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PubMed1988

Sensitivity and specificity of latex agglutination tests used to identify Streptococcus agalactiae and Staphylococcus aureus isolated from bulk tank milk.

Comparisons were made among rapid latex agglutination tests and conventional biochemical tests used to identify Streptococcus agalactiae and Staphylococcus aureus. Ninety-eight streptococci and 149 staphylococci isolated from bulk tank milk were tested. Sensitivity and specificity for the latex agglutination test used for identification of Str agalactiae were 97.6 and 98.2%, respectively. Sensitivity and specificity for the latex agglutination test used for identification of S aureus were 90.2 and 67.5%, respectively. Of 25 staphylococci considered false-positive by the latex agglutination test, 14 (56%) were considered tube coagulase-positive. Fifteen staphylococci considered false-positive by latex agglutination test had biotypes representative of S hyicus of S xylosus.

Animals↗

PubMed1986

Detection of anti-laminin antibodies in sera by latex agglutination.

We describe a latex particle agglutination assay for detecting circulating antibodies against laminin, a noncollagenous glycoprotein of basement membranes. Polystyrene latex particles on which laminin has been adsorbed are incubated with serum for about 25 min at 42-45 degrees C. The agglutination is then measured by counting residual unagglutinated particles. Polyethylene glycol 6000 enhances the agglutination. The assay is fully automated, yielding results in about 45 min, for 50 samples per hour. Addition of purified laminin abolishes the agglutination of laminin-coated particles in practically all positive sera. The anti-laminin antibody titers obtained by this latex immunoassay and by radioimmunoassay correlated well in 161 sera from patients with suspected or established renal diseases. The agglutination assay more frequently gave positive results for cases of glomerulonephritis with linear deposits (20/22 cases) than for glomerulonephritis with granular deposits (7/68) or glomerulonephritis with no glomerular deposits (2/13). The finding of low anti-laminin antibody titers in sera from about 15% (34/230) of the healthy subjects suggests that these autoantibodies are pathogenic only in certain circumstances.

Animals↗

PubMed1986

[Neutrophil agglutination test in sensitized guinea pigs].

Guinea pigs sensitized with DNCB, K2Cr2O7, epidian 5, hardener Z1 and dye B, in which epidermal tests confirmed sensitization, exhibited, 24 hours after the test termination, increased agglutination of neutrophils. In the blood of animals sensitized with dye B using the Polak and Türk, as well as Magnusson and Kligman techniques, percentage indices of agglutination, whether spontaneous or induced by adding 25 micrograms of the allergen, were 2,40 and 8,90 for DNCB, 6,72 and 13.30 for K2Cr2O7, 7.61 and 12.59 for epidian 5, 8.69 and 11.63 for hardener Z1, 1.38 and 2.15 and 2.17 and 3.21 for dye B. The average (from 6 control groups) number of neutrophils, both those self-agglutinated and those induced by allergen, was 2.54 and 3.24, respectively. No increase in neutrophils agglutination in guinea pigs sensitized with the Alekseeva and Sumska technique-exhibiting no allergy--was found. The results point to the usability of determinations of neutrophils agglutination in blood as an auxiliary index confirming sensitivity to a given allergen.

Animals↗

PubMed1977

[Isolation and characterization of mistletoe extracts (Viscum album L.). II. Effect of agglutinating and cytotoxic fractions on mouse ascites tumor cells].

Lectin from mistletoe (Viscum album L.) was studied for its relations with the toxins from Viscum album, ascites tumor cells of mouse, and human immunoglobulins. Using affinity chromatography on glutaraldehyde-crosslinked IgG (human) from viscum crude extract, a fraction was isolated which exhibited full agglutination capacity and high toxicity. The supernatant showed no agglutination capacity but a strong toxic effect on mouse ascites tumor cells. This toxic effect could not be influenced by further additions of insolubilized IgG. Chromatography on DEAE cellulose also gave agglutinating fractions with toxic effects and a non-agglutinating toxic portion. Column chromatography on Sephadex G 75 allowed separation of toxic from agglutinating components. The molecular weight of the toxin remaining after lectin removal was above 10,000. Lectin was found to bind more readily to mouse ascites tumor cells than to erythrocytes.

Animals↗

PubMed1982

The agglutination of human platelets by bovine factor VIII: R.

