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PubMed1984

Genes of pyelonephritogenic E. coli required for digalactoside-specific agglutination of human cells.

Most pyelonephritic Escherichia coli strains bind to digalactoside-containing glycolipids on uroepithelial cells. Purified Pap pili (pili associated with pyelonephritis) show the same binding specificity. A non-polar mutation early in the papA pilin gene abolishes formation of Pap pili but does not affect the degree of digalactoside-specific hemagglutination. Three novel pap genes, papE , papF and papG are defined in this report. The papF and papG gene products are both required for digalactoside-specific agglutination by whole bacteria cells as well as for agglutination by pilus preparations. Pili prepared from a papE mutant have lost their binding ability although whole cells from this mutant retain it, implying an adhesin anchoring role for the papE gene product. A mutant with lesions both in the papA and the papE genes does not mediate digalactoside-specific agglutination. The implications of this finding for pilus biogenesis are discussed.

DNA Restriction Enzymes↗

PubMed2003

Influence of spacer length on the agglutination of glycolipid-incorporated liposomes by ConA as model membrane.

Through a systematic investigation of the agglutination of long chain mannolipid and glucolipid incorporated liposomes by concanavalin A (ConA) it was found that the agglutination was dependent on different factors. The studied factors reported here are (1) spacer length and (2) ground lipid matrix. The threshold and the relative saturating ConA binding concentration (saturation point to attain the binding saturation condition) of glycosides with varying spacer length for agglutination are dependent on the spacer length of the glycolipid. These concentrations decrease with the increasing number of in-built ethyleneoxy spacer length in the glycolipid and find its minimum with 6 spacer units; it increases then more and more with increasing number of spacer units (>6 units). This is supposed to be due to the requirement of a proper distance of the hydrophilic determinant from the liposome surface for the response by ConA (response invoking distance), which may be most favorable in case of 6 spacer units. Further increase in number of spacer units (>6) results to an increasing probability of the bending of the spacer chain along with the terminal polar head group more and more towards the liposome surface; this leads to a reduction of the factual distance of the terminal hydrophilic head group from the liposome surface, weakening the response for ConA binding. The threshold concentration or saturation point decreases also with the rigidity of the ground lipid matrix. Increased rigidity of the ground matrix leads to a phase separation and localized 'Domain' formation with the glycolipid inside the ground matrix layer due to their immiscibility, invoking better response resulting to a reduction of required incorporated glycolipid concentration.

Concanavalin A↗

PubMed2001

Hemagglutinin residues of recent human A(H3N2) influenza viruses that contribute to the inability to agglutinate chicken erythrocytes.

To identify the molecular determinants contributing to the inability of recent human influenza A(H3N2) viruses to agglutinate chicken erythrocytes, phenotypic revertants were selected upon passage in eggs or MDCK cells. The Leu194Ile or Val226Ile substitutions were detected in their hemagglutinin (HA) sequence concomitantly with the phenotypic reversion. Remarkably, as little as 3.5% of variants bearing a Val226Ile substitution was found to confer the ability to agglutinate chicken erythrocytes to the virus population. Hemadsorption assays following transient expression of mutated HA proteins showed that the successive Gln226 --> Leu --> Ile --> Val changes observed on natural isolates resulted in a progressive loss of the ability of the HA to bind chicken erythrocytes. The Val226Ile change maintained the preference of the HA for SAalpha2,6Gal over SAalpha2,3Gal and enhanced binding of the HA to alpha2,6Gal receptors present on chicken erythrocytes. In contrast, simultaneous Ser193Arg and Leu194Ile substitutions that were found to confer the ability to agglutinate sheep erythrocytes increased the affinity of the HA for SAalpha2,3Gal.

Amino Acid Substitution↗

PubMed1981

Recessive and dominant genes controlling inducible sexual agglutinability in Saccharomyces cerevisiae.

We have characterized the two dominant genes, IND 1 and IND 2, responsible for inducible sexual agglutinability. The strains carrying these genes differ from the inducible strains carrying the recessive gene, saa 1 in the following points. The former strains produce agglutination substance at 22 degree, 28 degree, and 37 degree C only response to sex pheromone of the opposite mating type, but the latter strains produce the substance constitutively without the pheromone at 22 degree C, only in response to the pheromone at 28 degree C, and do not produce the substance, even in the presence of the pheromone, at 37 degree C. We suggest that strains carrying one of the dominant, inducible genes are wild type and have a pheromone-controlled regulatory system of sexual agglutinability.

