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PubMed1985

Use of ELISA for measuring the extent of serological cross-reactivity between plant viruses.

The degree of antigenic relatedness between two plant viruses is commonly expressed by a serological differentiation index (SDI) which corresponds to the average number of two-fold dilution steps separating homologous from heterologous precipitin titers. Results obtained with several tobamo- and tombusviruses indicated that the indirect form of the enzyme-linked immunosorbent assay (ELISA) can also be used for calculating SDI values. This was achieved by comparing the antiserum dilutions that lead to the same absorbance measurements (for instance 1.0) when homologous and heterologous viruses are assayed by ELISA. SDI values calculated from ELISA were similar to those obtained from precipitin tests. Because of its greater sensitivity, ELISA is able to quantify weak cross-reactions that are not detectable by precipitin tests.

Antigens, Viral↗
PubMed1956

Identification of blood meals of blood-sucking arthropods.

The identification of blood meals of blood-sucking arthropods requires a test which is sensitive enough to detect even partially digested blood and specific enough to identify the various hosts. The technique of preference is the precipitin test which makes use of the specific combination of the serum proteins of the blood. The preparation of the blood meal extract and the procedure for the absorption of the antisera is described and various methods of performing the precipitin test are mentioned. When the hosts involved are closely related to each other it is necessary to use the inhibition test. The blood meal will specifically inhibit, under specified conditions, the agglutination of tanned and sensitized red blood cells which is caused by a suitable antiserum. The procedure adopted for the identification of blood meals derived from a large variety of hosts is described in detail.

Animals↗
PubMed1978

Counterimmunoelectrophoresis in the detection of antibodies to Schistosoma japonicum.

Counterimmunoelectrophoresis (CIE) was used to detect antibodies to Schistosoma japonicum soluble egg antigen in 118 sera from people living in a schistosomiasis endemic area in the Philippines. The sera were also tested for antibodies by the circumoval precipitin test (COPT); 53% were found positive by CIE and 48% positive by COPT. No significant differences were found between the tests (P = 0.18 by McNemar's test). Cross-reactions with sera from patients with intestinal capillariasis and monkeys with experimental angiostrongyliasis were not found and no false reactions were detected with sera from "normal" controls. The CIE test as used in the present studies was found to be comparable to the COPT in sensitivity and specificity as related to cross-reactivity with sera from nematode infections such as intestinal capillariasis and angiostrongyliasis. Results are usually available quickly with nearly 70% of any reactions occurring within 1 h. The test should be of value in seroepidemiologic surveys in schistosomiasis-endemic areas.

Adolescent↗
PubMed1968

Rapid, sensitive assay for staphylococcal enterotoxin and a comparison of serological methods.

Reversed passive hemagglutination was used to assay enterotoxin in culture filtrates and in food samples. With cells tanned and then sensitized with antitoxin globulin and preserved with either formaldehyde or pyruvic aldehyde, as little as 0.0007 mug of enterotoxin was detectable. The results of hemagglutination tests compared well with those obtained by quantitative precipitin tests or by immunodiffusion, but hemagglutination was 50 to 100 times more sensitive than the immunodiffusion technique. In addition, results of the hemagglutination test were available within a few hours, and neither elimination of interfering proteins from food extracts nor concentration of the sample, both of which are necessary for immunodiffusion, was required for this procedure.

Antitoxins↗
PubMed1980

Antibody responses in murine schistosomiasis and fascioliasis.

Antibody responses in mice with a primary infection of either Schistosoma mansoni or Fasciola hepatica were studied, using antigen preparations from both species. S. mansoni adult worm extracts (Ouchterlony, indrect hemagglutination) detected schistosomiasis in mice by 5-6 weeks, but did not detect fascioliasis through 12 weeks of infection. S. mansoni soluble egg antigen (Ouchterlony, enzyme-linked immunosorbent assay--ELISA) reacted with the sera of mice infected with S. mansoni by 6-7 weeks of infection; only ELISA reacted with the sera of mice infected with F. hepatica (by 3 weeks of infection). The circumoval precipitin test was specific only for mice infected with S. mansoni, being positive by the 9th week of infection. F. hepatica adult worm extract precipitated (Ouchterlony) the sera of mice with schistosomiasis (7 weeks) and fascioliasis (2 weeks).

Animals↗
PubMed1983

Comparative evaluation of commercial latex agglutination and coagglutination reagents for groups B, C, and D mastitis streptococci.

A total of 144 strains of mastitis streptococci (groups B, C, and D) were grouped by conventional technique (Lancefield precipitin test) latex agglutination (LA), and coagglutination (CA). The LA correctly grouped 98% and the CA grouped 100% of strains on the test when the instructions of the manufacturers were followed. Sensitivity of both tests was improved for strains belonging to group D when extracts from colonies grown on sheep blood agar plates were used for grouping. Nonspecific reactions between groups C and B were observed only with one kit of LA reagents, whereas cross-reactions were recorded with all groups when CA reagents were used.

