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PubMed1991

Comparative evaluation of five agglutination techniques and a new miniaturized system for rapid identification of methicillin-resistant strains of Staphylococcus aureus.

The speciation of methicillin-resistant Staphylococcus aureus (MRSA) poses a significant diagnostic problem when rapid identification methods such as slide agglutination tests, are used, because of the high proportion of false-negative reactions. 150 perfectly identified MRSA strains were tested on 5 commonly used agglutination reagents ("Bacto staph latex test", "Monostaph", "Pastorex staph", "Staphaurex", and "Staphyslide test") in comparison with a new micromethod ("RAPIDEC staph") which detects a type of staphylocoagulase within 2 hours by a fluorescence test. The "RAPIDEC staph" reagent enabled identification of all the MRSA while the agglutination tests gave poorer results: "Monostaph" correctly identified 64.6% of strains, "Staphyslide", 59.3%, "Bacto staph latex test", 44.6%, "Pastorex staph", 38.6% and "Staphaurex", 28.6%. These results show that agglutination slide tests are not reliable enough for the identification of MRSA which are more and more encountered in hospital wards. The authors recommend not to use slide agglutination methods. They suggest the tube test for coagulase which is the reference technique, although it is time-consuming and not well standardized. The results of this evaluation encourage the use of the "RAPIDEC staph" reagent since it is an easy-to-use, reliable technique for the rapid identification of Staphylococcus aureus.

Agglutination Tests↗
PubMed1979

Growth agglutination and growth inhibition tests in the diagnosis of brucellosis.

Growth agglutination and growth inhibition tests were established for the diagnosis of Brucella abortus infection. The former involves the agglutination of living organisms while the latter is a bactericidal test. Using mouse, guinea-pig, rabbit and bovine serum it was shown that the growth agglutination test is approximately ten times, and the growth inhibition test one hundred times, more sensitive than the conventional tube agglutination test. It is suggested that these techniques may be of assistance in diagnosing bovine brucellosis in situations in which the tube agglutination test results are suspected of being falsely negative.

Agglutination Tests↗
PubMed1982

Cholera toxin mediated agglutination of ganglioside Gm1 containing phospholipid vesicles and Gm1-coated polystyrene spheres.

Quasi-elastic laser light scattering is used to examine the cholera toxin mediated agglutination of ganglioside GM1 containing phospholipid vesicles and Gm1-coated polystyrene spheres. We find that the ability of cholera toxin to agglutinate Gm1-containing phospholipid vesicles depends markedly on the lipid composition of the vesicle, with only those composed of short-chain lipids (C14, C16) being appreciably agglutinated. This is interpreted as due to poor mixing of these lipids with the longer chain gangliosides, resulting in lateral separation of the gangliosides in the membrane bilayer. A simple quantitative model, a modification of that developed by von Schulthess et al. [von Schulthess, G. K., Cohen, R. J., Sakato, N., & Benedek, G. B. (1976a) Immunochemistry 13, 955--962], is developed to describe these agglutination processes. Application of this model to the agglutination of Gm1-coated polystyrene spheres by cholera toxin allows an estimate of a minimum value of 4.5 x 10(4) M-1 for the association constant of cholera toxin for its initial Gm1 receptor.

Agglutination↗
PubMed1974

Galactosyltransferase and concanavalin A agglutination of cells.

A correlation has been observed between concanavalin A agglutination of various cell types and the presence of surface membrane galactosyltransferase (1-O-alpha-D-Galactosyl-myo-inositol:raffinose galactosyltransferase, EC 2.4.1.67) activity. Moreover, a reduction to less than 50% of cell surface galactosyltransferase activity occurred after treatment with concanavalin A; other cell surface glycosyltransferase enzyme activities examined were unaffected by concanavalin A treatment. To confirm the participation of cell surface galactosyltransferase in concanavalin A-induced cell agglutination, the enzyme from rabbit erythrocytes was solubilized by sonication and purified by preparative polyacrylamide gel electrophoresis. It was possible to achieve a purified preparation of rabbit erythrocyte galactosyltransferase by separation on concanavalin A-Sepharose. The purified enzyme showed visible immunoprecipitation (Ouchterlony) with concanavalin A. Furthermore, human erythrocytes, which are not normally agglutinated by concanavalin A, became agglutinable by the lectin when the erythrocytes were preincubated with purified galactosyltransferase. These experiments suggest a direct and possible specific role of cell surface galactosyltransferase enzyme in the mechanism of concanavalin A agglutination of cells.

