Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “AGGLUTINATION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,513 records · Page 84Linked to original sources
PubMed1992

Plasmodium falciparum: the human agglutinating antibody response to the infected red cell surface is predominantly variant specific.

There is mounting evidence that an important component of the host-protective immune response to Plasmodium falciparum is the antibody response to the altered surface of the infected erythrocyte. The nature of these surface changes and the responses to them have been difficult to analyse because of the diverse nature of the parasite-derived neoantigens (PDN) expressed, because of the additional presence of modified host determinants, and because of the lack of monospecific reagents. We have studied the reactivity of field isolates and laboratory clones with pooled or individual sera using a novel approach which obviates the need for specific antibody. We see marked diversity in PDN but in contrast to previous studies, we also find that the predominant agglutinating antibody response in humans is variant specific. Antibodies which cross-react between different serotypes are rare and react only with a subset of PDN types. These results have implications for mechanisms underlying the development of acquired immunity to P. falciparum.

Agglutination↗
PubMed1978

The preparation of latex particles with covalently bound polyamines, IgG and measles agglutinins and their use in visual agglutination tests.

Carboxylated latex particles were substituted with side arms terminating in primary amine and hydrazine groups. The particles were coupled to aldehyde groups generated on glycoproteins which were treated with sodium periodate. Particles having the alipathic primary amine putrescine hapten as the sole substituent and particles linked to glycoproteins such as measles agglutinins and IgG were used to detect the presence of the corresponding antibodies or antigens in biological fluids by agglutination tests.

Agglutination Tests↗
PubMed1979

Mixed agglutination in microtiter U-trays.

The principle of mixed agglutination with cell cultures was applied to those cells which could not be obtained as monolayer cell cultures. Artificial monolayers of freshly isolated cells from various tissues were prepared in poly-L-lysine-coated wells of a microtiter U-tray. By means of this technique, murine alloantigens, H-2 private specificities and Thy-1 antigens were demonstrated on cells from thymus, brain, spleen, kidney and liver. Ia.2 antigen was detected on splenocytes but not on thymocytes or fibroblast L cells. Evidence was also presented that HLA A and B locus antigens could be demonstrated on human thymocytes. Sensitivity of this test was shown to be at least 100 times higher than that of the standard lymphocytotoxicity test for detection of HLA antigens.

Absorption↗
PubMed1980

Passive gold agglutination. An alternative to passive hemagglutination.

A method is described for coating colloidal gold with protein for use in passive agglutination. Coating of the gold is quick, reproducible and the sterile filtered product is stable over a long period of storage at 4 degrees C. Colloidal gold coated with each of the 4 subclasses of human IgG was tested with rabbit, monkey and goat antisera and found to be compatible with each. The visual properties of coated gold particles resemble blood cells and appear to be equally sensitive.

Adsorption↗
PubMed1985

Studies on microcapsules to replace erythrocytes in the passive agglutination reaction.

Two kinds of microcapsules were made from polyurethane and polyurea. Each capsule had a mean diameter of 6 microns, a specific gravity of 1.10, and was red in color. The capsules were coated with ovalbumin condensed with glutaraldehyde. The coated capsules were agglutinated with anti-ovalbumin antibody. The polyurethane capsule (positive charge) bound more ovalbumin and showed a higher sensitivity than did the polyurea capsule (negative charge) or erythrocytes.

Agglutination Tests↗
PubMed1988

Protein immunoassay based on agglutination of antibody-coated ferric oxide particles.

A novel immunoassay is described based on the agglutination by antigens of antibody-coated ferric oxide (Fe2O3) particles. The procedure for attachment of antibodies to the ferric oxide particles is simple and fast. The assay was used for identification and quantification of gamma-globulin in human serum and in chromatographic fractions as well as of gp70 (an envelope protein from feline leukemia virus) in the culture medium and for identification of the thyroid-stimulating hormone (TSH).

Agglutination Tests↗
PubMed1989

Preparation of diazotized polystyrene latex and its use in agglutination assays.