Animals↗

PubMedDate not supplied

Evaluation of a rapid latex agglutination test (Directigen) for the direct detection of group A streptococci from throat swabs.

A rapid group A beta-hemolytic streptococci (GAS) antigen detection test using latex agglutination (Directigen, Becton Dickinson) was compared with a conventional culture method for the direct detection of GAS from throat swabs. One throat specimen was collected from each of 229 patients. After standard inoculation onto sheep blood agar plates, all swabs were tested for GAS antigen. Of the 229 specimens tested, 46 (20%) were GAS-positive by culture. Direct latex agglutination agreed with culture in 222 of them (97%). The sensitivity of the test was 93% (43/46), the specificity 98% (179/183), the positive predictive value 91%, and the negative predictive value 98%. The detection of GAS antigen by coagglutination (Phadebact, Pharmacia) was also carried out. 81% (35/43) of the cultures and Directigen-positive specimens gave a positive coagglutination for GAS. 100% (179/179) of the cultures and Directigen-negative specimens were also negative by the coagglutination test. We conclude that the Directigen rapid latex agglutination test for the direct detection of GAS from throat swabs compares favorably with culture and has the advantage of providing same-day results.

Humans↗

PubMed1996

Modified latex agglutination test for rapid detection of Streptococcus pneumoniae and haemophilus influenzae in cerebrospinal fluid and direct serotyping of Streptococcus pneumoniae.

A modified latex agglutination test was designed and evaluated for the rapid detection of Streptococcus pneumoniae and haemophilus influenzae type b capsular antigens, and for direct serotyping of Streptococcus pneumoniae in the cerebrospinal fluid. Reagents were prepared by sensitizing latex particles with Omniserum (against 83 capsular serotypes of pneumococci) and Haemophilus influenzae type b burro antiserum. For serotyping reagents, latex particles were similarly coated with nine pneumococcal pool (a to I) antisera and 46 individual pneumococcal serogroup/serotype specific antisera. The test was performed on cerebrospinal fluid from 298 patients with suspected meningitis. Serotyping was done directly on untreated cerebrospinal fluid samples showing positive reactions with the Omniserum reagent. Pneumococcal or Haemophilus influenzae type b antigens were detected in 41 patients; in 32 of these the etiology was established by culture and in 2 by smear examination. Five of the remaining seven cases were judged clinically and by cytological examination of cerebrospinal fluid to have partially treated bacterial meningitis. In two cases the test was false positive. The overall sensitivity and specificity of the latex agglutination test for the detection of Streptococcus pneumoniae and Haemophilus influenzae type b antigens was 100% and 96.8% respectively. The commonest pneumococcal serotypes were type 1 (30%), types 6 and 19 (10% each). The latex agglutination test is rapid and simple to perform, yielding serotype data directly by testing of cerebrospinal fluid.

Adult↗

PubMed1992

Preparation of latex sensitized with rabbit IgG antibody for slide reversed passive agglutination.

A method is described for preparing latex particles sensitized with IgG antibody (IgG-sensitized latex) applicable to the slide reversed passive agglutination (RPLA) test. Soap-free latex (latex) was sensitized with IgG which had been isolated from rabbit anti-bovine lactoferrin serum using protein A Sepharose CL 4B. Unadsorbed protein-binding sites on the surface of latex were blocked with bovine serum albumin (BSA). IgG-sensitized latex that gave better agglutination in RPLA could be selectively obtained by centrifugation at 19 900g for 15 min in 0.01 mol/L glycine buffer (pH 7.3; specific gravity 1.042) containing 3% NaCl, 5% saccharose and 2% choline chloride. By dispersing this IgG-sensitized latex in 0.01 mol/L glycine buffer (pH 7.3) containing 1-2% BSA, a uniformly suspended, highly reactive, readily agglutinable preparation was obtained.

Adsorption↗

PubMed1989

Evaluation of a rapid latex agglutination test for detection of group B streptococci in vaginal specimens.

A rapid latex agglutination test (Bactigen Group B Streptococcus Cervical Screen) for detection of group B streptococci in cervical-vaginal specimens was evaluated using two different slide systems, the traditional serologic slide and capillary action track (Trak) slide. Culture was used as reference method. A total of 344 cervical-vaginal specimens were tested. The group B streptococci carrier rate was found by culture to be 10.8%, 56.8% of these specimens being heavily colonized. The sensitivity and specificity of the latex agglutination test in heavily colonized specimens was 95.2% and 99.3% for the serologic and track slides respectively. The overall sensitivity, including lightly colonized specimens, was 62.2%. The positive predictive value was 92% for both slide systems, and the negative predictive value 95.4% and 95.6% for the serologic and track slides respectively. The latex agglutination test, used with either slide, provides a rapid and effective method for identification of specimens heavily colonized with group B streptococci. The track slide may provide a convenient alternative to serologic slides since it does not require rotation.