Agglutination↗
PubMed1958

Immunoreactions involving platelets. III. Quantitative aspects of platelet agglutination, inhibition of clot retraction, and other reactions caused by the antibody of quinidine purpura.

Quantitative aspects of platelet agglutination and inhibition of clot retraction by the antibody of quinidine purpura were described. The reactions appeared to depend on formation of types of antibody-quinidine-platelet complexes which could fix complement but complement was not necessary for these reactions. Complement fixation was at least 10 times more sensitive than platelet agglutination or inhibition of clot retraction for measurement and detection of antibody activity. Although it has been considered that antibodies of drug purpura act as platelet lysins in the presence of complement and that direct lysis of platelets accounts for development of thrombocytopenia in drug purpura, the present study suggests that attachment of antibody produces a change in platelets which is manifested in vitro only by increased susceptibility to non-specific factors which can alter the stability of platelets in the absence of antibody. The attachment of antibody to platelets in vivo may only indirectly affect platelet survival. In contrast to human platelets, dog, rabbit, and guinea pig platelets, and normal or trypsin-treated human red cells did not agglutinate, fix complement, or adsorb antibody; and intact human endothelial cells did not fix complement or adsorb antibody. Rhesus monkey platelets were not agglutinated by the antibody but did adsorb antibody and fix complement although their activity in these reactions differed quantitatively from that of human platelets. Cinchonine could be substituted for quinidine in agglutination and inhibition of clot retraction reactions but quinine and cinchonidine could not. Attempts to cause passive anaphylaxis in guinea pigs with the antibody of quinidine purpura were not successful.

Agglutination↗
PubMed1976

Agglutination with O antisera of salmonella exposed to antibiotics.

Five strains of Salmonella were grown on agar containing subinhibitory concentrations of ampicillin, gentamicin, tetracycline, or chloramphenicol, and on drug-free agar (control). Antigens were prepared by heating bacteria suspensions in saline solution at 100 C or by suspension in alcohol. Antigens were tested for agglutinability with somatic O antisera and fluorescent antibody staining. The alcohol-treated antigens prepared from organisms grown in the presence of antibiotics other than ampicillin had lower agglutination titers than did the control grown on drug-free agar. Heat-treated control antigens had lower agglutination titers than did the alcohol-treated control antigens. The agglutinability of heat-treated antigens prepared from organisms that had been exposed to antibiotics was preserved or enhanced. The agglutinated filaments produced a flocculent sediment, in contrast to the granular sediment of the controls. No significant morphologic abnormality in cell-wall structures of antibiotic-exposed cells could be detected by either electron microscopy or the fluorescent antibody staining.

Agglutination Tests↗
PubMed1975

Agglutination of 2,4-dinitrophenyl-tagged normal human leukocytes by concanavalin A: possible relationship to their ability to evoke production of leukemia-associated antibodies.

