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1.
Abstract

Rabbit antisera against viral hemorrhagic septicemia virus (VHSV) produced by two immunization procedures were compared for neutralization and immunochemical properties against homologous and heterologous strains. The VHSV isolate used as the immunogen was a member of a serogroup not neutralized by previously available antisera. The results from this study suggested that frequent intravenous (IV) injections of rabbits with viral antigens were superior to adjuvant-mediated, combined subcutaneous and intraperitoneal (SC/IP) injections for the production of neutralizing antisera. All IV injected rabbits produced high neutralization titers against the homologous VHSV isolate but not against an isolate from a different serogroup. The SC/IP injected rabbits had no significant neutralization titers against either the homologous VHSV strain or two isolates of a heterologous VHSV strain. Sera from all injected rabbits reacted in indirect immunofluorescence (IF) assays with either strain; however, the SC/IP injected rabbits produced higher titers against the heterologous VHSV strain by ELISA (enzyme-linked immunosorbent assay). By Western blotting, neutralizing antisera primarily stained the viral glycoprotein (G) whereas the nonneutralizing sera stained all the viral structural proteins equally well. Our results demonstrate that immunization procedures to produce antisera against VHSV in rabbits determine whether the resultant antibodies will have primarily neutralizing or binding capabilities.  相似文献   

2.
Antisera raised in rabbits against the porcine enterovirus strains V13 and T80 produced two precipitin lines in immunodiffusion tests with the homologous crude antigens, and a single precipitin line with each of ten heterologous porcine enteroviruses which were tested, and with poliovirus type 1, coxsackievirus B4 and equine rhinovirus type 1, but not with a bovine rhinovirus. C and D antigens prepared from V13 virus by density gradient centrifugation produced single precipitin lines with V13 antiserum. A single precipitin line was also formed when the heated crude antigens of V13 and T80 viruses were reacted with the homologous antisera, indicating destruction of the D antigen, and these lines fused with those produced by the heterologous viruses. It was concluded that porcine enteroviruses contain C and D antigens, and that the C antigen is responsible for the serological cross-reactivity demonstrated among porcine enteroviruses and other picornaviruses by immunodiffusion.  相似文献   

3.
通过兔制备了３株引起鸡败血症的埃希氏大肠杆菌（Ｅ．ｃｏｌｉ）高免血清,对分离自新疆不同地区的３０余株鸡致病性Ｅ．ｃｏｌｉ进行了玻板凝集试验和双向免疫扩散试验。结果证明,在琼扩试验中,不同的Ｅ．ｃｏｌｉ菌株间存在着同源性抗原成份,这种同源性抗原在绝大多数Ｅ．ｃｏｌｉ间都有数种之多。但是,这种相互间的同源抗原在玻板凝集试验中有时并不能表现,甚至有沉淀线出现的血清与抗原之间在玻板凝集试验中也不能检测出来。  相似文献   

4.
Strains of rinderpest virus (RV) with high and low virulence were compared with cell culture-attenuated RV for antigenic differences. Sera collected from rabbits 1 week after inoculation with live virus distinguished between homologous and heterologous strains by kinetic neutralisation and competition ELISA.  相似文献   

5.
In studies to determine whether vaccination with one strain of Moraxella bovis would protect against challenge with virulent homologous or heterologous strains, calves were intramuscularly inoculated 3 times with formalin-killed M bovis, with 14 days between inoculations. Fourteen days after the 3rd vaccinal dose was given, all calves were exposed to homologous or heterologous virulent cultures of M bovis. The results indicated that vaccination with one strain of M bovis may induce protective immunity against homologous and heterologous challenge exposure; however, because vaccinated cattle resisted infection and disease produced by a homologous strain to a greater extent than they resisted those produced by heterologous strains, polyvalent vaccines or highly immunogenic common antigens may be needed to protect cattle against the numerous strains they might encounter under natural field conditions. There was minimal correlation between the presence of precipitating antibodies against the heterologous strains and the establishment of infection and disease.  相似文献   

