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An immunosorption assay for antibodies to spermatozoa: comparison with agglutination and immobilization tests.

We have developed an enzyme-linked immunosorption assay (ELISA) with an antigen extract made by treatment of freeze-thawed sperm pools with 0.3 M lithium 3,5-diiodosalicylate (LIS). This procedure is quick, safe, and simple to perform in a clinical laboratory. When the LIS antigen preparation was compared by ELISA with whole sperm and several other antigen extracts, it was found to be superior in detecting human antisperm antibodies related to infertility; it gave less variability, better precision, and fewer false-positive reactions than whole sperm fixed to the wells as antigen. The antigen was stable when stored at -20 degrees C. In one experimental series, serum samples from 18 normal control subjects and 159 infertility patients with positive sperm-immobilizing titers, positive sperm-agglutinating titers, or both, were tested by ELISA with LIS antigen; the correlation yielded a P less than or equal to 0.0001. Based on another series of 156 samples from patients with positive antibody titers by the sperm agglutination test and 30 sera from normal humans, the predictive value of the test was 96%. In a third series of 162 serum samples obtained from 82 women and 80 men, we found no difference in the test results based on sex. The assay is specific for the antibody binding portion of the immunoglobulin. Absorption of positive sera with sperm but not red blood cells markedly reduces the response. In addition to being more efficient and precise than standard methods, the ELISA eliminates the need for fresh sperm and provides data that can be objectively interpreted.

Antibodies↗

The sensitivity and specificity of an agglutination test for antibodies to streptococcal extracellular antigens: a quantitative analysis and comparison of the Streptozyme test with the anti-streptolysin O and anti-deoxyribonuclease B tests.

As a part of studies of streptococcal infections of the upper respiratory tract, sera from 142 individuals (mean age 11.9 years) with signs and symptoms on tonsillitis or pharyngitis and their family contacts were studied to quantitatively evaluate the sensitivity and specificity of the Streptozyme test. We also compared this agglutination test for streptococcal extracellular antibodies with the antistreptolysin O and antideoxyribonuclease B tests. Using different lots of Streptozyme reagent we found evidence suggesting variation in the strength of the reagent from lot to lot. Evaluation of the group specificity of the Streptozyme test suggests that it may not be specific for antibodies to extracellular products of group A streptococci, since a response to this test was seen in individuals with only non-group A strains isolated from their upper respiratory tracts. In patients with group A streptococci isolated from the upper respiratory tract, the quantitative sensitivity of the antibody response as measured by the Streptozyme test is comparable to, but no greater than, the ASO or anti-DNase B tests. Our analysis of upper limits of normal for the Streptozyme test in the study population indicates that previous recommendations for values for elevated titers are too low, especially for predominantly pediatric populations, so that previous reports of patients demonstrating an antibody response to Streptozyme-measured antibodies may include a significant number of patients with "normal" levels. This study indicates the need for both further documentation of standardization of the reagents used in this agglutination test and additional quantitative studies of the response measured by Streptozyme.

Adolescent↗

TrypTect CIATT--a card indirect agglutination trypanosomiasis test for diagnosis of Trypanosoma brucei gambiense and T. b. rhodesiense infections.

A simple and rapid test, the card indirect agglutination trypanosomiasis test (TrypTect CIATT) is described, for detecting circulating antigens in persons suffering from Trypanosoma brucei gambiense and T. b. rhodesiense infection by latex agglutination. The sensitivity of the test (95.8% for T. b. gambiense and 97.7% for T. b. rhodesiense) was significantly higher than that of lymph node puncture, microhaematocrit centrifugation and cerebrospinal fluid examination after single and double centrifugation. The specificity of the test was also high: 106 blood donor sera as well as sera from 37 patients with malaria, 25 with visceral leishmaniasis, 10 with schistosomiasis, 5 with filariasis and 10 with hydatid disease, from trypanosomiasis-free areas, gave negative results. Eighteen clinical suspects from active disease transmission foci, without microscopically detectable parasitaemia but with a positive test result, were further examined by lumbar puncture and inoculation of blood into mice; 11 (61%) were found to be infected, suggesting that the test had a high positive predictive value. This study showed that TrypTect CIATT is a useful test for rapid diagnosis of both patent and non-patent T. b. gambiense and T. b. rhodesiense infections.