Agglutination Tests↗
PubMed1964

ELECTROPHORETIC SEPARATION OF CONSTITUENTS OF PARTIALLY PURIFIED M PROTEIN OF STREPTOCOCCUS PYOGENES.

Pierce, William A., Jr. (Tulane University, New Orleans, La.). Electrophoretic separation of constituents of partially purified M protein of Streptococcus pyogenes. J. Bacteriol. 88:912-921. 1964.-Partially purified M protein of a group A, type 12 strain of Streptococcus pyogenes was studied by use of chemical, electrophoretic, and immunological techniques. It was demonstrated in immunodiffusion tests that the antigen contains multiple precipitating components. The type-specific antigen was identified, and evidence was presented that, in some instances at least, the cross-reactions observed between this type 12 M protein and heterologous antisera in immunodiffusion tests involve contaminating antigens rather than the component which precipitates with adsorbed homologous-typing antiserum. In passive hemagglutination tests where M protein was adsorbed to tanned sheep erythrocytes, it was found that antisera suitably adsorbed to show good specificity in capillary precipitin tests nevertheless still contain cross-reactive antibodies which are detectable by this more sensitive technique. Electrophoresis on starch paste separates some of the components of partially purified M protein, so that a fraction can be obtained which has fewer precipitating antigens, as determined in immunodiffusion tests, and which is less cross-reactive in passive hemagglutination tests with heterologous unadsorbed antistreptococcal antisera.

Animals↗
PubMed1978

Direct-plate serological grouping of beta-hemolytic streptococci from primary isolation plates with the Phadebact streptococcus test.

The grouping of beta-hemolytic streptococcal isolates by a new direct-plate procedure employing Phadebact Streptococcus Test reagents was compared with the results obtained with the 4- and 24-h Phadebact grouping procedure and with the Lancefield grouping obtained with a capillary precipitin test. The new procedure employed a modification of the Phadebact procedure that permitted the grouping of streptococci on glass slides with a minimum of five primary isolated colonies. When only five to eight colonies were available for direct testing with each Phadebact reagent, coagglutination was better manifested when the colonies were disaggregated on a glass slide in a loopful of Tween 80 solution. Further enhancement of the coagglutination reaction was effected when the respective Phadebact reagents were employed in relatively small volumes. The direct-plate procedure permitted the correct identification of 127 out of 129 betahemolytic isolates. The 4-h method correctly identified 192 of the 200 streptococci tested. All of the 200 isolates tested by the 24-h procedure and the Lancefield grouping were correctly identified. The direct-plate Phadebact procedure affords the clinical microbiologist a rapid and reliable means of identifying groups A, B, C, and G beta-hemolytic streptococci. When sufficient numbers of primary colonies are not available for the direct procedure, the 4- or 24-h procedures may be employed.

Agglutination Tests↗
PubMed1970

Serological studies with human papova (wart) virus.

Methods for demonstrating antibody to wart virus by complement fixation and passive haemagglutination tests are described and compared with the precipitin test of Almeida & Goffe (1965). The results reveal the much greater sensitivity of the passive haemagglutination method, particularly in the detection of the immunoglobulin M class of antibody. Both complement-fixing and precipitating antibody were detected in sera from patients whose warts had undergone a spontaneous resolution.The presence of antibody to wart virus was demonstrated in sera from persons who had had warts up to 10 years previously, and in a few cases from those who thought they had never had warts.The antigenic identity of virus from hand warts and plantar warts of the simple and mosaic types was revealed, and some evidence was obtained for similar identity of the virus from genital warts.

Adolescent↗
PubMed1975

Use of radioimmunoassays to determine the concentration of streptococcal group-specific antibodies in rabbit antisera.

A radioimmunoassay was developed for the quantitation of antibodies to the Group A, A-variant, and C carbohydrates in rabbit streptococcal antisera. The assay employs radiolabeled purified Group carbohydrate which has been tyrosylated to allow for incorporation of 125-I. This assay has an advantage over the intitative precipitin test because it measures non-precipitating antibody in addition to precipitating antibody. Furthermore, 7S anti-IgG in rabbit antisera give a falsely elevated value for the antibody concentration in the quantitative precipitin test. This did not occur with the radioimmunoassay. The assay described is reproducible, sensitive, and uses little antisera.

Adsorption↗
PubMed1976

A comparison of some serological tests for bluetongue virus infection.

The plaque neutralization, complement fixation, and agar gel precipitin tests were compared by measuring bluetongue virus antibody in 137 serums from experimental animals (cattle and sheep) and suspected field reactors (cattle and deer). In general, the tests agreed well with each other. Plaque neutralization titers began earlier than the other two and went much higher than the complement fixation titers. Plaque neutralization titers usually peaked between two and three weeks after exposure and complement fixation titers from four to six weeks. The greater sensitivity of the plaque neutralization test allowed the detection of all complement fixation and agar gel precipitin reactors whereas occasionally the latter two tests failed to detect plaque neutralization reactors.

