[Reiter protein complement-fixation (RPCF) test for diagnosis of syphilis: clinical and serologic observations].
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Complement Fixation Tests↗
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Serological detection of equid herpesvirus 1 infections of the respiratory tract.
An investigation was made of 3 serological tests (virus neutralization, complement fixation and indirect immunofluorescence), which are applicable to epidemiological studies of infections by Equid herpesvirus 1 (EHV-1). Sera from gnotobiotic foals inoculated intranasally with various strains of EHV-1 were unable in some cases to neutralize heterologous strains and these results were not consistent with the existence of clearly-defined subtypes of EHV-1, as previously proposed. The cross-reactions in complement-fixation tests paralleled those with neutralization but immunofluorescence tests were found to be both more sensitive and more broadly reactive than the other two. Complement-fixing antibodies declined more rapidly following experimental infection than did those measured by neutralization or immunofluorescence. The results are discussed in relation to the diagnosis of EHV-1 infection and the significance they may have for the epidemiology of this disease.
Animals↗
Evaluation of new and currently used diagnostic procedures for bovine brucellosis.
The indirect haemolysis test (IHLT) and the rough antigen complement-fixation test (RCFT) were compared with several conventional tests using serum samples from 9 cows known to be infected with Brucella abortus. In 7 cows all the tests except the RCFT (which was developed to detect antibodies resulting from 45/20 vaccination) became positive and remained so until the cows were autopsied 6 months after infection. In the other 2 cows the Rose Bengal test was occasionally negative and the titre of the serum agglutination test only reached 100 iu briefly. The routine complement-fixation test, the IHLT and the anti-bovine globulin test reached diagnostic levels at most of the weekly test intervals but occasional low titres occurred in them all. Only very low or negative titres were detected by the RCFT.
Animals↗
Antibodies in calves on feed supplemented with chlortetracycline after vaccination with Brucella abortus strain 19.
Twenty dairy heifers each consumed 350 mg of chlortetracycline/day in their feed. Four tests were performed on serum specimens from these and 20 control calves after vaccination with Brucella abortus strain 19. The numbers of positive test results on the card test and mean titers on the tube and rivanol agglutination and complement-fixation tests were compared in the 2 groups. Using the rivanol and complement-fixation tests, there were differences in the mean titers at weeks 5 and 6 after vaccination, but by week 10, differences were not found. The results suggest that addition of low concentration of chlortetracycline in feeds have minimal effects on postvaccinal serologic reactions determined after strain-19 inoculation.
Agglutination Tests↗
[Comparative diagnostic value of methods for detecting dysentery antigens in substrates of the patient's body].
The comparative evaluation of different immunological methods, such as the enzyme immunoassay, the aggregate hemagglutination test and the complement fixation test, used for the detection of specific Shigella antigens in biological body substrates obtained from 287 patients with acute dysentery caused by S. sonnei, S. flexneri and S. newcastle has been carried out. The enzyme immunoassay and the aggregate hemagglutination test most effective (97.5 +/- 0.5 and 92.4 +/- 0.9, respectively), the object of study being the patients' blood taken at the early stages of the disease. The diagnostic specificity of these methods has proved to be 98.7 +/- 6.7 and 95.2 +/- 1.4, respectively.
Agglutination Tests↗
[Immunological diagnosis of filariosis in persons returning from tropical countries and in European and indigenous inhabitants of endemic areas (author's transl)].
Serum samples from persons who lived in areas where onchocerciasis occurred or who had filariasis were examined with the complement fixation test and the indirect hemagglutination test for the presence of antibodies against crude extracts from Dirofilaria immitis, Onchocerca volvulus, Dipetalonema viteae, and Ascaris suum. The results could be interpreted as follows: 1. The indirect hemagglutination test was more sensitive than the complement fixation test for the demonstration of antibodies in sera from European and indigenous inhabitants of endemic areas. 2. There were no differences between the responses to the four crude worm extracts among the groups of 21 patients with Loa loa, 12 patients with Onchocerca volvulus, 11 patients with Dipetalonema perstans, and 22 patients with clinical filariasis in whom no microfilaria had been found. It was concluded that the examination with crude extracts cannot give any information about the antigens that had caused the stimulation of antibodies.