Agglutination Tests↗

Agglutination of intralipid by sera of acutely ill patients.

The serum of over half of a group of acutely ill patients agglutinated "Intralipid' a fat emulsion based on soya bean oil designed for intravenous infusion. This reaction is probably precipitated by C-reactive protein in the presence of calcium ions. Post-mortem examinations of patients who had received intralipid showed evidence of microembolism which could have been caused by agglutination of intralipid. If this is the case then intralipid should perhaps not be given to these acutely ill patients.

Acute Disease↗

Evaluation of a Brucella enzyme immunoassay test (ELISA) in comparison with bacteriological culture and agglutination.

An ELISA test for IgG and IgM antibrucella antibodies was found to be effective in diagnosis of human brucellosis. Assays for IgG and IgM in 30 culture-positive cases gave significant ELISA values. By the standard agglutination test, 10% of these cases gave readings less than 1:160. These are considered insignificant, taking 1:160 as the accepted cut-off value. Moreover, in an extra 135 samples from suspected brucella cases, where only serology was requested (77.6% of all cases), 7.4% were found to have IgM brucella antibodies by ELISA. In all of these, the corresponding agglutination titres were less than 1:80 and hence reported as insignificant. We report the detection of IgG and IgM antibodies in samples from patients with both acute and chronic disease. In few patients with acute disease, only IgM was detected. These findings are discussed in comparison with earlier studies. Finally, the ELISA test, in addition to measuring antibody classes directly, also detects incomplete antibodies. By this, it can efficiently replace the 2 mercaptoethanol test (2ME) and the Coomb's antihuman-globulin test. This saves considerable laboratory cost and time.

Agglutination Tests↗

Development of a particle agglutination assay system for detecting Japanese encephalitis virus-specific human IgM, using hydroxyapatite-coated nylon beads.

Japanese encephalitis virus-specific IgM is a reliable indicator for serodiagnosis of Japanese encephalitis. A particle agglutination (PA) assay system was developed to detect anti-Japanese encephalitis virus IgM in human serum samples. The newly developed PA assay consisted of hydroxyapatite-coated nylon beads and V-bottom 96-well microplates. Hydroxyapatite-coated nylon beads were coated with Japanese encephalitis virus antigens. Japanese encephalitis virus antigen-coated, hydroxyapatite-coated nylon beads agglutinated in the IgM-captured wells when anti-Japanese encephalitis virus IgM-positive serum samples were used. A button pattern was formed at the bottom of the wells when anti-Japanese encephalitis virus IgM-negative serum samples were used. Thirty anti-Japanese encephalitis virus IgM-positive serum samples from Japanese encephalitis-confirmed cases were tested by the PA assay. All these serum samples were determined to be Japanese encephalitis virus IgM-positive. IgM titers determined by the PA assay corresponded to those determined by enzyme-linked immunosorbent assay. The titers were consistent in two independent PA assays. These results indicate that the newly developed PA assay is a reliable method for detecting anti-Japanese encephalitis virus IgM in human serum samples and that this assay will be a suitable diagnostic system especially in rural areas of Asia.

Agglutination Tests↗

Prevalence of agglutinating antibodies to Sarcocystis neurona in raccoons, Procyon lotor, from the United States.