Normal peripheral blood leukocytes were tagged with 2, 4-dinitrofluorobenzene at a ratio of 10-11 molecules/cell. One-tenth ml of various concentrations of concanavalin A (Con A) was added to 0.2 ml of either tagged or untagged cells (5 times 10-6/ml) and incubated for 20 minutes at ambient temperature, after which agglutination was scored visually. A readily discernible quantitative difference in the agglutinability of 2, 4-dinitrophenyl (DNP)-tagged versus untagged cells was seen at all concentrations of Con A in the range of 12.5 800 mug/ml. The reaction was maximal at 24 degrees C, somewhat diminished at 37 degrees C, and minimal at 4 degrees C. The agglutination of DNP-tagged leukocytes by 50 mug Con A/ml was completely blocked with 0.1 M methyl-alpha-D-glucopyranoside (alpha-MG), but as low a concentration as 0.001 M alpha-MG inhibited agglutination of untagged cells. The ability of Con A to agglutinate DNP-tagged normal leukocutes may be attributed to a lowering of the zeta potential, a topographic rearrangement of receptor sites, or the formation of new antigenic determinants similar to those found on malignant cells. The last alternative would be consistent with the observation that DNP-tagged normal leukocytes could evoke the production of antibodies that reacted with leukemic granulocytes.

Agglutination↗
PubMed1997

Contraceptive effect of sperm-agglutinating monoclonal antibodies in rabbits.

Immune infertility in humans correlates clinically with the presence of anti-sperm antibodies that trap (agglutinate) sperm in semen and cervical mucus. To test whether sperm-agglutinating antibodies can be effective contraceptive agents, several mouse anti-rabbit sperm (MARS) sperm-agglutinating monoclonal antibodies (mAbs) were developed that rapidly and completely agglutinate sperm: MARS-M3 (IgM), MARS-G16 (IgG3), and MARS-G17 (IgG3). Contraceptive efficacy of these mAbs was tested by mixing the mAb with 0.1 ml semen (approximately 1/5 of a whole ejaculate) immediately before artificially inseminating rabbits paracervically. This paracervical dose of semen provided a rigorous test since it delivered several thousand times more fertilizing doses than does a human ejaculate. All of the mAbs were contraceptively effective, and MARS-G16 reduced the number of fetuses per animal by 88% and 95% with doses of 150 microg and 2 mg, respectively. The contraceptive efficacy of the MARS mAbs in the rabbit suggests that human sperm-agglutinating mAbs may be effective agents for vaginal contraception in humans.

Animals↗
PubMed1997

Biochemical characterization of sperm agglutination antigen-1, a human sperm surface antigen implicated in gamete interactions.

The anti-sperm monoclonal antibody (mAb) S19 was previously demonstrated to agglutinate human spermatozoa, inhibit sperm penetration of cervical mucus, and inhibit sperm-zona pellucida binding. These results implicated the cognate S19 antigen, designated sperm agglutination antigen-1 (SAGA-1), in gamete interactions and identified SAGA-1 as an attractive candidate for immunocontraceptive development. In the present study, evaluation of sperm agglutination with video microscopy showed that the S19 mAb rapidly and completely agglutinated human spermatozoa in a "tangled" pattern of agglutination. One- and two-dimensional immunoblot analyses identified SAGA-1 as a highly acidic, polymorphic sperm protein with an apparent molecular mass of 15-25 kDa and an isoelectric point of 2.5-3.0. Periodate treatment abolished this immunoreactivity, demonstrating that the S19 mAb reacted with a carbohydrate epitope and indicating that SAGA-1 is a glycoprotein. Absence of S19 immunoreactivity in postvasectomy seminal fluid implicated the testis, epididymis, and/or proximal vas deferens in the expression of SAGA-1. In solubility and phase partitioning assays, SAGA-1 was extracted from spermatozoa in Triton X-114 and exhibited the hydrophobic characteristics of integral and glycosylphosphatidyl inositol-anchored membrane proteins. These results identify SAGA-1 as a hydrophobic, highly acidic sperm glycoprotein that is localized on the entire sperm surface and has potential significance as a target for antibodies that inhibit sperm function and gamete interactions.

Antibodies, Monoclonal↗
PubMed1981

Agglutination, toxigenicity and sorbitol fermentation of Clostridium difficile.