The binding of bovine factor VIII: R to human platelets causes an agglutination of the platelets and subsequent responses that may serve as a model for the interaction of platelets with damaged vascular subendothelium. Purified bovine factor VIII: R was radiolabeled and its binding to formalin-fixed human platelets measured. Binding was rapid and readily reversible. At saturation, approximately 6 micrograms of factor VIII: R was bound per 10(9) platelets. Optimal agglutination of platelets by bovine factor VIII: R occurred in the pH range of 6.5 to 7.5, although binding was more extensive at lower pH. The isoelectric point of factor VIII: R was 4.3, indicating that it has a net negative charge at physiological pH. Binding and agglutination were both inhibited by increasing the ionic strength of the medium and by polycations like Polybrene and polylysine. Ristocetin promoted the binding of bovine factor VIII: R to platelets but did not promote the agglutination of platelets by bovine factor VIII: R. Concentrations of dextran sulfate that strongly inhibited agglutination actually increased the binding of factor VIII: R to platelets.

Animals↗

PubMed1980

[Ability of vancomycin-group antibiotics to induce or to inhibit thrombocyte agglutination].

The effect of 4 vancomycin antibiotics on factor VIII-dependent agglutination of thrombocytes was studied. Significant similarity, both quantitative and qualitative, between ristocetin and ristomycin was found. In this connection ristomycin may be used for determination of the so-called ristocetin cofactor. Actinoidin and vancomycin inhibited agglutination of platelets induced by ristocetin or ristomycin in platelet-enriched plasma with citrate or EDTA the same as in the system contaning platelets treated with formalin and did not inhibit agglutination induced by the bovine factor VIII. The 4 antibiotics induced precipitation of the plasma protein. Vancomycin was most active and actinoidin ws lest active in this respect. Ristocetin and ristomycin also possessed such capacity, the effect of the latter being higher. Actinoidin and vancomycin did not prevent the immediate effect of light absorption increasing due to addition of ristocetin or ristomycin to fixed platelets in concentrations completely inhibiting agglutination of platelets in the presence of the protein cofactor. Inhibition of this direct effect of ristocetin and ristomycin was observd only at higher concentrations, which indicated that this effect was not probably associated with agglutination. The results of the study on various ristomycin derivatives showed that methylated carboxylic groups and free hydroxyls of phenol may play the main role in ristomycin binding with the thrombocytic membrane and/or protein cofactor.

Dose-Response Relationship, Drug↗

PubMed1984

Fibronectin-induced agglutination of Staphylococcus aureus correlates with invasiveness.

Studies on the interactions of staphylococci with fibrinogen, fibrin split products, and prothrombin have formed the basis for the clumping tests for coagulase and fibrin degradation products. We investigated the role of another circulating protein, fibronectin, in clumping Staphylococcus aureus. Fibronectin is a dimeric glycoprotein with high molecular weight that is present in both blood and tissue and is involved in opsonization, clotting, healing of wounds, cell-to-cell attachment, and differentiation. Each fibronectin molecule has two S. aureus binding sites, thus allowing lattice formation. We defined conditions under which fibronectin will cause agglutination of S. aureus. Strains of S. aureus that were most easily clumped had the largest number of fibronectin receptors. Trypsinization or gentle sonication removed the fibronectin binding and agglutinating receptors from S. aureus. These treatments did not alter viability, which suggests that binding is a superficial component of the organisms. Invasive fibronectin-binding strains were from a wide variety of phage types. Twenty two S. aureus isolates from patients with invasive disease were more readily agglutinated and had a greater number of fibronectin binding sites than 19 noninvasive strains (p less than 2.5 X 10(-4)). This suggests that the pathogenicity of S. aureus invasion may be enhanced by binding of bacteria to tissue fibronectin or by agglutination of bacteria by plasma fibronectin. Thus, the fibronectin receptors on S. aureus that mediate agglutination might also permit invasion of host tissues.

Fibrinogen↗

PubMed1980

Changes in lectin-mediated agglutinability during primary embryonic induction in the amphibian embryo.

