Yersinia enterocolitica associated with third trimester abortion in buffaloes

A group of buffaloes aborted at the third trimester of their gestational period. Yersinia enterocolitica was isolated from all cases. All aborted animal sera had high antibody titres against Y. enterocolitica antigen which crossreacted significantly with Brucella abortus antigen. All animals were culturally negative after intrauterine infusion of gentamycin sulphate (160 mg/day) for three consecutive days.     

Serum antibody responses of chickens following sequential inoculations with different infectious bronchitis virus serotypes

Sequential inoculations of chickens with different live infectious bronchitis virus (IBV) antigenic types had major effects on virus-neutralization (VN) and hemagglutination-inhibition (HI) serum antibody responses. Antibody production in IBV-inoculated chickens that were reinoculated 8 weeks later with heterologous virus was largely directed against the virus used for initial inoculation rather than the virus used for reinoculation. In addition, chickens inoculated sequentially with IBV produced a broadened spectrum of serum antibodies that reacted with IBV types to which the birds had never been exposed (JMK and Florida). Chickens inoculated sequentially with heterologous IBV tended to produce higher levels of cross-reacting antibody than birds given homologous virus inoculations. Levels of cross-reacting antibodies were lower than levels of specific antibodies directed against viruses that the birds had received. Limited studies indicated that birds with cross-reacting antibodies were not protected against challenge with the virus that the cross-reacting antibody was directed against. Implications of the research for interpreting serological data from commercial chicken flocks are discussed.     

The serological response of cattle immunized with Yersinia enterocolitica O:9 or O:16 to Yersinia and Brucella abortus antigens in enzyme immunoassays

Sera from calves immunized with Yersinia enterocolitica serotypes O:9 or O:16 were tested by indirect enzyme linked immunosorbent assay (ELISA) using lipopolysaccharide (LPS) preparations from Brucella abortus or Y. enterocolitica O:9 or O:16 for their antibody content of the IgG1 or IgG2 subclasses. High IgG1 responses were present with the three antigens in both groups although some individual variations between animals were noted. The IgG2 responses were modest and in some cases not above background 'noise'. Thus IgG2 antibody was not measurable in sera from serotype O:9 injected calves when using serotype O:16 LPS or in serotype O:16 injected calves when using B. abortus or serotype O:9 LPSs. A competitive ELISA using B. abortus O-polysaccharide and a monoclonal antibody to B. abortus LPS (initially designed to differentiate the antibody responses of cattle naturally infected with B. abortus from those vaccinated with strain 19) was used on sera from both groups of calves. Using this test, no antibody was detected in the group immunized with serotype O:16 and except for one animal in the serotype O:9 immunized group, only low levels of antibody were transiently in evidence. One animal in this group responded with quite high levels of competing antibody which, however, declined towards the end of the test period. The competitive ELISA may prove a useful serological tool for differentiating vaccinal and field infection titers to B. abortus and also to eliminate cross-reactions observed with Y. enterocolitica serotypes.     

IMMUNOGLOBULIN CLASSES IN SERUM ANTIBODY REACTIONS IN CATTLE FOLLOWING VACCINATION WITH BRUCELLA ABORTUS STRAIN 19 AND KILLED 45/20 VACCINES

SUMMARY A group of 4 cows was vaccinated with Brucella abortus strain 19, followed 8 weeks later by a single dose of B. abortus 45/20 vaccine. A similar group received 2 doses of B. abortus 45/20 vaccine 8 weeks apart. The antibody responses of the groups were compared by testing whole serums and separated IgM and IgG fractions by the Rose Bengal Plate (RBP) agglutination and the complement fixation tests (CFT) using rough and smooth B. abortus antigens. Animals that had received B. abortus strain 19 responded to the 45/20 vaccine with increased titres to the smooth antigen. These relevant antibodies were predominantly of the IgG class. Standard CFT and RBP test antibodies could be detected in IgM and IgG fractions after the primary inoculation with B. abortus strain 19 vaccine.     