A total of 79 Clostridium difficile strains from different sources (50 strains from the fecal specimens of healthy adults, 13 from patients receiving antibiotics without gastrointestinal complications, 13 from antibiotic-associated pseudomembranous colitis (PMC) or diarrhea patients, and three strains from ATCC) were investigated for agglutinability, using formol-treated cells as antigen, in relation to toxigenicity. C. difficile strains tested were divided into four serovars, I, II, III, and IV, by the cross-agglutination test. The agglutinin absorption test revealed that strains of serovar I, agglutinable with high titers (5,120-10,240) to antiserum prepared against a highly toxigenic C. difficile strain, ATCC 17859, possessed the serovar-specific antigen. All of the strains of serovar I were highly toxigenic and all 13 strains isolated from the fecal specimens of antibiotic-associated PMC or diarrhea patients belonged to this serovar, whereas 19 (38%) out of 50 strains from healthy adults and four (30.8%) out of 13 strains from patients receiving antibiotics without gastrointestinal complications possessed this antigen. None of the strains of other clostridial species than C. difficile were agglutinated by the three reference antisera used. Further study on the sugar fermentation test disclosed that sorbitol-fermenting property of C. difficile if very closely related to the toxigenicity and agglutinability.

Agglutination Tests↗
PubMed2005

The role of RhD agglutination for the detection of weak D red cells by anti-D flow cytometry.

Anti-D flow cytometry is an accurate method for quantifying feto-maternal haemorrhage (FMH). However, weak D red cells with <1000 RhD sites are not detectable using this methodology but are immunogenic. As quantitation of RhD sites is not practical, an alternative approach is required to identify those weak D fetal red cells where anti-D flow cytometry is inappropriate. We describe a simple algorithm based on RhD agglutination and flow cytometry peak separation. All weak D (n = 34) gave weak agglutination with RUM-1 on immediate spin (grading </=2.5). In Diamed-ID Diaclon ABO/D or ABO/Rh for Newborn cards two subgroups of weak D were observed. In one subgroup, weak agglutination (grading 3) was observed and the red cells were undetectable by flow cytometry. In the second subgroup, agglutination was strong (grading 4) and the red cells were detectable by anti-D flow cytometry. The accuracy of the quantitation was dependent on adequate separation of the weak D and RhD-negative peaks as in seven of 11 samples <1.11% of an expected 2% red cells were detectable. Monitoring RhD agglutination and flow cytometric peak separation are pivotal if anti-D flow cytometry is to be maintained as the primary technique for FMH quantitation in the routine laboratory.

Agglutination Tests↗
PubMed1979

Kinetics of the agglutination of IgG-coated latex particles by C1q: the influence of heat-labile serum components.

Interaction between human C1q and IgG coated latex particles has been studied by means of a standard aggregometer equipment. A dose-dependent agglutination was observed and 100 ng of C1q were readily detected. The kinetics of the agglutination was also monitored. Serum, partially purified C1, and high molecular weight fractions from Sephadex G-200 fractionated serum produced agglutination only in the presence of EDTA. In the absence of this chelator these products disintegrated preformed C1q-IgG-latex particle agglutinates. This disagglutinating principle is heat-sensitive and tentatively macromolecular C1 dependent. The most probable basis of the activity is the competition between C1, with a high affinity for IgG particles, and C1q. The inability of C1 to induce particle agglutination might be caused by the C1 subunits C1r and C1s sterically inhibiting the subunit C1q to bridge between the particles.

Agglutination↗
PubMed1993

Assessment of circulating agglutinating anti-sperm antibodies in buffalo cows with unexplained infertility and an attempt to identify buffalo sperm isoantigens.

