that is detected after infection. IgA staining cells were observed in the submucosa of tissues from nasal cavity and trachea. These cells are probably the source of IgA in tracheo-bronchial washings and sera since IgA-producing cells were not a predominant component of the lesion in the lung parenchyma.  相似文献   

12.
Chronic elevation of uterine temperature has long been known to increase embryo mortality in dairy cattle. Short-term elevation in temperature of mouse embryos to 43 degrees C (acute) has been shown to induce intracellular production of heat-shock proteins. In this study, in vitro development of bovine embryos was assessed during short-term (60 h) coculture with oviduct epithelial cells at 38.6 degrees C (T1), 40 degrees C (T2), 38.6 degrees C after a prior pulse treatment (20 min) at 43 degrees C with 5% CO2 (T3), or 38.6 degrees C after a prior pulse treatment (20 min) at 43 degrees C with 100% CO2 (T4). During incubation, embryos cocultured at 40 degrees C had a greater (P < .05) mean embryo development score at 36 h than embryos cocultured at 38.6 degrees C. At 60 h of incubation, embryo development scores were greater (P < .05) for embryos cultured at 38.6 degrees C than for those cocultured at 40 degrees C. The number of embryos hatched at 60 h was similar after coculture at 38.6 degrees C (T1) or a prior pulse treatment with 5% CO2 and 43 degrees C (T3), but the embryo development score at 60 h was greater (P < .05) for the pulse-treated embryos. Embryos in T4 had greater (P < .05) embryo development scores than did T1 embryos from 36 through 60 h. Pulse treatment (T4) resulted in a greater (P < .05) number of hatched embryos at 60 h than T1, T2, and T3. These results indicate a detrimental effect of a chronic elevation in temperature that was evident shortly after embryo hatching.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

13.
An immuno-blot assay was used to investigate the serum antibody response in flounder injected with formalin-killed flagellates (immunized) and those injected with saline (control) and challenged with live T. bullocki after 21 days. Fish were held at 20 degrees C and at ambient temperature from October through June. At 20 degrees C immunized fish had significantly higher antibody titers than control fish, but immunized fish were not protected from infection with T. bullocki. At ambient temperature, after initial flagellate growth phase, antibody titer varied directly with temperature (2-25 degrees C) and T. bullocki intensity varied inversely with titer. Flagellates were eliminated from the peripheral circulation in both immunized and control fish when antibody titer peaked in May. Recovered fish were immune to homologous challenge for at least one year.  相似文献   

14.
Interferon, fluorescent antibody, and neutralizing antibody responses were studied in sera of 9 calves inoculated with bovine respiratory syncytial virus, in relation to viral shedding and clinical signs of disease. The calves (5.5 to 6.5 weeks of age) were assigned to 3 groups. Group I was inoculated once with the virus, and groups II and III were challenge exposed at postinoculation day (PID) 15 or 37. Serum-neutralizing and indirect fluorescent antibody techniques were used to measure antibody responses. The plaque-inhibition technique, using vesicular stomatitis virus, was applied to measure serum interferon titers. The virus was recovered by inoculation of nasal secretions onto cell cultures. Fluorescent antibody was detected in all calves on PID 3, with maximum titers appearing approximately on PID 10. Low neutralizing antibody was detected in most animals on PID 3, and titers peaked approximately 4.5 weeks after inoculation and then decreased. Interferon titers were high in all calves during the early stage of infection, dropped to undetectable amounts by PID 6, and reappeared in low amounts at least 1 week later. All infected calves manifested clinical signs of disease by PID 4 to 9. Clinical signs of disease were not observed after challenge exposure at PID 15 or 37, and anamnestic responses were not detected. Virus was recovered after challenge exposure at PID 15, but not at PID 37.  相似文献   

15.
An inactivated vaccine against rabbit haemorrhagic disease (RHD), developed and tested in our laboratory, is produced commercially by Bioveta, Ivanovice, Czechoslovakia. Rabbits developed full protection against infection 3 weeks after the administration of a single dose. Antibodies were detectable from day 5 after vaccination. Naturally acquired antibodies were demonstrated in some rabbits kept on commercial farms. The virus survived at least 225 days in an organ suspension kept at 4 degrees C, at least 105 days in the dried state on cloth at room temperature (around 20 degrees C), and at least 2 days at 60 degrees C, both in organ suspension and in the dry state. Experimental infection of rabbits younger than 2 months was successful in some animals. Hares, guinea pigs, white mice, golden and Chinese hamsters, chinchillas and hysterectomy-derived, colostrum-deprived piglets were resistant to infection.  相似文献   