Cervix Uteri↗

PubMed1991

Latex agglutination for rapid identification of methicillin-resistant Staphylococcus aureus recovered from selective media.

The accuracy of combining latex agglutination with selective media for the identification of methicillin-resistant Staphylococcus aureus (MRSA) was determined. Test strains were identified by latex agglutination on blood agar, the heat-stable thermonuclease test and broth microdilution MICs of oxacillin and included 97 MRSA, 56 methicillin-susceptible Staphylococcus aureus, 52 methicillin resistant, and 49 methicillin-susceptible Staphylococcus species. Isolates were grown on trypticase-soy agar with 5% sheep red blood cells (TSAB), Mueller-Hinton agar (MHA), mannitol-salt agar (MSA), and four media designed for the selective growth of MRSA:TSAB with clindamycin and gentamicin, MHA with oxacillin, MSA with oxacillin, and lipovitellin-salt-mannitol agar (LVSM) with 1 microgram oxacillin disks applied. The mean sensitivity, specificity, and positive predictive value for the combination of latex agglutination with selective media for the identification of MRSA was 96%, 99% and 98% respectively.

Culture Media↗

PubMed1983

Latex agglutination test for detection of Candida antigen in patients with disseminated disease.

A latex agglutination test has been devised which allows detection of a circulating antigen in patients with systemic infection due to Candida albicans, Candida tropicalis and Candida parapsilosis. Latex is sensitized with serum from rabbits immunized with whole heat killed Candida albicans blastoconidia. The active component of this serum is IgG. Control latex, used to differentiate non-specific agglutination, is sensitized with the same dilution of serum from a rabbit without antibody to Candida species. Sera from a number of patient groups were tested. While none of the hundred normal controls had an antigen titer of greater than or equal to 1:4, 30 of 33 patients with documented disseminated candida infection had antigen titers of 1:4 to 1:32. Two of the 33 gave false negative results, and one caused nonspecific agglutination. In all patients who recovered after antifungal therapy antigen levels returned to within the range found in normal controls.

Adult↗

PubMed1991

Contact patterns in concanavalin A agglutinated erythrocytes.

Agglutination of human erythrocytes by the lectin concanavalin A is enhanced when the erythrocytes are pretreated with neuraminidase, which removes sialic acids, or with pronase, which degrades both the glycophorins and band 3 protein. In the present work transmission electron microscopy of the enzymatically pretreated erythrocytes shows a regular pattern of interruption of contact between interacting plasma membranes. The lengths characteristic of the pattern were 0.66 and 0.50 microns for pronase- and neuraminidase-pretreated cells, respectively. Agglutination of normal erythrocytes and of neuraminidase-pretreated erythrocytes can be fully reversed by exposure to the competitive inhibitor methyl alpha-D-mannopyranoside. Complete reversal of contact does not occur with pronase-pretreated cells. The comparatively greater tenacity of contact between cells that were treated with pronase before exposure to lectin argues for an involvement of nonspecific interactions in the agglutination process. The results are compared with previously published studies of spatially periodic contact patterns induced by a range of other polymers.

Binding, Competitive↗

PubMed2005

Usefulness of a latex agglutination assay for FDP D-dimer to demonstrate the presence of postmortem blood.

D-dimer, a specific fragment resulting from degradation of cross-linked fibrin, is an essential marker for the diagnosis of disseminated intravascular coagulation (DIC). Rapid assay for D-dimer using monoclonal antibody coated-latex particles might be useful for discriminating between postmortem and antemortem blood in bloodstains. We tried to detect D-dimer in nine postmortem blood samples by the rapid latex agglutination assay and to quantify them automatically using the latex photometric immunoassay system. The results showed that all samples were positive and that their amounts of D-dimer were 335-2,800 microg/ml (the normal blood level, <1 microg/ml; the pathogenic blood level with DIC, 1-100 microg/ml). Next, nine stains made of postmortem blood were examined by the rapid latex agglutination assay. The result showed that only one case (D-dimer 335 microg/ml blood) showed weak positive while the others (D-dimer 600-2,800 microg/ml blood) were positive. The present study indicates that the latex agglutination assay for D-dimer can be useful to demonstrate the presence of postmortem blood.