6.
Fourteen enteropathogenic and five nonenterotoxigenic Escherichia coli strains isolated from pigs were used for producing antisera in rabbits and pigs. These antisera were used in an vitro test system for antibacterial activity against homologous and heterologous porcine E. coli strains. Antibacterial titres were determined against the homologous strains and the percent reduction in CFU/ml caused by a 1/200 dilution of the sera against heterologous strains was determined. The results indicated that following immunization the antibacterial activity of serum against homologous and heterologous strains was significantly increased. This activity did not appear to be influenced by O and K antigen relationships among the organisms or by enterotoxigenicity of the vaccine strains. When antiserum produced against a combination of three enteropathogenic E. coli was tested against 20 strains a wider spectrum of heterologous antibacterial activity was obtained than with antiserum produced against any individual strain. The results indicate the existence in E. coli strains of porcine origin of common antigenic determinants not related to the serological formula and that a selected combination of strains can be expected to induce antibacterial acitivity against a wide variety of serological types of porcine enteropathogenic E. coli.  相似文献   

7.
Counterimmunoelectrophoresis, direct immunofluorescence and immunodiffusion procedures were used to serotype 15 strains of Haemophilus pleuropneumoniae isolated from the respiratory tract of pigs in southern Brazil. Antigens were prepared by extracting cultures with a saline solution or by the phenol-water method. Antisera were prepared in rabbits against serotypes 1, 2, 3 and 5. Thirteen of the isolates were type 5 and two were type 3. No differences were observed between the results obtained in serotyping with counter immunoelectrophoresis and direct immunodiffusion, but both procedures were significantly better than immunodiffusion except with the saline extracted antigen. Counterimmunoelectrophoresis was quicker, more sensitive and more easily performed than the other techniques.  相似文献   

8.
Vaccination is a useful option to control infection with porcine reproductive and respiratory syndrome virus (PRRSV), and several modified live-PRRSV vaccines have been developed. These vaccines have shown some efficacy in reducing the incidence and severity of clinical disease as well as the duration of viremia and virus shedding but have failed to provide sterilizing immunity. The efficacy of modified live-virus (MLV) vaccines is greater against a homologous strain compared with heterologous PRRSV strains. The objective of this study was to evaluate the efficacy of Fostera PRRS MLV vaccine in protecting against challenge with a heterologous field strain widely circulating in the swine herds of eastern Canada. Forty-six piglets were divided into 4 groups: nonvaccinated-nonchallenged; nonvaccinated-challenged; vaccinated-challenged; and vaccinated-nonchallenged. The animals were vaccinated at 23 d of age with Fostera PRRS and challenged 23 d later with a heterologous field strain of PRRSV (FMV12-1425619). Overall, the vaccine showed some beneficial effects in the challenged animals by reducing the severity of clinical signs and the viral load. A significant difference between nonvaccinated and vaccinated animals was detected for some parameters starting 11 to 13 d after challenge, which suggested that the cell-mediated immune response or other delayed responses could be more important than pre-existing PRRSV antibodies in vaccinated animals within the context of protection against heterologous strains.  相似文献   

9.
Nineteen antisera produced in pigs against 14 enteropathogenic and five nonenterotoxigenic porcine strains of Escherichia coli were tested for their ability to inhibit gut loop fluid accumulation induced by homologous and heterologous organisms. In addition, four antisera produced in pigs by an intensive series of intravenous inoculations and three by a less intensive series of intramuscular injections of a polyvalent E. coli vaccine were evaluated. Antisera were also produced in rabbits against eight strains of porcine enteropathogens and tested in pig gut loops. Fluid inhibiting activity was detected in prevaccinal sera of pigs but not of rabbits. This activity was significantly increased following immunization. When single strains of E. coli were used for immunization the activity of the antisera against heterologous organisms varied considerably from one test strain to another and was usually much less than that against the homologous organism. The activity against heterologous organisms could not be associated with relatedness of the O, K and H antigens of the vaccine and the test strains. Antisera produced against a vaccine made by combining three strains were shown to exert inhibitory effects on heterologous organisms similar to those against homologous organisms. Considerably less activity against homologous and heterologous organisms was present in antisera produced by the series of intramuscular compared with the series of intravenous injections.  相似文献   