The presence of circulating agglutinating anti-sperm antibodies as cause for unexplained infertility of artificially inseminated buffalo cows was assessed. An attempt to identify buffalo sperm isoantigens was also made. The following methods were applied for that purpose: the tray agglutination test (TAT), SDS-polyacrylamide gel electrophoresis, and immunoblotting. The results obtained showed that three of 90 sera from buffalo cows with unexplained infertility were positive in TAT (3.3%) and their titers were low. A total of 27 spermatozoal polypeptides reacted positively with the IgG-isoantibodies of one of the sperm agglutinating sera in immunoblotting. Of the control sera 12 also revealed individual variations in the number of positive fractions on the blots. On the basis of comparing the blot with the positive sperm agglutinating serum to the blots of the positive controls, two buffalo sperm isoantigens were identified, with the respective molecular weights of 40 kDa and 120 kDa. In conclusion, circulating agglutinating anti-sperm antibodies are very rarely detected in buffalo cows with unexplained infertility after several artificial inseminations.

Agglutination Tests↗
PubMed1976

Identification of Neisseria gonorrhoeae in cultures from tonsillo-pharyngeal specimens by means of a slide co-agglutination test (Phadebact Gonococcus Test).

A slide co-agglutination test (Phadebact Gonococcus Test) for the serological identification of Neisseria gonorrhoeae was assessed on gonococcal-like, oxidase positive colonies from 120 cultures, originating from about 6,500 consecutive tonsillo-pharyngeal specimens received at the Neisseria Department, Statens Seruminstitut. The test was performed after subculture on a serum-free medium, since this procedure was found to reduce the number of strains showing inconclusive reactions (pseudo co-agglutination). If this pseudo co-agglutination does occur, however, the test can be repeated with the addition of trypsin to the test system. This causes the previously inconclusive reactions to be reverted to clearly positive reactions in the case of gonococci, and to clearly negative reactions in more than half of the previously inconclusive reactions with other bacterial strains. The results obtained by the Phadebact Gonococcus Test were compared with those obtained by bacteriological identification procedures. Fifty-six of the 120 cultures examined contained gonococci, and all strains were identified by the slide co-agglutination test (five strains with the addition of trypsin). The remaining 64 cultures were negative or exhibited consistently pseudo co-agglutination (eight strains). The specificity and sensitivity of the reagent was further confirmed by the examination of 53 strains of Neisseria gonorrhoeae and 50 strains representing Neisseria species commonly occurring in tonsillo-pharyngeal specimens. The Phadebact Gonococcus Test was considered to be a reliable alternative to routine bacteriological identification of Neisseria gonorrhoeae.

Agglutination Tests↗
PubMed1999

Comparison of a competitive inhibition ELISA and the card agglutination test for detection of antibodies to Anaplasma marginale and Anaplasma centrale in cattle.

OBJECTIVE: To compare a recently developed recombinant MSP-5 competitive inhibition ELISA with a card agglutination test for detection of antibodies to Anaplasma marginale and Anaplasma centrale in Australian cattle. MATERIALS AND METHODS: The ELISA was compared with the card agglutination test using 208 sera from cattle in Anaplasma-free herds, 86 sera from cattle experimentally infected with A marginale or A centrale and 757 sera from cattle in areas endemic for A marginale. RESULTS: The specificity of the ELISA, based on testing 208 sera from cattle in Anaplasma-free areas, was 99.5%, and the sensitivities for detection of antibodies to A marginale and A centrale in sera from the experimentally infected cattle were 98.0% and 100%, respectively. For the same sets of sera, the specificity of the card agglutination test was 98.6% and the sensitivities for detection of antibodies to A marginale and A centrale were 98.0% and 100%, respectively. For the 757 sera collected from cattle in areas endemic for A marginale, the agreement between the ELISA and the card agglutination test depended on the positive threshold selected for the ELISA. The maximum achievable agreement was 91.5% (kappa = 0.73; 95% confidence interval 0.66, 0.79). CONCLUSION: We conclude that the competitive inhibition ELISA is a useful alternative to the card agglutination test for detection of A marginale or A centrale infection in cattle. The assay should be particularly useful for epidemiological applications such as prevalence studies and control programs.

Agglutination Tests↗
PubMed1989

Occurrence and characteristics of agglutination of Vibrio cholerae by serum from the eastern oyster, Crassostrea virginica.