Adolescent↗
Serological response of cattle after vaccination and challenge with Brucella abortus.
New and currently used serological procedures were evaluated using sera from cattle that were challenged with B. abortus S544 (S544) after vaccination with either B. abortus S19 (S19) or B. abortus 45/20 (S45/20) as calves or adults. In animals vaccinated with S19, titres to the indirect haemolysis test (IHLT) rose more slowly, declined more rapidly and involved fewer animals than did titres to the complement fixation test (CFT). In animals vaccinated with S45/20 the rough antigen complement fixation test (RCFT) showed persistent titres. At slaughter the IHLT and CFT were found to be more specific and more sensitive than the Rose Bengal Plate Test (RBPT) and Serum Agglutination Test (SAT) in the detection of cattle infected with B. abortus.
Agglutination Tests↗
The role of carrageenan in complement activation.
A study has been made of the nature of the interaction between complement and carrageenan, which has been widely reported to inhibit haemolytic complement activity both in vivo and in vitro. Using modified haemolytic complement-fixation tests, the degree of complement consumption by various forms of carrageenan was measured in whole human and rat sera. The median effective concentrations of the carrageenans studied were found to lie in the range 3-300 micrograms/ml for the classical pathway and 500-7800 micrograms/ml for the alternative pathway and were unrelated to sulphate content, as determined by energy dispersive X-ray analysis. It was also found that carrageenan-coated sheep erythrocytes were lysed by complement. This activity was suppressed by ethylene glycol-bis-(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, which inhibits the classical, but not the alternative pathway, providing conclusive evidence that carrageenan preferentially activates the classical pathway. This finding may help in elucidating the inflammatory reaction induced by carrageenan.
Animals↗
Comparison of the Seradyn Color Vue passive agglutination test and complement fixation for detection of Mycoplasma pneumoniae antibodies.
We compared traditional complement fixation (CF) with a new passive agglutination method, the Seradyn Color Vue (SCV) test (Seradyn, Indianapolis, Ind.), for detection of Mycoplasma pneumoniae antibodies in 170 stored serum samples. The SCV test was 90% sensitive in identifying as positive 27 of 30 CF high-titer (> or = 1:64) serum samples and 100% specific in identifying as negative 134 of 134 CF low-titer (< or = 1:32) or negative (< 1:8) serum samples. The SCV test was technically undemanding, and it required no expensive equipment.
Agglutination Tests↗
[Cerebrospinal fluid in cysticercosis of the brain].