16.
The antibody response to coproantigens of Cryptosporidium parvum was examined in saliva and sera of calves experimentally infected with C. parvum. Coproantigens of C. parvum with approximate molecular masses of 17, 15 and less than 14kDa were found in the feces of infected calves on day 3 or later, and 60 and 23kDa coproantigens observed between days 4 and 9 post-infection, respectively. The antibody reactivity to the coproantigens was mainly attributable to IgA class antibodies in saliva and was detectable during the convalescent phase of infection. A 15kDa protein isolated from the feces of infected calves by immunoaffinity adsorption using a monoclonal anti C. parvum antibody was recognized by IgA antibodies present in the saliva during the convalescent phase of infection. These results suggest that this coproantigen may be released from C. parvum sporozoites and may induce IgA antibody production in the mucosal immune system of infected calves.  相似文献   

17.
Single-cell suspensions of adult lizard (Chalcides ocellatus) spleen have been induced, in vitro, to produce a primary immune response. Using rat red cells (RRBC) as antigen and the culture conditions normally used in most vertebrate species but new for reptilia, it has been found that, in vitro at 37 degrees C, lizard spleen cells produce an antibody-forming response optimal at day 10. The response depends on the number of cultured cells and the dose of antigen, and parallels that obtained in vivo. Leibovitz (L-15) medium supplemented with 10% normal adult lizard serum was a satisfactory culture medium. 2-mercaptoethanol (2-ME), an ingredient used in mammalian cell culture, enhanced antibody production in lizard cells.  相似文献   

18.
Bovine interleukin 2: production and characterization   总被引：1，自引：0，他引：1  
The production of bovine IL 2 was studied and IL 2 was partially characterized. PMA at 5 ng/ml + Concanavalin A at 5 micrograms/ml treatment of peripheral blood mononuclear cells gave a greater yield of IL 2 activity in the supernatants than Con A, PMA or sodium periodate treatments alone. Macrophage depletion increased yields as did the addition of indomethacin, a prostaglandin E2 inhibitor. Bovine IL 2 was sensitive to trypsin, relatively stable at pH 2-9, 2-ME resistant and sensitive to increasing molar concentrations of urea. The activity of bovine IL 2 was reduced by over 45% at 70 degrees C for 30 min and 95% at 90 degrees C for 30 min. Bovine IL 2 was more stable at 4 degrees C than at room temperature and the stability at room temperature could be improved by inclusion of 1% BSA. Bovine IL 2 eluted from DEAE-Sephadex as a broad peak with 0.1-0.2 M NaCl. Peak activity corresponded to a molecular weight of approximately 16,000 daltons on Sephadex G-100.  相似文献   

19.
The hemagglutinating activity and serological properties of three strains of rabbit hemorrhagic disease virus, Chinese, Korean and Shizuoka, which was first isolated in Japan, were examined by hemagglutination (HA) and cross hemagglutination inhibition (HI) test with human erythrocytes. Similar results were observed between the Chinese and Korean strains, both of which gave positive HA at 4 degrees C with O, A, B and AB, and at 22 degrees C with B and AB blood groups. In the Shizuoka strain, positive HA was observed at 4 degrees C with O, A, B and AB, at 22 degrees C with A, B And AB, and at 37 degrees C with B blood group. In experimentally infected rabbits, HI antibody in these animals showed a titer of 16,384 or 32,768 at 4 weeks after inoculation. No serological difference was observed in three strains by cross HI test.  相似文献   

20.
The antibody response of 20 pregnant ewes to oocyst infection with Toxoplasma gondii was determined by the latex agglutination test (LAT) and compared with the indirect fluorescent antibody test (IFAT) and a commercially available indirect haemagglutination test (IHAT). The LAT and IFAT showed a similar rapid response with antibody first appearing by two to three weeks after infection and titres that correlated closely (r = 0.81, P less than 0.001). The IHAT response was slower and less consistent up to seven weeks after infection. The LAT response was biphasic in seven of the sheep. Sera were fractionated using a minicolumn gel filtration technique and specific IgM and IgG titres determined by LAT. IgM titres peaked three weeks after infection and IgG titres exceeded IgM titres at a mean time of 4.7 weeks after infection (range 3 to 7). Eleven sheep exhibited fetopathy with abortion/parturition 12 to 53 days after infection; in nine of them IgG titres exceeded IgM at that time. A non-specific anti-toxoplasma reaction associated with IgM antibody occurred at low titre in one sheep. The results indicate that used from a dilution of 1/64 the LAT is a sensitive, reliable and rapidly responsive serological test for toxoplasma infection in ewes and it may be utilised with sample fractionation techniques to determine IgM titres. It is suggested that the best time to examine ewe sera to assist diagnosis of toxoplasma abortion is one week after abortion. While the determination of specific IgM titres in ewe sera may assist epidemiological studies and, sometimes, diagnosis, in the majority of aborting ewe sera it is unlikely to aid diagnosis.  相似文献   

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