Equine protozoal myeloencephalitis (EPM) is the most important protozoal disease of horses in North America and it is caused by Sarcocystis neurona. Natural cases of encephalitis due to S. neurona have been reported in raccoons, Procyon lotor. We examined 99 raccoons for agglutinating antibodies to S. neurona using the S. neurona agglutination test (SAT) employing formalin-fixed merozoites as antigen. Raccoons originated in Florida (N=24, collected in 1996), New Jersey (N=25, collected in 1993), Pennsylvania (N=25, collected in 1999), and Massachusetts (N=25, collected in 1993 and 1994). We found that 58 (58.6%) of the 99 raccoons were positive for antibodies to S. neurona using the SAT; 44 of 99 raccoons (44%) had titers of > or =1:500. This prevalence is similar to the reported seroprevalence of 33-60% for S. neurona antibodies in horses from the United States using the Western blot test.

Agglutination Tests↗

Development of a fast agglutination screening test (FAST) for the detection of anti-Leishmania antibodies in dogs.

A fast agglutination screening test (FAST) for the detection of anti-Leishmania antibodies in serum samples from dogs with visceral leishmaniosis was developed. The test is based on the direct agglutination test (DAT), but combines a higher parasite concentration with a smaller test volume. In contrast to the DAT, the FAST makes use of only one serum dilution and the results can be read within 3 h as opposed to 18-20 h for the DAT. The FAST was evaluated using serum samples of confirmed cases of the disease and healthy controls collected in the most important endemic regions of canine visceral leishmaniosis, import cases of canine leishmaniosis in a non-endemic country, from non-endemic healthy controls and from dogs with other diseases. The performance of the FAST was compared with standard DAT. In the present study, the FAST had a sensitivity of 93.6% and a specificity of 89.0%. The DAT had a sensitivity of 88.6% and a specificity of 96.7%. Furthermore, using a large panel of serum samples of previously examined DAT positive or negative dogs it was shown that degree of agreement between the two tests was high (95.7%; kappa value = 0.91). The FAST offers the advantages of the DAT based on freeze-dried antigen with respect to stability of the antigen, sensitivity and specificity. Moreover, the FAST allows the rapid screening of a large number of samples, which makes the test very useful for epidemiological screening of large populations of dogs.

Agglutination Tests↗

Comparison of indirect immunofluorescent antibody test and modified direct agglutination test methods for detection of Toxoplasma gondii antibodies in adult sheep in Spain.

A total of 2306 serum samples obtained from adult sheep were analysed for Toxoplasma gondii IgG antibodies by modified direct agglutination test and indirect immunofluorescence assay test. Similar results were obtained with both procedures (seroprevalence of 35.27% for modified direct agglutination test and 33.72% for indirect immunofluorescence assay test at dilution 1:80), but some differences in relation to sample dilution were registered. All the titers assayed (dilution two-fold from 1:40 to 1:320) can be used in diagnosis with both procedures, but titers 1:80 are recommended for screening studies in ovine flocks.

Agglutination Tests↗

RHD antigen density and agglutination in RHD variant red cells.

For the Rhesus categories DIV, DVI, and DVII, agglutination was compared to the number of RHD antigens per cell. We detected 3,100 to 15,400 antigens/cell on DVI. We report examples of anti-D reactivity showing lack of specificity and pointing to the known serologic split in DIV and DVI. Such a split was not found in DVII. Other examples were explained by lack of sensitivity. These results emphasized the need to consider RHD antigen densities, before a serologic split in RHD variant cells is postulated. In this context, flow cytometry may be superior to agglutination titers to determine antigen densities.

Agglutination Tests↗

Hydroxyapatite-coated nylon beads as a new reagent to develop a particle agglutination assay system for detecting Japanese encephalitis virus-specific human antibodies.