10.
Single-oocyst-derived field strains of Eimeria tenella isolated from Rugby in the United Kingdom (E tenella R) and from Mymensingh and Dhaka in Bangladesh (E tenella M and D, respectively) and a laboratory strain (E tenella, Houghton, H) were compared by isoenzyme electrophoresis, reactivity with antisporozoite monoclonal antibodies and, for some pairs of strains, cross-protection in vivo. The three field strains conformed to one zymodeme with respect to six isoenzymes. For glucose phosphate isomerase (GPI) all field strains were characterised by GPI-9. A panel of six different monoclonal antibodies raised against sporozoites of E tenella H did not discriminate between strains by titration in an immunofluorescence assay against air-dried, acetone fixed sporozoites. In cross-protection experiments involving immunisation and challenge of young chickens, two immunisation schedules were used which, after homologous challenge, provided complete immunity either by the criterion of oocyst output, or by the criterion of weight gain (and more than 94 per cent protection by the criterion of oocyst output). While strain heterogeneity was minimal in the former situation, there was poor cross protection between some strains in the latter case. Under those conditions, heterologous challenge with E tenella M resulted in dysentery and in significantly (P less than 0.05) increased oocyst output and decreased weight gain. The results suggested that E tenella M was immunologically superior to E tenella R and H strains. The results show that a limited degree of immunogenic variability exists between these strains of E tenella and that, unless homologous strain immunity is complete by the criterion of oocyst output, challenge with heterologous strains may result in depressed weight gain.  相似文献   

11.
Feline calicivirus (FCV) is characterised by a high degree of antigenic variation potentially compromising vaccine efficacy. Inclusion of several FCV strains or antigens in current vaccines could be a means to improve protection against antigenically distinct isolates. This study evaluated the synergy between two FCV strains (FCVG1 and FCV431) by comparing immunity induced by either strain with that provided by a combination of the two strains against an heterologous challenge with antigenically distant FCV strains (FCV393 and FCV220). Thirty-two SPF kittens were randomly allocated to four groups of eight cats in each group. Groups B, C and D cats were vaccinated once subcutaneously with strains FCVG1, FCV431, and FCVG1 + FCV431, respectively. Each kitten received a total dose of 10(3.4) CCID50 of FCV. Control group A was not immunised. On day 31, four cats from each group were challenged oronasally with FCV220 and four cats with FCV393. Following challenge, the cats were monitored for clinical signs, viral shedding and antibody responses. FCV220 and FCV393 induced severe clinical signs in control cats typical of FCV infection. Immunisation with both strains mixed together induced higher neutralizing antibody titres against FCV220 and FCV393 strains on average. Protection was observed in all groups, however combination of the two strains resulted in a better clinical protection and reduction of virus shedding after heterologous challenge. A moderate correlation was observed between neutralizing antibody titres at the time of challenge and protection against clinical signs. These results indicated that vaccines combining antigens from different FCV strains may induce a broader heterologous protection.  相似文献   