The preparation of this immunological latex consisted of the following steps: the synthesis of polystyrene, polynitrostyrene, polyaminostyrene and polystyrene diazonium salt latex. The quantities of emulsifier and initiator used in the synthesis of the polystyrene latex were much larger than those used in the conventional method. Reduction of the polynitrostyrene latex involved adding latex dropwise to a large excess of 6% sodium hydrosulphite-2 N potassium hydroxide solution with sodium lauryl benzene sulphonate as an emulsifier. When the mixture was heated at 70 degrees C for 4 h, the emulsion of polyaminostyrene was diazotized. The polystyrene diazonium salt latex obtained was capable of combining with 20-40% by weight of antibody protein. The immunopolystyrene diazonium latex reagents showed a positive agglutination reaction of 78-91% when mixed with serum from patients with leptospirosis and two other infectious diseases. The test, which can be completed within 3 min has been used to assay over 1200 patient samples.

Agglutination Tests↗
PubMed1993

Comparison between direct binding, competition and agglutination assays in the characterization of polyclonal anti-idiotypes against anti-HBs human monoclonal antibodies.

Polyclonal anti-idiotypic antibodies to human monoclonal anti-HBs antibodies (MoAb1) were raised in rabbits and designated Ab2-H1 and Ab2-H2. These Ab2 were characterized using three assays. A direct binding ELISA evaluated specificity towards a panel of human monoclonal antibodies and gamma globulins. Competition radioimmunoassay (CRIA) revealed Ab2 specificities towards Ab1 antigen binding sites by inhibition of HBsAg/Ab1 binding. Ab2-H1 and Ab2-H2 had comparable reactivities in ELISA and CRIA, whereas, using affinity purified Ab2, a fast (10 min) agglutination test (Spherotest) revealed different Ab1/Ab2 binding properties. Ab2-H1 reacted in this Spherotest with the Ab1 against which it was known to be specific (Ab1-H1), whereas in the same assay Ab2-H2 showed no activity towards the variable regions of the Ab1 used for its production (Ab1-H2). When injected into rabbits Ab2-H1 induced anti-HBs Ab3 antibodies but Ab2-H2 did not, thereby confirming the assay results.

Agglutination Tests↗
PubMed1995

Automated reading and processing of quantitative IgG, IgM, IgA, and IgE isotypic agglutination results in microplates. Development and application in parasitology-mycology.

Microplate agglutination techniques represent a simple and commonly used approach for the quantitative or qualitative isotypic analysis of specific antibodies. However, they require optical reading by the investigator and are thus prone to an important degree of variability. In order to solve some of the problems associated with the variability of optical readings, we have used an automatic reader scanning each of the 96 wells of a standard microplate in 32 different locations. The inherent advantages of the automatic reader were further maximized by coupling it to a dedicated computer running customized software designed to process data coming on-line from the spectrophotometer. This approach has been applied to the diagnosis of human toxoplasmosis and candidosis. Suspensions of Toxoplasma gondii tachyzoites or of sensitised erythrocytes were used for the determination of IgG antibodies or the quantification of IgM, IgA, or IgE specific isotypes. This procedure allows the simple and reproducible collection of objective results. Moreover, it permits a reduction in cut-off values and direct interpretation of results with automatic conversion of scores into titer, units, index, or into any other scale appropriate for standardization purposes.

Agglutination Tests↗
PubMed1981

The direct agglutination test for chronic Chagas's disease. The effect of pre-treatment of test samples with 2-mercaptoethanol.

The relative sensitivity and relative specificity of the direct agglutination (DA) test for the diagnosis of human Trypanosoma cruzi infection were studied in human serum samples, with and without previous treatment with 2-mercaptoethanol (2-ME), which were obtained from different areas of Brazil. Results obtained with these tests were related to those obtained with the indirect immunofluorescence (IIF) and indirect haemagglutination (IHA) tests. The DA test results from the sample not previously treated with 2-ME did not agree with those from the IIF and IHA tests. On the other hand, the DA test results from the sample previously treated with 2-ME agreed significantly (99.22%) with those from the IIF and IHA tests.

Agglutination Tests↗
PubMed1986

A simple and economical direct agglutination test for serodiagnosis and sero-epidemiological studies of visceral leishmaniasis.