The present study was undertaken to investigate structural alterations at the surface of presumptive neural cells after primary embryonic induction. For this purpose, plant lectin-mediated agglutinability of dissociated cells from the epiblast of Bufo arenarum gastrulae was tested. Two fragments of epiblast were excised from the same mid-gastrula: one from the dorsal side of the egg, making contact with the invaginating chordamesoblast and assumed to be composed of determined cells and the other from the ventral region of the egg, facing the blastocoele cavity and assumed to be composed of undetermined cells. Cells of the pooled fragments were dissociated in calcium-free Holtfreter's solution with potassium oxalate and incubated in the presence of different concentrations of phytohemagglutinin and concanavalin A. Epiblast cells overlying the archenteron roof are less agglutinated with both lectins than undetermined cells. On the other hand, when egg fragments were removed from the dorsal and ventral regions of early gastrulae before the archenteron was formed, no significant difference in lectin-mediated agglutinability was observed, even after having been cultured in vitro in absence of inducing tissue. These results suggest that the target of the inducing signal generated in the mesoblast is likely to be located on the surface of epiblast cells. Additional experiments showed that cells pretreated with colchicine, cytochalasin B or colchicine and cytochalasin B simultaneously exhibit no significant variation in agglutinability, suggesting that the cytoskeleton was not be involved in the cell surface alteration here described. Treatment of whole embryos or sandwich explants with concanavalin A or phytohemagglutinin has no effect on neural tube formation, suggesting that the carbohydrate-containing binding sites for these lectins are not involved in primary embryonic induction. Changes in cell agglutinability described in this paper are to be interpreted thus as a secondary expression of structural alterations in the cell surface concomitant with neural determination.

Animals↗

PubMed1981

Detection of cell surface immunoglobulin on leucocytes by agglutination.

The detection of immunoglobulin (Ig) on murine peritoneal cell (PC) surfaces by an agglutination test is described. Addition of anti-mouse IgG (amIgG) to a suspension of PC results in agglutination of the cells. Trypsin or pronase treatment of the cells abrogated agglutination upon addition of amIgG. Incubation of washed murine PC with porcine IgG (pIgG) for 30 minutes resulted in agglutination of the cells upon addition of anti-porcine IgG (apIgG) to the cell suspension. This suggests that the heterologous pIgG is also able to bind to the murine cell surface. The implications of these findings are discussed and compared with respect to the agglutination test described herein and other techniques for detection of cytophilic antibody.

Animals↗

PubMed1982

Role of membrane lipids in cold agglutination of human erythrocytes.

The membrane lipid fluidity of normal human erythrocytes was modified by enrichment and depletion in cholesterol, and the expression of I and SP1 antigens was assayed by quantitative hemagglutination from 4 degrees to 24 degrees C by use of a continuous flow system. Below 16 degrees--18 degrees C, cholesterol enrichment increased and cholesterol depletion decreased percent agglutination. As temperatures approached approximately 18 degrees--20 degrees C, differences in agglutination between modified and unmodified erythrocytes became insignificant despite marked differences in lipid fluidity at that temperature. Thus, fluidity changes alone cannot be responsible for the effect of membrane cholesterol on cold agglutination. In an additional study, the temperature dependence of a relative equilibrium association constant, estimated by probit analysis of percent agglutination at various antisera concentrations, was biphasic with a sharp break at 16 degrees C. Our studies are consistent with the hypothesis that I and Sp1 antigens preferentially partition into a lipid domain that forms during lateral phase separation of membrane lipid developing at low temperature. A resulting increase in antigen density would then become responsible for augmented agglutination by specific antibody.

Cholesterol↗

PubMedDate not supplied

Rheologic characterization of vegetal lectins by dissociation of induced erythrocyte agglutinates.

Energy evolved from hemagglutination reaction or spent in dissociating erythrocyte agglutinates has been proved to be an excellent parameter for analyzing cell-cell interactions mediated by bridging molecules such as antibodies or lectins. We developed a new rheo-optical method to estimate the energy of dissociation of red blood cell agglutinates. In a Couette shear field agglutinates can be dissociated until a suspension of monodispersed cells is obtained. Intensity of light backscattered by suspended agglutinates increases during their mechanical dissociation. Variation of backscattered light intensity correlates with the energy spent in the process. The adhesive energy of erythrocyte agglutination induced by lectins has been estimated by applying this method. Two specific lectins (Dolichus Biflorus agglutinin and Ulex Europaeus agglutinin) and a new lectin obtained from Amarantus Cruentus seeds which specificity is unknown were studied. Results obtained in this work for Dolichus Biflorus lectin are comparable with values published by other authors. An asymptotic decrease of adhesive energy was observed when the mechanical dissociation was applied several times on the same sample. Our results suggest that the cell detachment is accompanied by the extraction of membrane receptors. This finding is consistent with results obtained by other authors.