Cell-free hemolymph (serum) of the eastern oyster, Crassostrea virginica, agglutinated Vibrio cholerae, including all O1 serovars and biovars. Seventy-nine other strains of bacteria, including 14 genera and 26 species, were not agglutinated. The A, B, and C factors of O1 antigen were not involved in agglutination. Bacterial agglutinating (BA) activity was demonstrated for oysters inhabiting different environments of the U.S. Atlantic and Gulf coasts. Oyster serum BA titers showed high individual variation. The serum component(s) involved in BA was inhibited by 80 degrees C heat, pronase, EDTA, mucin, and fetuin treatments. N-Acetylneuraminic acid (10 mg/ml) weakly inhibited BA activity. Ligands of V. cholerae were sensitive to neuraminidase and resistant to 80 degrees C and pronase. High salinities (24 and 30%) enhanced BA. Cross-adsorption tests with V. cholerae and human O+ erythrocytes indicated that BA and hemagglutinating activities may involve different serum components. These results imply that the ecology of V. cholerae in C. virginica is influenced by agglutinating activity of oyster serum.

Agglutination↗
PubMed1981

Sexual agglutination in Saccharomyces cerevisiae.

Treatment of either mating type of Saccharomyces cerevisiae with the appropriate sex pheromone increased cell-cell binding in a modified cocentrifugation assay. Constitutive agglutination of haploids was qualitatively similar to pheromone-induced agglutination. Regardless of exposure to pheromone, agglutinable combinations of cells exhibited maximal binding across similar ranges of ionic strength, pH, and temperature. Binding of all combinations was inhibited by 8 M urea, 1 M pyridine, or 0.05% sodium dodecyl sulfate. From alpha-cells we solubilized and partially purified an inhibitor of a-cell agglutinability. This inhibitor reversibly masked all a-cell adhesion sites and inactivated pheromone-treated and control cells with similar kinetics. The inhibitor behaved as a homogeneous species in heat inactivation experiments. Based on these results, we proposed a model for pheromone effects on agglutination in S. cerevisiae.

Agglutination↗
PubMed1982

A surface polysaccharide of Escherichia coli O111 contains O-antigen and inhibits agglutination of cells by O-antiserum.

The repeating pentasaccharide of O-antigen from Escherichia coli O111 contains galactose, glucose, N-acetylglucosamine, and colitose, the latter representing the major antigenic determinant. Phenol extraction of this strain was previously shown to release two fractions (I and II) containing O-antigen carbohydrate, and both fractions were believed to be lipopolysaccharide. We have now characterized fractions I and II and conclude that only fraction II represents lipopolysaccharide. Fraction II contains phosphate, 2-keto-3-deoxyoctonate, beta-hydroxymyristic acid, and potent endotoxin activity, whereas fraction I was deficient in all of these properties of the lipid A and core oligosaccharide regions of lipopolysaccharide. Fractions I and II each represented 50% of the total cellular O-antigen, and both were present on the cell surface. Both fractions were metabolically stable, and no precursor-product relationship existed between them. Fraction II had a number-average molecular weight of 15,800, corresponding to an average of 12 O-antigen repeats per molecule. In contrast, fraction I had a number-average molecular weight of 354,000, corresponding to an average of 404 O-antigen repeats per molecule. Before heat treatment, cells of E. coli O111 are poorly agglutinated by O-serum; although this indicates the presence of a capsule, the corresponding K-antigen was never detected. We conclude that fraction I, when present on the cell surface, inhibits agglutination of unheated cultures of E. coli O111 by O-serum because: (i) a variant strain which lacks fraction I was agglutinated by O-serum without prior heating; (ii) erythrocytes coated with purified fraction I behaved like bacteria containing fraction I in showing inhibition of O-serum agglutination; and (iii) heat treatment released fraction I and rendered bacterial cells agglutinable in O-serum.

Agglutination↗