Cerebrospinal fluid (CSF) changes in brain cysticercosis have long been known. Its characteristic features are a mild or moderate pleocytosis with eosinophils, a slight or moderate protein increase with an elevated gammaglobulin concentration, and a positive complement fixation test. Unfortunately all these abnormalities are not always present together and difficulties may be encountered in the diagnosis. This paper presents a study based on the experience acquired in the CSF Laboratory of the Neurological Department of Escola Paulista de Medicina (São Paulo, Brasil) after 35 years' work, and 120.000 CSF specimens examined. The material consists of 147 cases of brain cysticercosis confirmed by necropsy, surgery, subcutaneous or intraocular cysticercus, x ray of the skull, and of 509 clinical observation with suggestive CSF changes. It is the purpose of this paper to appreciate the importance of each of the CSF tests and to observe the CSF abnormalities during the course of this disease. The results of the study of the 79 cases varified by necropsy or surgery showed that the characteristic CSF changes that make the diagnosis of brain cysticercosis were observed in 54 percent of the cases. The eosinophils were present in 82 percent, protein changes in 78 percent, complement fixation test in 70 per cent, hypertension in 55 per cent, and decreased sugar content in 27 per cent of the cases. In two cases the CSF was normal. As the eosinophils and the protein abnormalities may be seen in several other diseases, the complement fixation test for cysticercus should be regarded as the most important CSF test in the diagnosis of brain cysticercosis. The successive CSF specimens withdrawn of 40 patients during the course of this disease have shown that the abnormalities went on for 4 to 18 years observation, suggesting that the parasites were alive. On the contrary, in 11 other cases it was varified the final CSF normalization after 5 to 14 years, suggesting that the parasites were dead. The CSF was normal in 31 out of 42 patients with opaque nodules visible in skull films (calcified cysticercus). In the remaining 11 cases, the characteristic CSF findings were observed in 3, but in 8 cases the only abnormalities were positive complement fixation test or eosinophils. In 14 out of 26 patients with subcutaneous or introacular cysticercus there were the usual CSF changes but in the other remaining cases the CSF was normal. The absence of treatment for brain cysticercosis is consistent with the persistence of CSF abnormalities in the specimens examined during the course of this disease. This calls for an integrated prophylactic to all Latin-American countries in order to exterminate this serious disease for the well-being of the next generation.
Brain Diseases↗
Comparison of indirect fluorescent antibody (IFA) with complement fixation (CF) tests for diagnosis of Babesia spp infections in Colombian cattle.
A total of 372 serum samples were collected from Colombian cattle before and during the course of natural Babesia spp. infection on the North Coast of Colombia. The serum samples were used to compare indirect fluorescent antibody (IFA) with complement fixation (CF) tests for diagnosis of babesiosis. The IFA technique detected Babesia argentina antibodies an average of 4.0 weeks earlier than the CF test and Babesia bigemina an average of 2.5 weeks earlier. Both IFA and CF were capable of differentiating B. argentina and B. bigemina infections, however in some cases cross reactions were observed. In general IFA titers were at relatively high levels of 1:640 to 1:5120 in comparison with CF titers of trace to 1:80. In cases of mortality due to babesiosis, both IFA and CF serologic techniques were very useful in indicating the cause of death. Although both IFA and CF are laboratory tests, the IFA technique had advantages over the CF in simplicity, economy and speed of performance.
Animals↗
Hepatitis B circulating immune complexes. Characterization by radioimmunoprecipitation--PEG assay (RIPEGA).
Incidence of circulating immune complexes (IC) was investigated in carriers of hepatitis B antigen (HBAg) and/or anti-HB antibodies (anti-HBAb). Three methods were used: radiolabelled C1q binding test (C1qBT), complement fixation test (CFT), and optical density (OD) measurement after dissolution of 3% polyethylene glycol (PEG) precipitate of serum. A highly significant correlation was obtained between these three techniques. The level of IC was higher in carriers of HBAg without anti-HBAb, than in others. The characterization of HBAg and anti-HBAB in IC was carried out by a new procedure, the radioimmunoprecipitation-PEG assay (RIPEGA), This sensitive and reproducible test was performed by incubation of 125I-HBAg or 125I-HBAG with 3% precipitate of the carriers' sera. Separation of free from complexed 125I-HBAg or 125I-HBAb was achieved by PEG precipitation. A highly significant correlation was found between the levels of circulating IC evaluated by the C1q-BT and the quantities of HBAg or anti HBAb measured by RIPEGA. RIPEGA was used to quantify HBAg and anti-HBAb present in serum from HBAg and/or anti-HBAb carriers, confirmed by a radioimmunoassay. In preliminary results, RIPEGA was shown to be more sensitive than classical radioimmunoassay.
Antibodies↗
Humoral and cell-mediated immune responses in non-pregnant heifers following infection and vaccination with Brucella abortus.