Energy Metabolism↗

PubMed1995

Agglutinating activity of wheat gliadin peptide fractions in coeliac disease.

The K 562 (S) cell agglutinating activity of peptides obtained from in vitro digestion of bread wheat gliadins has been shown to be associated with a small fraction (coded as Fraction C), that can be easily separated by affinity chromatography of the whole digest on a sepharose 6-B-mannan or sepharose 6-B-oligomers of N-acetyl-glucosamine. Although the whole gliadin digests from 12 durum wheat varieties were unable to agglutinate K 562 (S) cells, all these digests were found to contain an active Fraction C. The lack of agglutinating activity of the whole durum wheat gliadin digests has been shown to be associated with the presence in these digests of another peptide fraction (coded as Fraction B) that is eluted much earlier from the sepharose 6-B-mannan column and is able to inhibit the cell agglutinating activity of Fraction C. Such an active Fraction B is not present in bread wheat gliadin peptides, although peptides with the same elution profile as Fraction B have been detected.

Acetylglucosamine↗

PubMed2005

Rapid identification of Mycobacterium species by lectin agglutination.

The purpose of the present study is to explore the possibility that plant lectins can be used for the development of rapid and inexpensive technique for differentiation of mycobacterial species. The method is based on interaction between mycobacteria and lectins as visualized by agglutination in a microtiter plate. We employed 18 mycobacterium species and determined the minimal lectin concentration (MLC) of 23 different lectins. For some of the bacteria as a high as 1000 microg/ml of one or more lectins were required to induce agglutination, while for other strains as low as 1.95 microg/ml of the lectin were needed. A unique pattern of agglutination was observed for each species over a range of 62-1000 microg/ml lectin concentrations. There were little or no variations in MLC within strains (intraspecies) of each of two species tested. In contrast, there were marked interspecies variations in MLC. Analysis of the MLC showed that the highest score of interspecies differences with 23 lectins was obtained at 125 microg/ml lectin concentration. At this concentration it was found that the pattern of agglutinations with only two lectins was sufficient to differentiate mycobacterium species from each other. Because the bacteria-lectin interaction is adaptable to various methods of visualization, our findings may set the stage for developing a rapid and reliable tool to differentiate mycobacterium species.

Agglutination↗

PubMed1987

Studies on cell adhesion and concanavalin A-induced agglutination of Candida albicans after mannan extraction.

Candida albicans cells were treated with alkali and acid to extract preferentially the cell wall alpha-mannan. Cells were recovered at three stages, as extraction proceeded from mild to more extensive: Alk-1, Alk-2 and Alk + Acid. Yeast adhesion to human epithelial cells was then examined with an in-vitro adherence assay. Yeasts from all three stages of extraction adhered in significantly lower numbers to buccal mucosal cells than did unextracted yeasts. Adhesion was as low for Alk-1 cells as for those submitted to more complete mannan extraction. When yeast cells from all three stages were treated with Concanavalin A (Con A), a lectin probe with strong affinity for yeast alpha-mannans, and then subjected to the adherence assay, there was no significant change in adhesion. When yeast agglutinability by Con A was examined in tests with treated and untreated yeast cells, abundant agglutination occurred only with the untreated cells. However, Alk-1 cells, though lacking in adhesive capacity towards mucosal cells, showed significant agglutination. The results suggest that candidal adhesion is mediated by an alkali-soluble, mannan-containing moiety(ies) which appears to be lost early in the extraction process. Blockage of this moiety by Con A inhibits the adhesion of unextracted cells. Extracted cells lack this moiety but still possess enough structural mannan for Con A recognition and agglutination.

Agglutination↗

PubMed1984

Association between infertility following reversal of vasectomy and the presence of sperm agglutinating activity in semen.