猪伪狂犬病基因缺失活疫苗(SA215)免疫母猪后仔猪母源抗体消长规律及首免日龄

在研究猪伪狂犬病基因缺失活疫苗 (SA 2 15 )免疫接种母猪所产仔猪母源抗体消长规律 ,并绘制其消长曲线的基础上 ,确定了仔猪首免日龄。对免疫母猪所产仔猪于不同日龄进行抗体检测结果表明 ,全部仔猪均获得了高水平母源抗体 ,7日龄高达 2 8.56 ,6 0日龄降至 2 2 .56 ;随着日龄增长 ,抗体水平呈逐渐降低趋势 ,2次大幅下降出现在 14～ 2 1日龄、30～ 6 0日龄。对免疫母猪所产仔猪分别于不同日龄免疫接种 1头份剂量疫苗 (SA2 15 ) ,7d后采血进行抗体检测 ,结果表明 ,7日龄、14日龄、2 1日龄免疫接种仔猪均未引起明显抗体水平升高 ,反而较同期仔猪略有降低 ,30日龄和 6 0日龄免疫接种仔猪则出现了抗体水平的升高 ,其中以 6 0日龄仔猪升高幅度为大。结合母源抗体消长规律 ,确定猪伪狂犬病基因缺失活疫苗 (SA2 15 )免疫母猪所产仔猪的首免日龄为 30日龄     

Serological relationship between cattle exposed to Brucella abortus, Yersinia enterocolitica O:9 and Escherichia coli O157:H7

Sera from cattle naturally infected with Brucella abortus (n = 160), vaccinated with B. abortus S19 (n = 88) or immunized with Yersinia enterocolitica O:9 (n = 25) or Escherichia coli O157:H7 (n = 80) were collected. The sera were compared for antibody content to the same bacteria by indirect enzyme immunoassay (IELISA), fluorescence polarization assay (FPA) and competitive enzyme immunoassay (CELISA). Cattle sera (n = 523) collected randomly from across Canada were tested in the same tests. Sera from the B. abortus infected group reacted positively in the brucellosis IELISA (IELISA(Br)), CELISA and FPA (FPA(Br)) and the Y. enterocolitica IELISA (IELISA(Ye)) while the Y. enterocolitica FPA (FPA(Ye)) detected antibody in 93.8% and the E. coli IELISA (IELISA(Ec)) 86.9% and the E. coli FPA (FPA(Ec)) 48.1%. About 70% of the sera from B. abortus S19 vaccinated animals reacted in the three IELISAs, 45% in the CELISA, and 37.7% in the FPA(Ec), 21.6% in the FPA(Br) and 5.7% in the FPA(Ye). Sera from E. coli O:157 exposed cattle reacted mainly in the IELISA(Ec) and FPA(Ec) although surprisingly 87.5% reacted in the IELISA(Ye) and only 3.8% in the IELISA(Br). No reactions were observed with these sera in the FPA(Br) and FPA(Ye) but one serum gave a low positive reaction in the CELISA. All sera from Y. enterocolitica O:9 exposed cattle reacted in the IELISA(Br) and IELISA(Ye) and 80% in the IELISA(Ec). In the CELISA, 44% gave a positive reaction and 64% were positive in the FPA(Br), 28% in the FPA(Ye) and 12% in the FPA(Ec). Of the 523 Canadian sera, about 50% reacted in the E. coli tests with only minor reactions in the Y. enterocolitica O:9 and B. abortus assays. From the data, the cross reaction between E. coli O157:H7, Y. enterocilitica O:9 and B. abortus is dependent on the test used. Thus, extensive cross reaction was observed with the IELISA with much less reactivity in the FPA and the CELISA.     

A rapid method for detection of Yersinia enterocolitica serotype O:3 in pig feces using monoclonal antibodies.

A simple colony immunoblotting method using monoclonal antibodies (MAbs) was developed to detect Y. enterocolitica serotype O:3 in pig feces. One of the MAbs studied was able to detect single colonies of the organism in the presence of calculated 3.1 x 10(8) heterologous organisms in pig feces. The MAb was found to be specific for the lipopolysaccharide (LPS) O-antigens of Y. enterocolitica serotype O:3. No significant cross-reactivity was found against a variety of closely related serotypes and Gram-negative organisms. The MAb could also be used in a slide agglutination test and an indirect fluorescence antibody assay for rapid identification of Y. enterocolitica serotype O:3.     

Serological cross-reactivity between Brucella abortus and Yersinia enterocolitica 0:9:: IV. Evaluation of the M- and C-epitope antibody response for the specific detection of B. abortus infections

