Immunoglobulins in cattle vaccinated with leptospiral bacterins.

The growth-inhibition test was used to detect specific antibodies against Leptospira interrogans serotype hardjo in isolated immunoglobulin (IgG and IgM) fractions of serums from cattle vaccinated with leptospiral bacterins. The growth-inhibiting antibodies were detected mainly in the IgG class. Agglutinated clumps also occurred with the IgM fraction. The serums collected from cattle 4 months after vaccination were negative in the microscopic agglutination test.     

Specific antibodies to Besnoitia besnoiti precipitated from serum of cattle by live parasites and by soluble antigen

Specific precipitable antibodies of both IgG and IgM classes were detected in sera of cattle naturally infected with B. besnoiti. The amount of specific antibodies of the IgG class precipitated by soluble antigen was in the range of 17-50 micrograms/ml serum while that of the IgM class ranged between 5 and 24 micrograms/ml serum. Specific antibodies precipitated by live B. besnoiti parasites were in amounts of 10 to 22 micrograms/ml serum for IgG and 4 to 26 micrograms/ml serum for IgM. Different ratios of IgG/IgM were obtained by the two methods of precipitation. This might indicate that antibodies to B. besnoiti of the IgM class can be precipitated and detected in sera of naturally infected cattle in similar amounts either by live parasites or by solubilized antigen, whereas antibodies of the IgG class can be preferentially detected when solubilized antigen is used for precipitation.     

An abortion storm in cattle associated with neosporosis in Taiwan

An abortion storm associated with acute neosporosis involving 18 cattle was observed in a dairy farm in Taiwan. Aborted fetus age ranged from 3 to 8 months. Of the 38 cattle in that farm examined during the abortion storm, 52.6% (20/38), 13.2% (5/38) and 10.5% (4/38) contained both IgG and IgM, only IgG and only IgM antibodies to Neospora caninum, respectively. No antibody to N. caninum was detected prior to the abortion storm. Follow-up study conducted a year later showed that 23 out of 28 cattle had sero-converted. Since some cattle were positive to either only IgG or IgM, we suggest that both IgG and IgM should be tested for diagnosing neosporosis. Neosporosis surveillance of naive cattle herd is recommended.     

Enzyme-linked immunosorbent assay for detection of bovine immunoglobulin G1 antibody to a protoplasmic antigen of Mycobacterium paratuberculosis

An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of antibodies to Mycobacterium paratuberculosis in the sera of cattle. This assay was designed to minimize the nonspecific ELISA reactions caused by immunoglobulin (Ig)M by measuring only IgG1 antibodies against a protoplasmic antigen from the organism. The ELISA detected IgG1 antibodies in the sera of 58% of cattle with positive fecal cultures for M paratuberculosis compared with detection of 45% of culture-positive animals with an immunodiffusion test. In addition to its sensitivity, the ELISA apparently is highly specific because only 4% of the sera from fecal culture-negative animals gave a false-positive result.     

Trypanosome non-specific IgM antibodies detected in serum of Trypanosoma congolense-infected cattle are polyreactive.

Serum Ig from Trypanosoma congolense-infected cattle were affinity-purified using immobilised trypanosome or non-trypanosome antigens (beta-galactosidase, cytochrome C and ferritin). The bound and unbound IgG and IgM fractions were collected and tested in ELISA for reactivity to each antigen. The results indicated that the presence of reactivity to non-parasite antigens in serum of infected cattle is due to polyreactive IgM antibodies. However, the IgG fraction only bound to trypanosome antigens and was only present in post-infection sera, indicating that it was induced by the infecting trypanosomes. Since the polyreactive IgM antibodies were also present in pre-infection sera, it is probable that they were natural antibodies that were not induced but only amplified by the trypanosome infection.     