Agar↗
PubMed1979

Microbiological and serological studies of farmers' lung in Finland.

Sera from few Finnish patients with clinical farmers' lung react in precipitin tests with extracts of the thermophilic actinomycetes that commonly cause the disease elsewhere. Hays associated with the disease in Finland showed less evidence of spontaneous heating and contained fewer actinomycete spores than British hays. Only Thermoactinomyces vulgaris was sometimes abundant. Some species of mesophilic fungi were more abundant than in Britain and one, Aspergillus umbrosus, reacted with most sera from farmers' lung patients in precipitin tests. A panel of antigens, including thermophilic actinomycetes, A. umbrosus and other species of the Aspergillus glaucus group, is recommended for screening farmers' lung sera.

Adult↗
PubMed1985

The development and evaluation of an ELISA for the detection of antibodies to caprine arthritis-encephalitis virus in goat sera.

An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of antibodies to caprine arthritis encephalitis virus (CAEV) in goat sera. The system was evaluated using some 1500 sera from flocks of known clinical history. From this data the interpretation limits of the system were determined. The ELISA system was compared with a gel precipitin test using 5800 sera. Of the positive sera, ELISA detected 97.3% and AGPT 61%. Further evaluation was made using 60 sera of known CAEV reactivity from the USA, and results agreed 100%. Indications are that antibody to the envelope glycoprotein gp135 is being detected. The ELISA system is more sensitive than the precipitin test and is presently being used in a CAEV flock accreditation scheme.

Journal Article↗
PubMed1992

Insects feeding on desert bighorn sheep, domestic rabbits, and Japanese quail in the Santa Rosa mountains of southern California.

Desert bighorn sheep (Ovis canadensis cremnobates), a domestic rabbit (Oryctolagus cuniculus), and Japanese quail (Coturnix japonica) were used as bait animals to collect blood-feeding flies in an area of active blue-tongue and epizootic hemorrhagic disease virus transmission. Precipitin tests were used to confirm the blood source where feasible. Eight species of Culicoides, members of the Leptoconops kerteszi group, Simulium spp., Anopheles franciscanus, and Stomoxys calcitrans were collected from the bighorn sheep. Feeding on the bighorn sheep by Culicoides brookmani (n = 25), C. variipennis (n = 6), C. cacticola (n = 1), and Simulium spp. (n = 3) was confirmed by precipitin testing. Primary species attacking the rabbit were C. brookmani, C. variipennis, and the L. kerteszi group. The quail were attacked primarily by members of the C. copiosus group and the L. kerteszi group.

Animals↗
PubMed1973

Relevance of antigenicity of Candida albicans growth phases to diagnosis of systemic candidiasis.

The antigenicity of the two growth phases of Candida albicans has been compared by using crossed immunoelectrophoresis and double-diffusion techniques. Qualitative and quantitative differences in antigenic composition between the phases have been revealed and moreover a specific mycelial antigenic component demonstrated.It is postulated that the use of specific mycelial antigens for routine diagnostic precipitin testing in patients with suspected systemic candidiasis would give more reliable results than at present obtained with yeast cell antigens.

Antigens, Fungal↗
PubMed1994

Farmer's lung precipitins in Doubs (a department of France): prevalence and diagnostic value.

In a French region where farmer's lung (FL) is common, we determined the prevalence of FL precipitins in dairy farmers and analyzed the relation between the presence of FL precipitins and the clinical probability of the disease. All the exposed dairy farmers of both sexes (n = 2555) from five districts of the Doubs department were asked to respond to a medical and professional questionnaire. A total of 1763 (69%) farmers agreed to participate. Precipitins tests were conducted in 551 (31%) farmers who showed any respiratory symptom and in a random sample of 100 asymptomatic farmers. Serum for each farmer was analyzed by both double diffusion and immunoelectrophoresis against Micropolyspora faeni (MF) and extracts of moldy hay (HE) from Doubs. The 651 farmers were then divided into four groups (G 1-4) with a decreasing probability of FL (G1: typical FL symptoms; G4: asymptomatic farmers). The estimated prevalence of precipitins in the whole population was as follows: 1) by double diffusion, against HE: 83%, against MF: 27%; 2) by immunoelectrophoresis, against HE: 26%, against MF: 19%. There was a close "linear" relation between the prevalence of precipitins detected by immunoelectrophoresis against HE and the symptoms: 51% in G1, 36% in G2, 29% in G3, and 13% in G4. Precipitins detected by immunoelectrophoresis were also related to exposure and geography (more immunization in tableland area than in plain or mountain area). Presence of precipitins detected by double diffusion was not related to symptoms, exposure, or geography.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