A simple and economical direct agglutination test for the detection of visceral leishmaniasis is described. Trypsin-treated, Coomassie Brilliant Blue-stained, formalin-preserved promastigotes were used as antigen in re-usable V-well microtitre plates. In 21 patients with recent kala-azar, titres of 1:51200 or higher were found. Cured kala-azar patients treated 4 to 14 months before testing, showed titres in the range of 1:3,200 to greater than 1:51,200. Healthy and diseased controls had titres below 1:1,600 with the exception of African trypanosomiasis patients who showed titres of 1:200 to 1:12,800, overlapping with the titres of cured kala-azar patients. Where trypanosomiasis is not a consideration, a titre of 1:1,600 could be considered indicative of visceral leishmaniasis, the sensitivity and specificity were then 100%. The test was applied to sera of 280 inhabitants of Baringo District, a known focus of visceral leishmaniasis in Kenya. When treated cases were included, the test showed a sensitivity of 100% and specificity of 99.3%. This test could be used in district hospitals and health centres in endemic areas as an aid in diagnosis of kala-azar and in the field for sero-epidemiological studies.

Agglutination Tests↗
PubMed1987

Evaluation of a newly developed direct agglutination test (DAT) for serodiagnosis and sero-epidemiological studies of visceral leishmaniasis: comparison with IFAT and ELISA.

A newly developed direct agglutination test (DAT) for visceral leishmaniasis, IFAT and ELISA were applied to sera of patients with visceral leishmaniasis, African and American trypanosomiasis, other parasitic infections and healthy controls. The sensitivities of the 3 tests were comparable (96.3% to 100%); excluding patients with African and American trypanosomiasis, the specificities of DAT and IFAT were 100% and ELISA 87.3%. When trypanosomiasis sera were included, the specificities were 72.6%, 94.3% and 79.4% in DAT, IFAT and ELISA respectively. In 273 sera from a leishmaniasis endemic area (Baringo District, Kenya), the sensitivity was 80% in DAT and IFAT and 60% in ELISA, specificities being 99.6% (DAT), 98.5% (IFAT) and 62.5% (ELISA). As the new DAT is economical and easy to perform, it is recommended for sero-epidemiological field work on visceral leishmaniasis.

Agglutination Tests↗
PubMedDate not supplied

Evaluation in Papua New Guinea of a urine coagglutination test and a Widal slide agglutination test for rapid diagnosis of typhoid fever.

Two simple rapid tests for the laboratory diagnosis of typhoid fever were evaluated, a coagglutination test for detecting Salmonella typhi antigens in urine and a Widal slide agglutination for detecting serum antibodies. Ninety-two culture-confirmed typhoid cases were compared with 64 non-typhoid fever patients, 50 close contacts of typhoid patients, 30 vaccinated staff and 72 healthy community members. A strong urine Vi coagglutination was found to be 86.5% sensitive and 91.8% specific for typhoid, but was not always easy to read. The slide Widal H was found to be 99% sensitive and 95% specific whereas the slide Widal O was 98% sensitive and 98% specific. These data suggest that a single slide Widal O, at a reciprocal titre of 40, is the most suitable rapid test for the diagnosis of typhoid in a population with low typhoid antibody levels in the community, few other cross-reacting Salmonella infections, and a tendency for patients to present late in the infection.

Adolescent↗
PubMedDate not supplied

A comparison of the direct agglutination test and enzyme-linked immunosorbent assay in the sero-diagnosis of leishmaniasis in the Sudan.

The sensitivity and specificity of the direct agglutination test (DAT) and the enzyme-linked immunosorbent assay (ELISA) were compared for the sero-diagnosis of visceral (VL) and cutaneous (CL) leishmaniasis in Sudanese patients. All the sera from parasitologically confirmed cases of VL were positive in both ELISA and DAT. Some minor discrepancies were apparent between the two tests in patients with clinical signs of VL, but in whom VL was not confirmed parasitologically. In parasitologically confirmed CL both tests performed equally badly, with the DAT detecting 67% of cases and ELISA 60%. For the sero-diagnosis of VL, ELISA and DAT performed equally well, but on grounds of simplicity and low cost the DAT was preferred.

Agglutination Tests↗
PubMedDate not supplied

The value of a direct agglutination test in the diagnosis of cutaneous and visceral leishmaniasis in Ethiopia.