12.
Antigenic relationship of Actinobacillus (Haemophilus) pleuropneumoniae serotype-8 isolates with other serotypes was studied, using tube agglutination, with and without 2-mercaptoethanol, indirect hemagglutination with and without 2-mercaptoethanol, ring precipitation, coagglutination, and immunodiffusion tests. Serotype-8 isolates possessed serotype-specific, group-specific common antigens cross-reactive with serotypes 3 and 6 and species-specific common antigens cross-reactive with other serotypes. Absorption studies were done to study the antigenic relationship of serotype 8 with serotypes 3 and 6. Rabbit antisera against whole-cell (WC) suspensions of reference strains of serotypes 3, 6, and 8 were used for absorption studies with WC and boiled WC suspensions of homologous and heterologous serotypes. Unabsorbed and absorbed sera were tested for antibodies against WC and boiled WC antigen preparations of serotype 8, using various serotests. Absorption studies revealed that serotype-8 strains possessed 2 main types of epitopes, one of which was serotype-specific and did not have cross-reactivity with other serotypes. The second type of epitopes was group specific and was cross-reactive with serotypes 3 and 6.  相似文献   

13.
The immunological relationship between the Ludhiana and Hissar strains, and between the Uruli-Kanchan, Bangalore and Jaipur strains of Theileria annulata was studied. Calves were immunised against the Ludhiana strain by the infection-treatment method, against the Uruli-Kanchan strain by the infection-treatment method or by untreated low-grade infection and against the Jaipur strain by untreated low-grade infection. After 45 days, groups of immune calves and susceptible controls were challenged with 10-tick equivalent stabilates. The ensuing host responses, body temperature, swelling of the regional lymph node, appearance of schizonts in the regional lymph node and piroplasms in blood and mortality, were studied. All five strains proved very virulent and produced severe disease in susceptible calves. Immunisation with the Ludhiana, Uruli-Kanchan and Jaipur strains conferred absolute protection against severe homologous challenges. Immunisation with the Ludhiana and Uruli-Kanchan strains conferred substantial protection against heterologous challenges with the Hissar strain, and the Bangalore and Jaipur strains, respectively. Immunisation with the Uruli-Kanchan strain gave less protection against heterologous challenge with the Jaipur strain and vice versa as some of the challenged calves showed slight swelling of the regional lymph node, two had fever, all exhibited a low-grade parasitaemia and four developed anaemia.  相似文献   

14.
Antibodies against Fasciola hepatica were detected in sera from experimentally infected sheep and calves. Titres in sera from field-infected sheep were related to fluke burdens. Indirect haemagglutination, counter-immunoelectrophoresis and double immunodiffusion were compared. Indirect haemagglutination and counter-immunoelectrophoresis were superior to double immunodiffusion and positive reactions in these techniques preceded the presence of parasite eggs in the faeces by at least 50 days. The relative advantages of the immunological techniques are discussed.  相似文献   

15.
The immunogenicity and cross-protection of Eimeria maxima or E. tenella in chickens against their homologous and heterologous strains were evaluated in two experiments. The immunizing strain of E. tenella protected against itself and partially against heterologous strains. The North Carolina (NC) strains of E. tenella were more virulent than the Delmarva (DMV) strains. Growth of the unimmunized groups was depressed 66% and 32% for the NC and DMV strains, respectively. Growth of the immunized-challenged groups (DMV and NC) was depressed by 13%. The DMV E. maxima strains were more virulent than the NC strains. Growth of the unimmunized challenged groups was depressed by 47% (DMV) and 13% (NC). Results demonstrated that there are antigenic variations among strains of two species of chicken coccidia.  相似文献   

16.
建立了ＡＧＩＤ用于猪伪狂犬病（Ｐｓｅｕｄｏｒａｂｉｅｓ,Ｐｒ）的诊断。对９８份被俭血清的ＡＧＩＤ结果与ＳＮ结果比较,当ＳＮ滴度大于１：８时两者的阳性检出符合率为１００％,ＳＮ滴度小于或等于１：８时,两者的阳性检出符合率为８７．５％,ＡＧＩＤ和ＳＮ总的阳性符合率为９４．４％,结果表明,ＡＧＩＤ对Ｐｒ可进行特异性诊断,流行病学调查和免疫动态监测。  相似文献   