Humoral and cell-mediated-immune responses to Brucella abortus were observed in non-pregnant heifers following infection alone; infection followed by vaccination; vaccination followed by infection; and vaccination alone. The humoral responses, as measured by the Rose Bengal test (RBT), complement fixation test (CFT), indirect haemolysis test (IHLT) and the enzyme-linked immunosorbent assay (ELISA) tended to be immediate and transient following infection alone, infection following vaccination and vaccination alone. However, when vaccination was superimposed on infection, reactions were maintained for at least 2 years. The cell-mediated-immune (CMI) responses were assessed by the lymphocyte stimulation test. The responses occurred after the humoral responses had peaked and were present for periods of 6-22 weeks. However, the level of stimulation was greater following infection than following vaccination, and the response when vaccination was superimposed on infection was present for less than 6 months.
Animals↗
Evaluation of a delayed-type hypersensitivity test for the diagnosis of Brucella abortus infection in cattle.
The delayed-type hypersensitivity (DTH) test was used to diagnose brucellosis in two cows experimentally induced with brucellosis, and 176 dairy cows from a farm suspected of brucellosis. DTH test results were compared with results of the milk ring test, the serum agglutination test, the complement fixation test and the Coombs test. Cows positive in the DTH test and in one of the other tests were examined bacteriologically. In experimentally infected animals the DTH test was positive 10 days after infection, 1-4 weeks before serologic tests indicated brucellosis. Although the DTH test was positive during the whole experiment, on the one occasion when serologic titres were high, it was negative. Of the 176 dairy cows, 45 were positive in one or more serologic tests. In twelve cows (29%) the diagnosis was inconclusive because they were positive in only one of the serologic tests. In these cases the DTH test confirmed the infection. Three cows with high serologic response tested negative in the DTH test. B. abortus was isolated from 13 of 15 cows examined. We conclude that when serologic results are ambiguous, the DTH test is a useful additional technique for diagnosing brucellosis.
Animals↗
Immunopathology of experimental Brucella abortus strain 19 infection of the genitalia of bulls.
Antibody responses in serum and semen, and immunoglobulin containing cell (ICC) populations in the genitalia of bulls were compared after inoculating Brucella abortus strain 19 into the seminal vesicles of two bulls (ISV route) and into testes in two other bulls (IT route). Bulls seroconverted as early as 1 week post-infection (PI). Peak serum titres as determined by the serum agglutination test (SAT), complement fixation test (CFT) and ELISA occurred at PI weeks 3, 4 and 5 respectively. Highest titres were in IT inoculated bulls. Seminal antibodies against B. arbotus S19 were demonstrated from 2 weeks PI by both the SAT and the Rose Bengal Test (RBT) and highest titres occurred at PI weeks 3 and 4. Examination of immunoglobulins (Ig) in semen, however, revealed no significant differences of Ig isotypes between infected and control animals at any examination time. When bulls were killed at 7 weeks PI, quantitation of ICC in genital sections stained by the peroxidase-anti-peroxidase method revealed an overwhelming predominance of IgG containing cells in inflamed organs. In all cases IgG1- and IgG2-containing cells were prevalent, and present in approximately equal numbers. IgA-containing cells were second in prevalence in inflamed tissues while IgM cells were always in low percentage. High prevalence of ICC in infected genitalia, associated with elevated specific seminal antibodies but not with increased seminal Ig indicates that most Ig remains localised in tissues and is not transferred into genital secretions.
Animals↗
Assessment of serological response of young and adult sheep to conjunctival vaccination with Rev-1 vaccine by fluorescence polarization assay (FPA) and other serological tests for B. melitensis.