Smooth lipopolysaccharides (SLPS) from Brucella abortus contain A-epitopes against which the majority of serum antibodies are directed during infections. SLPS from Yersinia enterocolitica 0:9 possesses identical epitopes, which are the cause for serological cross-reactivity. All Brucella spp. possess M- and C-epitopes which are not present in Y. enterocolitica 0:9. In order to examine the usefulness of these M- and C-epitopes for discrimatory serological testing, a panel of sera were used in this study, comprising sera from Y. enterocolitica 0:9-infected heifers, sera from B. abortus-infected cattle of comparable strength in the serological brucellosis tests to the sera from Y. enterocolitica 0:9-infected heifers, sera from B. abortus-infected bovines with strong serological reactions and sera from animals free from B. abortus or Y. enterocolitica infections. These sera were tested in blocking ELISAs with seven M- and one C-epitope-specific monoclonal antibodies in combination with SLPS from B. melitensis M16 high in M-epitopes as antigen. Strong B. abortus sera inhibited most strongly, while negative sera showed no or little inhibition. Sera with weak or intermediate titres blocked to a lower extent. Unexpectedly, the sera from Y. enterocolitica 0:9-infected heifers showed inhibition behaviour virtually identical to the comparable sera from B. abortus infected animals. Absorbing out of the A-epitope specific serum antibodies with either Y. enterocolitica 0:9 SLPS or with Y. enterocolitica 0:9 bacteria, indicated the presence of M- or C-epitope-specific serum antibodies in some sera from B. abortus-infected cattle but not in the sera from Y. enterocolitica 0:9-infected animals. These results demonstrate that the M- or C-epitope-specific antibody response in sera from B. abortus infected cattle is only of limited value for the serological discrimination between B. abortus and Y. enterocolitica 0:9 infections.     

Immunostimulating effect of culture filtrates of Yersinia enterocolitica

Application of sterile culturing supernatant of Yersinia (Y.) enterocolitica (tested serovars were 03 and 08) caused significantly accelerated transplant rejection in mice of various inbreeding strains. Action correlated with dosage (r = -0.92). C57B16 mice were tested for their pregnancy rates in response to the same filtrate (serovar 03), with 5.5 live births per mating being recorded from 47 control matings but only 4.4 from 45 experimental matings (alpha less than 0.0025). The mean gestation period of experimental animals was extended by five percent over that of simultaneous controls (alpha = 0.25). Particular reference is made in this paper to Vesikari et al. (1987) who found Y. enterocolitica to function as interleukin-1 inductor via lipopolysaccharide. The active substance tested in this context, however, proved to be thermolabile, with 30 minutes of heating to 56 degrees C eliminating the action tested before. Y. enterocolitica infections were frequently found to coincide with rheumatoid arthritis, and evidence has been produced to the unspecific stimulating effect of Y. enterocolitica culture filtrates (testing being applied to serovar 03, biovar 4 and serovar 08, biovar 2). It is against the background of these aspects that chronic and other infections by Y. enterocolitica are considered to be of substantive relevance to the etiopathogenesis of autoimmune diseases, above all rheumatoid arthritis.     

SOME ASPECTS OF THE EPIZOOTIOLOGY OF BOVINE EPHEMERAL FEVER IN AUSTRALIA

Serum samples collected from cattle in Western Australia, Northern Territory, Queensland and New South Wales in 1966 had neutralising antibodies to ephemeral fever virus, although the last major epizootic of ephemeral fever was in 1955-56. The incidence of antibodies ranged from 1.5% in Western Australia to 29.0% in Queens- land, and 57.6% of serums assayed were of low titre (2 to 5). Antibodies were not found in serums collected from cattle in Victoria, South Australia, southern Western Australia or Norfolk Island. After the 1967-68 epizootic the pro-porton of cattle with antibody ranged from 3.1% to 47.6% in herds with antibody in Victoria to 81.8% to 91.7% in herds in Queensland, and 58.2% of serums assayed had antibody titres greater than 45. Cattle with low levels of antibody in 1966 had high levels after the 1967-68 epizootic, although it is not known what pro-portion showed clinical signs of ephemeral fever during the epizootic. Serum samples collected in 1966, and which contained low levels of antibody, were fractionated by gel filtration and the neutralising activity was confined to the 7S globulin fraction. In one cow experimentally infected with ephemeral fever virus, the neutralising activity at 15 days after inoculation was confined to the 19S globulin fraction, in both the 19S and 7S fractions at 22 days but was almost totally confined to the 7S fraction by day 36. The significance of the results is discussed, and it is suggested that ephemeral fever virus remains enzootic in areas of Australia between major epizootics, but the infecting virus may be of low pathogenicity and immunogenicity for cattle, resulting mainly in subclinical infections.     

Brucella titers in swine caused by Yersinia enterocolitica, serotype 0:9

Antibody to Brucella abortus developed in two thirds of all gilts kept on a pig breeding station. Systematic tests taken for the purpose of detecting clinical symptoms and of isolating Brucella were negative. however, Yersinia (Y.) enterocolitica, Serotype 0:9, was cultured from rectal swab samples which had been obtained from 31 to 78 gilts. The clinical, bacteriological, and serological tests gave rise to the assumption that the Brucella titres have been caused by Yersinia enterocolitica infection. Such conclusion, however, could be drawn only as a result of a complex investigation. Detection of Yersinia enterocolitica alone is not sufficient a proof by which to rule out the possibility of concomitant Brucella infection. The question is discussed to what extent swine may be considered to be a potential source of infection of man.     