ELISAs based on rNcGRA7 and rNcSAG1 antigens as an indicator of Neospora caninum activation

Bovine abortion caused by the Apicomplexa parasite Neospora caninum is a major economical problem in the livestock industry worldwide. However, the relationship between N. caninum infection and abortion is still unknown. Our study aimed to elucidate the relationship between parasite-specific antibody responses, parasite stages and abortion. In experimentally infected cattle, anti-NcGRA7 IgG1 antibody was predominantly detected during the acute infection stage, while the production of anti-NcSAG1 IgG1 antibody was observed during both acute and chronic stages. Furthermore, levels of anti-NcGRA7 IgG2 antibody were lower than those of anti-NcSAG1 IgG2 antibody. When tested on cattle with Neospora-associated abortion, positive rates of the anti-NcGRA7 IgG2 antibody were significantly lower than those of the anti-NcSAG1 antibody, although there was no difference in IgG1 antibody-positive rates between the two antigens. In addition, anti-NcGRA7 IgG2 antibodies were not detected in cattle for more than 30days after abortion. Our results suggested that anti-NcGRA7 and anti-NcSAG1 antibodies are suitable indicators for the activation stage of N. caninum infection and broad detection of the infection, respectively. In conclusion, the use of recombinant NcGRA7 and NcSAG1-based ELISAs will be useful for evaluating the abortion risk associated with N. caninum infection.     

Molecular specificity of the antibody responses of cattle naturally and experimentally infected with cytopathic and noncytopathic bovine viral diarrhea virus biotypes

The specificity of the humoral IgG response of cattle naturally or experimentally infected with bovine viral diarrhea virus (BVDV) was studied by radioimmunoprecipitation. Serum samples were tested against radiolabeled lysates of cells infected with cytopathic and noncytopathic biotypes of BVDV. A biotype-specific serologic marker was not detected. The specificity of the IgG induced in cows naturally or experimentally infected with either BVDV biotype was essentially the same. A strong IgG response to the 2 glycoproteins (56 to 58 kilodaltons, [kD] and 48 kD) of both biotypes and to the major polypeptides was induced in infected cells: 118 kD and 80 kD by cytopathic BVDV and only 118 kD by noncytopathic BVDV. The most consistent difference among cattle was the presence of IgG specific for the 37-kD polypeptide. Sequential serum sample collection after spontaneous and induced infections with either BVDV biotype did not indicate specific IgG markers for determining infection history. Sera from cattle with a confirmed diagnosis of mucosal disease and lacking neutralizing antibodies to BVDV usually lacked (greater than 80%) nonneutralizing BVDV-specific IgG. One animal had substantial amounts of IgG to the 80-kD polypeptide. Other cattle had less readily detectable amounts of IgG specific for 80-kD or 37-kD viral polypeptides.     

Evaluation of the enzyme-linked immunosorbent assay in the detection of cattle infected with Brucella abortus

One group of 51 cattle was vaccinated with B. abortus S19 (S19) and a further 51 cattle were vaccinated with B. abortus S45/20 (S45/20). Forty-eight cattle (24 from each group) and a control group of 12 cattle were subsequently challenged with B. abortus S544. The enzyme-linked immunosorbent assay (ELISA) was used to detect specific IgG and IgM antibodies in these groups. All cattle vaccinated with S19 had high levels of IgG and IgM, but the S45/20 vaccine produced detectable antibody in only a few cattle. In those cattle where the challenge induced infection, the mean levels of IgG and IgM were much higher than those of the uninfected cattle in the same groups. When the isolation of B. abortus was compared at slaughter with the serological results, the ELISA, when used to detect specific IgG, was more sensitive but less specific than the serum agglutination test, complement fixation test and indirect haemolysis test, and more sensitive and more specific than the Rose Bengal test.     

Report of a serological study of Coxiella burnetii in domestic animals in Albania

The prevalence of Coxiella burnetii antibodies in domestic ruminants in Albania has been investigated. A total of 1656 serum samples taken from sheep, goats, and cattle housed on farms located in 20 different districts were tested by ELISA for the presence of specific antibodies to C. burnetii phase I and II antigens. Specific IgG antibodies were detected in 9.1% of the animals from both lowland and mountainous areas. In total, a slightly higher percentage of antibodies was detected in sheep and goats (9.8%) than in cattle (7.9%).     

An enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to bovine viral diarrhoea virus (BVDV) in cattle sera

A microtitre ELISA has been established for the quantitation of antibodies to bovine viral diarrhoea virus (BVDV). Single dilutions of sera were assayed and units of antibody were calculated from a standard curve. In order to detect the maximum number of responding animals both IgG1 and IgG2 antibody should be assayed, although detection of IgG1 alone was nearly as effective. The ELISA was as sensitive as the virus neutralization test for detection of antibody; comparison of an ELISA that detected IgG1 plus IgG2 antibody to BVDV with the virus neutralization test gave a correlation coefficient (r) of 0.89 (P less than 0.001 for 95 compared sera). Although similar amounts of IgG1 and IgG2 antibodies were present in sera from both experimentally- and naturally-infected cattle, antibody to BVDV in colostrum and in the sera from young calves was predominantly IgG1. The number of adult cows with antibody was 40 out of 41 while 36 of 44 calves reared in a beef unit were found to have produced antibody by the time they were 31.5 weeks old, an indication of the high prevalence of BVDV in the cattle population.     

Antibodies to prion and Acinetobacter peptide sequences in bovine spongiform encephalopathy

An amino acid sequence homology has been identified between the bovine prion sequence (RPVDQ) and the Acinetobacter calcoaceticus enzyme, uridine-diphosphate-N-acetyl glucosamine-1-carboxy-vinyl-transferase which also contains (RPVDQ). Class-specific IgA, IgG and IgM antibodies against synthetic peptides containing the structurally related sequences present in bovine prion and A. calcoaceticus were measured in 189 bovine spongiform encephalopathy (BSE) positive cattle, 127 BSE negative cattle and 87 healthy control animals using an ELISA technique. Class-specific IgA, IgG and IgM antibodies against the structurally related synthetic peptides were significantly elevated in BSE positive cattle when compared to BSE negative cattle (P < 0.001) and healthy control animals (P < 0.001). These autoantibodies may have a role in the pathogenesis of BSE.     

Analysis of the IgG antibody response against Paramphistomidae trematoda in naturally infected cattle. Application to serological surveys

The IgG antibody response to Calicophoron daubneyi (Digenea: Paramphistomidae) excretory/secretory antigens was evaluated in naturally infected cattle from Lugo (Galicia, NW Spain) by using an ELISA procedure. Two studies were conducted, first a survey in 524 cattle separated into three groups according to age, G-1 (0–2 years old), G-2 (3–5 years old) and G-3 (>6 years old). In the second study, three groups of cattle were employed: G-I, naturally infected; G-T, naturally infected and treated with oxyclozanide plus levamisole (Nilzan Plus^®); G-C, cattle maintained in a farm where C. daubneyi has never diagnosed. Variations on egg-output and haematic parameters (erythrocytes, haematocrite, leukocytes and lymphocytes) were also analyzed.

The ELISA procedure showed that 61.2% of the cattle in the first study had been exposed to the trematode, but only 10.1% passed eggs in the feces. Age-association with egg-output was shown but not with the IgG values. In the second experiment, the administration of the anthelmintic reduced significantly the IgG kinetic levels and the C. daubneyi-egg-output was suppressed during 12 weeks in the G-T group. The values of red cells, haematocrite, leukocytes and lymphocytes increased significantly in the treated cattle 5 weeks after chemotherapy; however, new reduction after week 5 was recorded, as results of the challenge of these cattle.

This is the first investigation in which evaluation of the IgG humoral response against C. daubneyi in cattle has been carried out. We proved that a notable IgG response in naturally infected cattle is induced, and can be detected by using an ELISA procedure. The IgG antibodies did not increase after challenge infection. Our results proved an important percentage of cattle were exposed to this trematode in the area of study and suitable measures for preventing this relationship must be considered.     