BACKGROUND: Detection of Japanese encephalitis virus (JEV)-specific antibodies is done today by hemagglutination-inhibition assay (HIA), neutralization assay (NTA) and enzyme-linked immunosorbent assay (ELISA). These conventional assays are often difficult to perform in diagnostic laboratories with insufficient resources. An alternative antibody detection kit, which is simple, preservable and inexpensive, is needed for extended use in rural areas of Asia. OBJECTIVES: (i) Characterization of a new antigen carrier, hydroxyapatite-coated nylon (Ha-Ny) beads, and (ii) evaluation of the JEV antigen-coated Ha-Ny beads as a reagent to detect anti-JEV antibodies in human serum samples. STUDY DESIGN: We examined the Ha-Ny beads for hydroxyapatite content, precipitation efficiency and protein adsorption ability. We then developed a particle agglutination assay system using the JEV antigen-coated Ha-Ny beads, and tried out the newly developed assay system with reference serum samples. RESULTS: The beads had the ability to adsorb 0.44 mg of lysozyme per gram. Sedimentation speed was 10.2 cm/30 min in phosphate buffered saline (PBS), pH 7.0. Binding of the JEV antigen on Ha-Ny beads was confirmed by scanning electron microscopy (SEM) and ELISA. Eighteen confirmed-human serum samples were tested by the newly developed particle agglutination assay system. The results were consistent with those from HIA, NTA and ELISA. CONCLUSION: The Ha-Ny beads can be applicable to the development of a new JEV antibody-detection kit, which does not require specific laboratory facilities.

Agglutination Tests↗

Characterization of the antibodies detected by the microscopic agglutination test for bovine leptospirosis.

The nature of the antibodies detectable by the microscopic agglutination test for bovine leptospirosis was examined. Density gradient ultracentrifugation, gel filtration and disulphide-bond-reduction experiments indicated that antileptospiral agglutinating activity was present in both IgM and IgG immunoglobulin fractions. This was confirmed by selective precipitation of specific antibody classes and ion-exchange chromatography.

Agglutination Tests↗

Comparison of agglutination, complement fixation and immunofluorescence tests in Campylobacter jejuni infections.

Good antibody responses usually follow infection with Campylobacter jejuni. A comparison of agglutination, complement fixation and immunofluorescence tests was done on 55 sera from 40 sporadic patients with diarrhoeal disease and positive cultures for C. jejuni. Results showed 82% positive with immunofluorescence, 62% by complement fixation but only 38% by agglutination, using two reference strains COP and MEL as antigens. Overall 90% of the 40 patients were positive by one or more serological tests. Paired sera from 15 patients showed a fourfold or greater rise in only five, confirming previous observations that antibody formation occurs early in the course of infection. Results also suggest that different test systems may be detecting antibodies of different specificities. Results confirm the value of serological tests, but further information on serotypes is required for selection of suitable reference strains.

Agglutination Tests↗

Further evaluation of one-point microcapsule agglutination test for diagnosis of leptospirosis.

A total of 100 serum samples including 22 acute phase sera and 39 paired sera collected from clinically diagnosed cases of leptospirosis in Ming-shan County, Sichuan Province, China were examined by the one-point microcapsule agglutination test (MCAT), which was developed in Japan, and by conventional microscopic agglutination tests (MAT). The one-point MCAT is more reactive to IgM antibody than MAT and is superior in detecting antibodies in the early stages of the disease.

Acute Disease↗

One-point method for serological diagnosis of leptospirosis: a microcapsule agglutination test.

This paper describes a simple and rapid microcapsule agglutination (MCA) test. The results obtained by this new test have been compared with those obtained by the microtitre MCA and the microscopic agglutination (MA) test. The procedures required for the new test are easier and can be performed more rapidly than those necessary for the microtitre MCA test. Furthermore, the new test is more sensitive than the MA test in the early stages of leptospirosis. This new test appears satisfactory as a screening test for the early diagnosis of leptospirosis.

Agglutination Tests↗

'Agglutination and flocculation' of stem cells collected by apheresis due to cryofibrinogen.