The usefulness and sensitivity of a direct agglutination test (DAT) in the diagnosis of cutaneous leishmaniasis due to Leishmania aethiopica infection has been investigated. Formalin-fixed, trypsin-treated and Coomassie blue-stained Leishmania promastigotes of various origins were used as antigens. L. major, L. donovani, L. aethiopica but not L. tropica antigen preparations were able to distinguish sera from individuals infected with Leishmania from sera of uninfected controls, although the titres of sera from patients with localized cutaneous leishmaniasis were low. Comparable results were obtained when the same sera were tested using freshly prepared antigen or antigen stored for 10 months at 4 degrees C. The assay was also used to monitor improvement of disease status following treatment of diffuse cutaneous leishmaniasis patients, and it was found to correlate well with the changing clinical status of the patients.

Adolescent↗
PubMedDate not supplied

Direct agglutination test for diagnosis and sero-epidemiological survey of kala-azar in the Sudan.

132 patients with suspected kala-azar (visceral leishmaniasis) were included in a prospective study to compare the performance of the direct agglutination test (DAT) with smears of lymph node, bone marrow and splenic aspiration. A titre greater than 1:3200 was considered positive. 67 patients provided positive smears and 65 were smear-negative. Compared with the results obtained from smears, the sensitivity of the DAT was 94% and its specificity 72%. Of 18 patients who were negative by smears but positive by DAT, 3 were treated on strong clinical suspicion of kala-azar and responded well to therapy. One other patient had post-kala-azar dermal leishmaniasis. Of the remaining 14, 8 were tested with the leishmanin skin test; 6 gave a positive result, suggesting past or sub-clinical infection. In 4 smear-positive patients, the DAT was negative; in 2 of these, the test remained negative during 6 months' follow-up. In a sero-epidemiological survey in a camp for displaced people, 30 of 600 sampled individuals gave a positive DAT. Of these, 11 had been treated for kala-azar; 4 others were leishmanin positive. The DAT is a useful screening test (sensitivity 94%; predictive value of a negative test 92%), but it does not differentiate between past kala-azar, sub-clinical infection and active disease.

Agglutination Tests↗
PubMedDate not supplied

Kala-azar: a comparative study of parasitological methods and the direct agglutination test in diagnosis.

In a comparative study 88 patients were diagnosed as suffering from kala-azar (visceral leishmaniasis) using 3 parasitological methods simultaneously. Splenomegaly was absent in 4 cases. In 84 patients with splenomegaly, splenic aspiration appeared to be the most sensitive method (96.4%), followed by bone marrow aspiration (70.2%) and lymph node aspiration (58.3%). There was no relation between titres in the direct agglutination test and parasite load as determined by the number of parasitological methods which were positive or parasite density in splenic aspirates. Splenic aspiration and bone marrow aspiration were compared as an assessment of cure in kala-azar. In 6 (13%) of 46 patients tested, parasites were found, all by splenic aspiration. Bone marrow showed parasites in one of these. The literature with regard to parasitological investigations before and after treatment is reviewed.

Agglutination Tests↗
PubMed1988

Effects of serum versus plasma on agglutination of antibody-coated indicator cells by human rheumatoid factors.

Plasma and serum contain an inhibitor (I) of the agglutination of rabbit IgG-coated sheep erythrocytes by human rheumatoid factor (RF). Plasma but not serum contains an inhibitor of the inhibitor (I/I) which allows RF to interact with its target. In normal blood, there is more I than I/I, and I can be removed by solid-phase chromatography through concanavalin A (Con A). Plasma I/I is heat labile being eliminated by heating at 56 degrees C for 30 min. Addition of exogenous calcium clots EDTA plasma, causing an irreversible loss of I/I, and suggesting its involvement in the clotting cascade. The absence of I/I from Factor V-deficient plasma and destruction of I/I by Russell's viper venom indicate I/I either is associated with or is a part of Factor V. These findings suggest a balanced interplay between I and I/I, and indicate results of immunological tests done in vitro may not accurately reflect immune function in vivo. This seems to represent an unexplored link between hemostasis and immunity.

Agglutination Tests↗