In vitro production of antibodies to bovine virus diarrhoea virus by peripheral blood mononuclear cells from cattle immunized by infection

A method for in vitro production of antibodies to bovine virus diarrhoea virus (BVDV) by peripheral blood mononuclear cells (PBMC) was developed. The PBMC were cultured in microtitre plates coated with detergent-solubilized BVDV and the supernatants were tested in an enzyme-linked immunosorbent assay which detects IgG antibodies to BVDV. Following incubation of PBMC with an optimal concentration of pokeweed mitogen for 5 days, antibodies to BVDV were detected in culture supernatants of PBMC from immune cattle, but not in supernatants of PBMC from seronegative cattle, from persistently BVDV-infected cattle or from a 5-day-old calf that received BVDV antibodies via colostrum. This antibody-production assay may therefore be used as a tool to discriminate between passively acquired antibodies and those actively induced.     

Brucella abortus-specific immunoglobulin in isotypes in serum and vaginal mucus from cattle vaccinated with strain 19 and challenge exposed with virulent strain 2308

The immunoglobulins (IgG1, IgG2, IgM, and IgA) of the Brucella-specific antibody response of 69 crossbred beef heifers were studied after Brucella abortus strain 19 vaccination and strain 2308 challenge exposure. The immunoglobulin isotype responses in serum and vaginal mucus were measured by use of fluorescent immunoassay. Serum antibody responses were detected also by 3 standard serologic tests (complement fixation [CF], Rivanol precipitation, and the CARD test] and 2 primary bindings assays that detect IgG antibodies. One month after vaccination, mean antibody titers for all immunoglobulin isotypes were higher for vaccinated cattle (n = 46) than for nonvaccinated controls (n = 23). After vaccination, IgA antibody responses in vaccinated cattle were only 2-fold higher than those for controls, whereas IgG1, IgG2, and IgM antibody responses were 3- to 90-fold greater than those for controls. Measurement of IgA antibody responses classified 21 of 39 vaccinates as seropositive after vaccination, whereas the other isotypes classified 28 or 34 cattle as seropositive. Three months after challenge exposure, the mean antibody responses for each isotype were higher in cattle that aborted or were culture positive than in cattle that did not abort and were culture negative. Although IgG1, IgG2, and IgM antibody titers were each of benefit in identifying B abortus-infected cattle, it did not appear that the magnitude of the antibody responses provided sufficient discrimination between S19-vaccinated cattle and S2308 challenge-exposed cattle. Serum IgA antibody responses were 10-fold higher after challenge exposure than after vaccination and may be a response to mucosal infection with the virulent organism.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immunoglobulin M-specific enzyme-linked immunosorbent assay for serodiagnosis of bovine respiratory syncytial virus infections

An antibody-capture enzyme-linked immunosorbent assay (ELISA) for detection of immunoglobulin (Ig) M antibodies to bovine respiratory syncytial virus (BRSV) in cattle was developed. Monoclonal antibody to bovine IgM was used as the catching antibody. The IgM-ELISA was used, as well as a BRSV-specific IgG ELISA to determine the kinetics of IgM and IgG antibody responses to BRSV infections in cattle. High IgM and IgG antibody titers developed after naturally occurring or induced BRSV infection of calves (6 to 7 months old). Induced infection resulted in an IgM response that was first detectable at postinoculation day (PID) 11 reached a maximum at PID 13, and became undetectable again about PID 28. An IgG response also was detected by PID 11. However, a maximum response was not reached before PID 23, and titers remained high (until PID 80). In naturally occurring infection, IgM and IgG responses in calves were observed in the acute phase of epizootics of respiratory tract disease. Patterns of IgM and IgG response curves were similar to those observed in experimentally infected calves. The involvement of BRSV in an epizootic of respiratory tract disease in 8 calves (2 to 3 weeks old) was demonstrated by the detection of BRSV in several lung lavage samples. All calves had existing IgG antibodies to BRSV which were interpreted to be maternally derived. None of the calves responded with an increase in IgG antibody titer. However, a weak but distinct BRSV IgM antibody response occurred in 6 calves.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of the agar gel immunodiffusion test and ELISA in the detection of bovine leukosis virus antibody in cattle persistently infected with bovine virus diarrhoea virus

When six cattle persistently infected with bovine virus diarrhoea virus (BVDV) were inoculated with lymphocytes infected with bovine leukosis virus (BLV), a depressed antibody response to BLV was observed by ELISA which was due to a decrease in IgG1 synthesis. The ELISA was more sensitive and more reliable than the agar gel immunodiffusion (AGID) test in detecting BLV infection in cattle persistently infected with BVDV. Decreased antibody responses were manifested in the AGID test by negative, inconclusive or weakly positive reactions: only two of the six cattle developed antibodies that generated positive AGID reactions.     