17.
Liu S  Wang Y  Ma Y  Han Z  Zhang Q  Shao Y  Chen J  Kong X 《Avian diseases》2008,52(2):306-314
  相似文献   

18.
A highly purified pilus vaccine prepared from cells of Bacteroides nodosus strain 198 provided a high level of protection against homologous challenge and small, not statistically significant, levels of protection against challenge with 4 other strains each from different serogroups. In a second experiment, a partially purified pilus vaccine from strain 198 induced significant immunity to 1 of 4 heterologous strains which were different from those used in the first experiment. In a third experiment a strain 198 whole cell vaccine produced significant immunity against 3 of 6 heterologous strains used in the first 2 experiments. There was no obvious relationship between the colony type, degree of piliation and level of cross-protection obtained against a particular strain. The results provide further evidence that immunogens associated with, but distinct from, the pilus are involved in cross-protection and that cross-protective antigens are common to some, but not all, strains.  相似文献   

19.
The cross-reactivity of the purified polysaccharides of Actinobacillus pleuropneumoniae serotypes 1 and 9 were examined using a variety of highly sensitive assays, such as radioimmunoassay, latex agglutination, enzyme-linked immunosorbent assay (ELISA), and immunoblotting. In addition, conventional immunodiffusion was included for comparison. Latex agglutination, utilizing affinity-purified IgG to capsule, was also used to serotype whole cells. Agglutination or precipitation tests (radioimmunoassay, latex agglutination, and immunodiffusion) indicated no cross-reactivity between the capsules of serotypes 1 and 9, and no cross-reactivity between whole cells by latex agglutination. Assays that required binding of the capsule to a solid support (ELISA and immunoblotting) did demonstrate cross-reactions between serotypes 1 and 9 capsules, although reactions with the heterologous serotype were weaker than with the homologous serotype. The cross-reactivity could not be attributed solely to nonspecific factors because similar cross-reactivity did not occur with serotype 5 or 7 capsules by any assay. Reactivity of antisera with homologous or heterologous capsule was reduced, but not completely eliminated, by adsorption with washed, live bacteria of the heterologous serotype. Thus, the assay, as well as the antigen or specificity of the antibody reagent used, may influence the results of A. pleuropneumoniae serotyping or serological tests.  相似文献   

20.
OBJECTIVE: To determine the ability of antisera against cyanogen bromide-cleaved pili from 4 strains of Moraxella bovis to react with whole or nondenatured pili. SAMPLE POPULATION: Antisera to 4 strains of M. bovis produced by New Zealand White rabbits. PROCEDURE: Pili from 4 strains of M. bovis were collected and purified. Pilus proteins (pilin) were cleaved, using cyanogen bromide. Whole pilus and cyanogen bromide-cleaved pilin were injected into rabbits. Antisera were serially diluted, reacted with 4 strains of M. bovis, and examined by immunoelectron microscopy and indirect immunofluorescence. RESULTS: Antisera to whole pili aggregated and distorted pili from homologous strains, but pili from heterologous strains were unaffected. Antisera to cleaved pilin fragments resulted in partial aggregation and thickening of homologous and heterologous pili, suggestive of heterospecific antibodies. Attachment of antibodies to pili was detected by indirect immunofluorescence, indicating a strong reaction of antisera to whole pili with homologous pili. Weak cross-reactions were evident with certain heterologous strains. In contrast, antisera to cleaved pilin fragments reacted strongly with pili from homologous and heterologous strains. CONCLUSIONS AND CLINICAL RELEVANCE: We detected shared antigenic determinants on pili from various strains of M. bovis that were not immunogenic in intact pili. These sites were immunogenic after cleavage of pilus protein with cyanogen bromide, and antisera produced to protein fragments reacted with whole pili from heterologous strains of the organism. Vaccines produced from cyanogen bromide-treated pili may induce broader immunity against infectious bovine keratoconjuctivitis than that provided by currently available vaccines.  相似文献   

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