流产布氏杆菌S19突变株构建及在小鼠感染模型中的免疫保护评估

通过构建标记疫苗株来解决流产布氏杆菌(B.abortus)鉴别诊断方面的缺陷,本研究以bp26基因作为重组靶住点,S19为亲本,利用bp26基因ORF外侧序列作为同源重组序列,卡那霉素抗性基因(Kanr)为抗性筛选标记,通过双交叉重组筛选获得bp26基因缺失突变的重组S19株,命名为S19-△26.小鼠感染结果表明,突变株S19-△26的残留毒力与亲本株S19相比较没有发生明显改变,康复时间约为15周,突变株S19-△26、亲本株S19和B.abortus强毒株S544接种小鼠后的第3周能检测出"O"抗原的特异性抗体,而第6周开始S19和S544接种小鼠BP26特异性抗体明显升高,S19-△26接种的小鼠一直没检测到BP26特异性抗体.小鼠免疫保护试验显示,脾脏分离CFU数比空白对照要低310g10,S544攻击后脾脏细菌分离数表明突变株具有与亲本疫苗株免疫保护性无明显差异.结果表明,S19-△26免疫能够通过血清学方法与野生型B.abortus感染后的免疫反应相区别,具备作为标记疫苗的潜力.     

Escherichia coli Agglutinins in Cow Serum, Colostrum and the Nursing Calf

Immunochemical properties of Escherichia coli O antibodies present in bovine serum and colostrum were investigated. Dam and calf serum samples plus colostral whey samples were fractionated by gel filtration, and the 7S and 19S fractions isolated. Antibody activity against the O antigens of four recognized E. coli bovine pathogens was determined by the indirect hemagglutination test on the whole serum and colostral whey samples and the 7S and 19S fractions thereof. Mercaptoethanol reduction was used to chemically study the immunochemistry of the E. coli O antibodies.

The E. coli O antibodies in dam serum were entirely 19S macroglobulins and appeared to be IgM immunoglobulins. The antibodies in colostrum and calf serum were both 7S and 19S globulins. Reasons for believing these 7S antibodies may be IgG, and the 19S antibodies IgA, immunoglobulins are presented.

     

The pathogenicity of Yersinia enterocolitica for piglets.

The pathogenicity of Yersinia enterocolitica, a bacterium that has been isolated frequently from healthy swine, was studied in piglets by oral challenge of two litters, one derived by cesarean section and deprived of colostrum, and the other delivered at full-term. Eight cesarean-derived piglets were divided into groups of two and challenged with four serotypes of Y. enterocolitica (O:8, O:21, O:3, O:13). Two deaths occurred and two piglets were killed because of severe illness before termination of the experiment eight days after challenge. Surviving piglets showed no clinical signs of illness. Rectal cultures were consistently positive and all cesarean-derived piglets were colonized in the small intestine and throat at necropsy. Full-term piglets were allowed access for 36 hours to sow colostrum containing low levels of antibody against the challenge strains. Six full-term piglets challenged with three serotypes of Y. enterocolitica (O:8, O:21, O:13) survived for 15 days without any signs of illness. These piglets had fewer positive rectal cultures and showed less extensive colonization of internal organs at necropsy than did cesarean-derived piglets. It is uncertain whether this increased resistance to infection with Y. enterocolitica resulted from colostrum-derived antibody, intestinal colonization with other bacteria, or an improved physical condition which accompanied full-term development. Nevertheless, the results of this challenge experiment suggest that piglets are capable of restricting colonization by Y. enterocolitica to the throat and intestinal tract without development of serious illness.     

Antibody response and duration of latent infection in sheep following experimental infection with Babesia ovis

Babesia ovis isolated in Extremadura (Spain) was the subject of a serological study in experimentally inoculated sheep. The first antibody titres, determined by the indirect fluorescent antibody (IFA) test, were observed 7-8 days post infection (p.i.) in all animals except the splenectomized group, in which the only animal that survived showed antibody response 10 days p.i. A faster response following challenge was observed in sheep which were seropositive before inoculation, which suggests the existence of an antigen memory. The highest titres were reached 16-25 days p.i., and subsequently began to fall, reaching minima at the end of the experimental period (330 days p.i.). The chronic carrier state in experimental B. ovis infection had a duration of at least 2 years. Passive transmission of antibodies from experimentally infected mothers to newborn lambs was also detected. Antibody levels were observed for a period not longer than 2 months after birth.     