Antibody response in bovine pharyngeal fluid following foot-and-mouth disease vaccination and, or, exposure to live virus

Samples of pharyngeal fluid and serum were collected from cattle after exposure to live foot-and-mouth disease (FMD) virus (with or without prior vaccination) or after subcutaneous vaccination with inactivated virus. The pharyngeal fluid samples were examined for FMD neutralising activity and specific anti-FMD IgG, IgM and IgA antibodies. The neutralising activity of the serum was also monitored. A peak of neutralising activity which occurred in the pharyngeal fluid of unvaccinated cattle seven days after virus exposure corresponded to a rise in specific IgM and IgA antibodies. This peak appeared to be due to serum and tissue fluid escaping from the damaged mucosa during the acute inflammatory phase of infection. At later stages (20 to 60 days after virus exposure) the pharyngeal fluid neutralising activity corresponded to a rise in specific IgA antibodies, suggesting that active local antibody production was taking place. The pharyngeal fluid neutralising activity detected after revaccination with oil emulsion or aqueous vaccines, without exposure to live virus, corresponded to a rise in specific IgG and IgM antibody levels and this may have been due to serum transudation.     

Preliminary evidence for a diagnostic immunoglobulin G1 antibody response among culture-positive cows vaccinated with Brucella abortus strain 19 and challenge exposed with strain 2308

The sera of cows inoculated with Brucella abortus have a characteristically high titer of immunoglobulin (Ig) G1 antibodies to a soluble brucella antigen compared with sera of noninoculated vaccinated cattle. Concentrations of antigen-specific IgG1 were greater than 10-fold higher than those for IgG2, even though total IgG2 concentrations were higher than total IgG1 concentrations. Increases in IgG1 antibodies to Brucella abortus soluble antigen were detected shortly after vaccination in those cows from which strain 19 was isolated and by 28 weeks in cows from which strain 2308 was isolated. Increases in specific antibodies were not paralleled by increases in either total IgG1 or total IgG2 concentrations. Rather, there was a 15-fold to greater than 200-fold increase in specific activity, with up to 16% of the IgG1 specific for the brucella antigen used in the assay. Thus, measurement of changes in total IgG1 concentrations is not a reliable method to identify brucellosis-associated anti-Brucella abortus soluble antigen activity. Only one cow in a panel of 10 selected for detailed study showed a false-positive IgG1 titer, whereas some serologic assays showed as many as 4 or 5 false-positives. Results of the complement-fixation test, among the battery of serologic tests used for detection of brucellosis, best agreed with the occurrence of increased IgG1 antibody levels.     

Serological responses of cattle after treatment and during natural re-infection with Fasciola hepatica, as measured with a dot-ELISA system

The dot-ELISA reaction was used to study the dynamics of IgG titers in cattle naturally infected with Fasciola hepatica after anthelmintic treatment and during reinfection. Excretion/secretion products (ES) of the parasite were used as antigens for the dot-ELISA. IgG antibodies were no longer detectable by dot-ELISA, 4-6 months after nine animals received the first of three weekly doses of triclabendazole (15 mg kg(-1)) and were then maintained on a pasture free of F. hepatica metacercariae. Six fluke-free cattle began shedding F. hepatica eggs 3-6 months after grazing a pasture contaminated with metacercariae of the parasite. A detectable increase in dot-ELISA IgG antibody levels was observed 2-4 weeks after natural reinfection by grazing a similar pasture contaminated with F. hepatica metacercariae. The usefulness of the dot-ELISA system to diagnose chronic infection by serology is complicated by previous treatment against the parasite. It is concluded that the ES antigens can be useful to detect early infection of cattle with F. hepatica in a dot-ELISA system