The serological response of young and adult sheep vaccinated conjunctivally with Rev-1 vaccine was assessed by fluorescence polarization assay (FPA), Rose Bengal test (RBT), complement fixation test (CFT), modified Rose Bengal test (m-RBT), indirect ELISA (i-ELISA) and competitive ELISA (c-ELISA), at different post vaccination intervals. One hundred and thirty six adult sheep and 64 lambs were used in the study. The vaccinated animals were bled prior to vaccination (0 day) and thereafter at 21st, 42nd, 35th, 63rd, 91st, 125th, 159th, and 223rd and 330th day post vaccination. The majority of animals (young and adult) showed positive reaction by FPA, RBT, CFT, m-RBT and c-ELISA 21 days post vaccination, whereas by i-ELISA at 42 days. All tests perform equal when animals vaccinated as young are tested 125 days (4 months) post vaccination. In case of animals vaccinated at adulthood, FPA, RBT, CFT and c-ELISA perform equal if the animals are tested 223 days (approximately 8 months) post vaccination. I-ELISA and m-RBT show low specificity if ewes vaccinated at adulthood are tested 330 days (11 months) post vaccination. If control of brucellosis in sheep is based on conjunctivally vaccination of lambs with Rev-1, the vaccinated animals can be tested by any test used for diagnosis of B.melitensis infection accurately at least 4 months post vaccination. If brucellosis control is based on mass vaccination the use of m-RBT and i-ELISA is not recommended for testing adult animals at least for 330 days (11 months) post vaccination due to tests low specificity. Further research is needed so the appropriate cut-offs to be established for FPA, c-ELISA or i-ELISA to become valuable tools for the eradication of Brucella spp. infection in small ruminants in areas where vaccination is practiced.
Animals↗
Diagnosis of bovine brucellosis using a homogeneous fluorescence polarization assay.
To evaluate the fluorescence polarization assay (FPA) for the serological diagnosis of bovine brucellosis, 118 sera from cattle which were culture positive for Brucella abortus, 1751 sera from cattle from premises containing cattle infected with B. abortus, 1222 sera from cattle vaccinated with B. abortus strain 19 and 1199 sera from cattle with no evidence of brucellosis were tested in Argentina, Chile, Mexico and in the American states of Iowa, Missouri and Texas. Initial determination of serological positivity and negativity was based upon reactivity in currently used serological tests, consisting of a rapid screening test, the rose-bengal or the buffered plate antigen tests, followed by a second serological test, the complement fixation test. Sensitivity of the FPA (sera from culture positive animals) ranged from 87.5% to 100%. Serological positivity of cattle from infected premises ranged from 65.5% to 99.0% while the % negative cattle in herds without evidence of brucellosis was between 94.9 and 100%. Of B. abortus strain 19 vaccinated cattle which were positive in at least one in-use serological tests, 88.2% were negative in the FPA. In contrast, previous Canadian studies, sensitivity values were 99.0% and 100% and the specificity in both cases was 100%. This discrepancy was probably due to the use of less well characterized sera in the current study.
Animals↗
Field trial of the brucellosis fluorescence polarization assay.
Fluorescence polarization assay (FPA) is a homogeneous technique which was applied to the serological diagnosis of bovine brucellosis. Because of its simplicity and because it may be performed very rapidly, it was an ideal test to adapt to field use. The FPA was used to test cattle on six dairy farms in Baja California, Mexico. Anticoagulated blood, serum, and milk were collected from each animal. The anticoagulated blood was tested immediately on the farm while serum and milk were tested subsequently in the laboratory. Cattle on one farm (n = 140) were thought not to be infected with Brucella abortus and the other farms were thought to have high prevalence of the infection. The whole blood FPA (FPA(bld)) did not detect antibody in any of the cattle on the first premise. This finding was confirmed using a number of other serological tests, including the buffered antigen plate agglutination test, the complement fixation test, the indirect and competitive enzyme immunoassays, and the FPA using serum and milk. Cattle on the other premises (n = 1122) were tested in a similar fashion. The sensitivity of the FPA(bld), relative to the serum FPA (considered the definitive test), was 99.1% and the relative specificity of the FPA(bld) was 99.6%. These results compared favourably with those obtained using the other serological tests.
Animals↗