Collection of peripheral stem cells by apheresis is a well-described process. Here, investigations concerning 'agglutination and flocculation' of stem cells collected from two patients are described. In both cases, cryoproteins were observed and cryofibrinogen was identified using high-resolution two-dimensional electrophoresis. In one case, peripheral stem cells were collected after a second course of mobilization, and the cells were immediately washed at 37 degrees C before being frozen, allowing their use, despite the presence of cryofibrinogen. In the other case, 'agglutination' was reversed by warming the bag, and plasma was removed before freezing.

Agglutination↗

Lectins interact differentially with purified human eosinophils, cultured cord blood-derived mast cells and the myeloid leukaemic cell line AML14.3D10: induction of interleukin-4 secretion is conserved among granulocytes, but is not proportional to agglutination or lectin-glycoprotein interaction.

BACKGROUND: Atopy is closely associated with the cellular T helper type-2 (Th2) phenotype, that is dominated by the pleiotrophic cytokine IL-4. The cellular source of IL-4 has yet to be determined, although basophils have been proposed. Eosinophils and mast cells are likely contenders investigated here, and the eosinophil-like leukaemia line AML14.3D10 is compared to eosinophils as an in vitro culturable model for eosinophils. Lectins can cross-link-specific surface glycoproteins and are found in the ingested (processed foods) and inhaled (airborne pollen grains) human environment. Therefore it is of interest to determine whether lectins can elicit the release of IL-4 from Th2-associated granulocytes other than basophils. METHOD: This study investigated the ability of eosinophils, AML14.3D10 and mast cells to secrete preformed IL-4 in response to stimulation with lectins, and explored molecular mechanisms underlying the interaction. RESULTS: Purified eosinophils and basophils, and cultured mast cells and AML14.3D10 cells were incubated with 1 micro m lectin. Agglutination was scored by microscopy. IL-4 secretion was measured by enzyme-linked immunosorbent assay. Biotinylated lectins were used to determine binding to cells by flow cytometry and in lectin blots of sodium dodecyl sulphate (SDS) gels. DISCUSSION: Purified human eosinophils, AML14.3D10 cells and cultured mast cells secrete IL-4 with a pattern similar to that found in basophils when stimulated with a panel of reactive and unreactive lectins. The lectin SNA induces IL-4 secretion from mast cells and basophils, but not from eosinophils or AML14.3D10. Eosinophils appear to secrete only pre-formed IL-4, whereas mast cells may synthesize IL-4 on ligation with the lectin LCA. Lectins that agglutinate the granulocytes investigated do not necessarily induce secretion of IL-4. Lectins that elicit secretion of IL-4 bind more to eosinophils than unreactive lectins as determined by flow cytometry and lectin blotting of SDS gels. CONCLUSION: As granulocytes with functions related to that of basophils, eosinophils, AML14.3D10 and cultured mast cells respond to stimulation with lectins similarly to basophils. This emphasizes the possibility that eosinophils and mast cells may be linked in their cellular heritage as the cellular partners, and lectins as ligands, may contribute to the maintenance of a Th2-favoured microenvironment that is thought to underlie the allergic march.

Agglutination↗

Application of the gel test in IgG subclassing--a comparison of two agglutination assays.

BACKGROUND AND OBJECTIVES: IgG subclasses of anti-D seem to play some role in hemolytic disease of the newborn, but there has been disagreement as to its exact nature. The aim of our study was to evaluate a new technique for IgG subclassing of anti-D and to compare it to an established test. MATERIALS AND METHODS: In 31 cases of RhD immunization, we have compared two simple agglutinating assays for subclassing anti-D: an established V-well microtiter tray assay and a new gel test assay. Polyclonal rabbit anti-IgG agglutinating antibodies were tested against sensitized D-positive red blood cells by both assays. RESULTS: The anti-D concentration in tested sera varied between 0.1 and 81 micrograms/ml (0.5-405 IU/ml). Both assays were simple to perform and the results correlated well. CONCLUSIONS: The gel test had two advantages: quick performance and easy interpretation.

Agglutination↗