A statistically significant association between infertility, following reversal of vasectomy, and the presence of sperm agglutinating activity in post-operative semen samples has been demonstrated in a retrospective study. Sperm agglutinating activity was measured using a microtitration assay, and the number of positive samples rose from 3/78 (4%) pre-operatively, to 34/134 (25%) post-operatively. High titres (greater than or equal to 1:32) of agglutinating activity were observed only when viable sperm were present in the ejaculate. Positive semen titres were obtained only when parallel serum samples were positive at titres of greater than or equal to 1:256. Conception only occurred in the partner of one man whose seminal plasma contained agglutinating activity, but 22/34 (65%) of the men whose semen lacked such activity were fertile.

Female↗

PubMed1974

Dissociation of plaque formation from glucan-induced agglutination in mutants of Streptococcus mutans.

The traits adhesion and cohesion are manifested in Streptococcus mutans by in vitro plaque formation and glucan-mediated agglutination and have been dissociated in mutants of this caries-associated microbe. In these mutants, which differ from each other in colonial morphology, we have observed a consistent loss of ability to form adhesive microbial deposits (plaque) on wires, but only a minimal alteration from the wild type in ability to agglutinate into macroscopic clumps in the presence of exogenous glucans or sucrose. Also, when these mutants were cultured in sucrose-containing medium, there was an increase in the synthesis of water-soluble, extracellular glucans and a decrease in the synthesis of alkali-soluble, cell-associated glucans. Based on these findings, it appears (i) that in vitro plaque formation and agglutination are distinct and dissociable traits, and (ii) that adhesion but not agglutination appears related to the synthesis of alkali-soluble, cell-associated glucans.

Agglutination↗

PubMed1964

SPECIFIC, SOLUBLE FACTOR INVOLVED IN SEXUAL AGGLUTINATION OF THE YEAST HANSENULA WINGEI.

Taylor, Neil W. (Northern Regional Research Laboratory, Peoria, Ill.). Specific, soluble factor involved in sexual agglutination of the yeast Hansenula wingei. J. Bacteriol. 87:863-866. 1964.-A factor was liberated by snail enzymes from unisexual mating type 5 of Hansenula wingei NRRL Y-2340. This factor is the (or a) factor on type 5 involved in sexual agglutination of H. wingei because it agglutinates only the active opposite mating type; it is absorbed appreciably only by the active opposite mating type; and it is inactivated by a mercaptan, the same agent which inactivates sexual agglutination in type 5. The sedimentation rate of the factor, 31 Svedbergs, indicates it to be soluble.

Agglutination↗

PubMed2004

New approach for serological testing for leptospirosis by using detection of leptospira agglutination by flow cytometry light scatter analysis.

Leptospirosis is considered an important reemerging infectious disease worldwide. The standard and most widespread method for the diagnosis of leptospirosis is the microscopic agglutination test (MAT). This test is laborious and time-consuming, and the interpretation of the results is subjective. In the present work we describe an application of flow cytometry (FCM) as a tool for the serological diagnosis of leptospirosis. The analysis is based on the sensitivity of FCM to the size and shape of the bacteria analyzed by measurement of light scatter parameters: forward scatter (FSC) and side scatter (SSC). The addition of positive serum to an infecting leptospiral serovar results in a shift of the light scatter parameter to a different location with higher FSC and SSC values, indicating the formation of leptospiral aggregates. By using immunofluorescent staining, we have shown that the large particles formed are the agglutinated leptospires. Quantification of the agglutination process has been achieved by calculating an agglutination factor (Af), based on changes in the light scatter parameters measured by FCM. Af enables us to determine the specificity of the serological reaction of the patient serum with each leptospiral serovar. In this work, 27 serum samples from 18 leptospirosis patients were tested by both the MAT and the FCM techniques, in which each serum sample was tested against 13 serovars. Twenty-six human serum samples derived from patients with a variety of other defined illnesses were used as negative controls and enabled us to define the Af threshold value as < 9.3 for negative patients, while any value higher than that would be a positive result for leptospirosis. Compared to MAT, the FCM technique was found to be more specific and sensitive, especially in identifying the serogroup in the acute phase of the disease. The whole process was found to be rapid and took less than 1.5 h. Moreover, FCM analysis is objective and can be automated for the handling of large numbers of samples.

Agglutination↗