Variations in immunoglobulin isotype produced during the antibody response to Brucella abortus and Staphylococcus aureus vaccines in sheep

Experiments in sheep were carried out to examine factors modifying the immunoglobulin (Ig) isotype of the antibody response to Brucella abortus. Live B abortus (S19) stimulated higher titres of agglutinating antibody and IgG1 and IgG2 antibody than did killed B abortus. Live B abortus stimulated a more protracted synthesis of IgG2 antibody during the primary and secondary responses than did the killed S19 vaccine. In a second experiment, the capacity of live and killed Staphylococcus aureus to modify the antibody response to killed B abortus was examined. Both live and killed S aureus enhanced production of anti-brucella antibodies; this response was attributed to the adjuvant properties of S aureus. Killed S aureus enhanced production of anti-brucella antibody to a greater extent than live S aureus. Live S aureus did not preferentially enhance production of IgG2 anti-brucella antibody. The results suggested that the enhanced production of IgG2 antibody induced by live vaccines does not depend solely on a pyogenic lesion at the vaccination site.     

Studies on the relationship between Yersinia enterocolitica IX and Brucella abortus agglutinins in naturally infected animals

Attempts were made to define the Brucella abortus and Yersinia enterocolitica IX infection status of animal populations by means of selected agglutination tests. The Brucella abortus O, the Yersinia enterocolitica IX OH and the Y enterocolitica IX H agglutinin titres were measured in a large number of cattle, goat and pig sera In the goats and, to a much lesser extent, the pigs, the relationships between these titres suggested that Yersinia infection was common. In contrast, the results from the cattle sera were complex and tended to indicate the presence of both Yersinia infection and brucellosis.     

Brucella clearance as a sensitive method for the detection of cross reactions of Brucella abortus with Yersinia enterocolitica 03, 06, 09 and Salmonella urbana and Salmonella abony

Determination of the Brucella clearance rate has proved to enable assessment of Brucella immune reaction in rat, even after vaccination with Yersiniae and Salmonellae. Vaccination with Yersinia (Y.) enterocolitica O6 and O9 produced 95 per cent of "high responders", whereas 65 per cent of "high responders" and 25 per cent of "non-responders" were recorded in the wake of O3. Salmonella (S.) urbana vaccination gave 50 per cent of "high responders" and 27 per cent of "non-responders", while 100 per cent "non-responders" resulted from S. dublin. Vaccination, using Brucella abortus Buck 19, gave 100 per cent "high responders". The differentiated nature of immune reactions to Y. enterocolitica O3, S. urbana, and S. abony has been attributed to an individual genetic capability of reaction to the cross-reactive antigen.     

抗犬瘟热病毒重组核衣壳蛋白单克隆抗体的制备及鉴定

以纯化的重组犬瘟热病毒(CDV)N蛋白免疫BALB/c小鼠,应用常规杂交瘤技术获得两株能稳定分泌特异性单克隆抗体的杂交瘤细胞系,分别命名为A_4C_6C_(12)和A_5B_8H_7。间接ELISA检测腹水效价分别为1:10~6、1:10~5;亚类鉴定结果分别为IgG2a、IgG2b,轻链均为κ型;Western blot和ELISA分析结果显示2株单克隆抗体均能与重组N蛋白和CDV发生反应,而与犬细小病毒及犬腺病毒等无交叉反应;ELISA叠加试验的增值结果表明两株单克隆抗体识别的抗原位点不同。特异性抗CDV-rN的单克隆抗体的获得,为进一步用于临床诊断研究奠定了基础。     

Antibody response to experimental Salmonella typhimurium infection in chickens measured by ELISA

An indirect ELISA has been developed to detect Salmonella typhimurium antibodies in chicken sera, using whole bacterial cell protein, flagellar protein or lipopolysaccharide as antigens. In experimental infections high concentrations of S typhimurium-specific IgG persisted after the faecal excretion of S typhimurium had ceased, whereas the specific IgM response was transitory. Some uninfected chickens placed in contact with experimentally infected birds developed high IgG titres in the absence of detectable faecal excretion. Other S typhimurium strains, which varied in their invasive abilities, also induced high titres of IgG. The ELISA allowed chickens infected experimentally with S typhimurium to be differentiated from chickens infected with 10 other serotypes, including S enteritidis. The use of whole blood in place of serum in the ELISA reduced the titres slightly. The storage of serum dried on to filter paper strips for four weeks produced little change in ELISA antibody titre, and the treatment of such strips with phenol or chloroform vapour had little or no effect on the antibody titre.