Adolescent↗

PubMed2003

Use of direct latex agglutination testing of selective broth in the detection of group B strepptococcal carriage in pregnant women.

Direct latex agglutination testing of selective broth medium for the detection of group B streptococci was evaluated. Results were compared with those obtained by the recommended subculture method. Among the 551 vaginal-rectal specimens tested, 101 (18.3%) were positive by the subculture method. Of these subcultures, latex agglutination testing detected 99 (98%) positive specimens. Agglutination testing of selective broth is a sensitive method which offers the advantage of saving 24 h in the turnaround time for detection of group B streptococci in pregnant women.

Adult↗

PubMed1993

A rapid test for abruptio placentae: evaluation of a D-dimer latex agglutination slide test.

OBJECTIVE: Our purpose was to evaluate a rapid latex agglutination slide test for D-dimer, a byproduct of clot lysis, in the prediction of abruptio placentae. STUDY DESIGN: Four groups were studied: (1) 15 patients with normal pregnancies at 40 weeks' gestation, (2) 17 participants with preeclamptic pregnancies, (3) 14 patients with preterm labor, and (4) 15 patients with confirmed abruptio placentae. The latex agglutination slide test was performed with positive and negative reference solutions and plasma dilutions of 1:1, 1:2, 1:4, and 1:8. A test was considered positive if, at 2 minutes, agglutination was present at dilutions of > or = 1:2 (> or = 1.0 micrograms/ml fibrin equivalent units). Test results were compared in patient groups with and without abruptio placentae by means of the chi 2 test. RESULTS: The likelihood of a positive D-dimer test result was not significantly different among patients in the non-abruptio placentae groups (p = 0.454). Patients in the abruptio placentae group were significantly more likely to have a positive D-dimer slide test result than those in the non-abruptio placentae groups (p = 0.0001). The D-dimer test conferred sensitivity, specificity, positive predictive value, and negative predictive value of 67%, 93%, 91%, and 48%, respectively. In contrast, other laboratory measures of coagulation (e.g., platelet count, prothrombin time, partial thromboplastin time, and fibrinogen levels) yielded no better than a 20% sensitivity for abruptio placentae. CONCLUSIONS: The D-dimer slide test may be a superior rapid method to improve early diagnosis of abruptio placentae.

Abruptio Placentae↗

PubMed1976

On the structure of agglutinated sheep red blood cell membranes.

Specimens of isolated sheep red blood cell membranes are prepared by an agglutination technique in which membranes are stacked in regular arrays. X-ray diffraction patterns are recorded from such specimens which show meridional and equatorial diffraction phenomena. The meridional reflections correspond to single lamellar repeat periods of 160-186 A. It is concluded that two asymmetric membranes are contained in the elementary period. Lipid phases with preferentially oriented hydrocarbon chains are part of the membrane structure. The stacking of the membranes is also demonstrated in the electron microscope. The X-ray scattering curve of intracellular hemoglobin of intact sheep red blood cells is recorded to a spacing of about 8 A-1. The broad diffraction rings of this scattering curve are replaced by a series of rather sharp rings, when the red blood cells are agglutinated and placed in a hypertonic medium. Both the presence of a functioning membrane and the agglutination appear to be essential for the full expression of this phenomenon.

Animals↗

PubMed1978

Phytohemagglutinin and transmembrane proteins in agglutinated sheep erythrocyte ghost membranes.

Oriented and periodically stacked sheep erythrocyte ghost membrane specimens were prepared by agglutination of the ghosts with phytohemagglutinin M and sedimentation, and were studied by X-ray diffraction. The spatial orientation of the planes of the membranes in the diffracting stack was determined from the lamellar reflections of the periodic stacking. Equatorial diffraction at (10.5 A)-1 and a (1.5 A)-1 reflection were recorded which correlate with side-to-side packed transmenbrane alpha-helices in the agglutinated membrane. A broad (4.6 A)-1 ring with strong equatorial accentuation and broad maxima at about (2.2 A)-1 and (1.2 A)-1 were observed which are attributed to the hydrocarbon chain arrangement in lipid phases of the agglutinated ghost membrane.

Animals↗

PubMed1980

Cell surface proteoglycans as a negative modulator in concanavalin A-mediated agglutination of hepatoma cells.

Proteoglycan (heparan sulfate-protein conjugate) was solubilized with 8 M urea from rat liver plasma membranes after enzymic (RNAase, neuraminidase) treatments and extensively purified by chromatography and gel filtration. The final products gave an average ratio of hexuronate to protein (weight) of approx. 1.5, contained hexosamine equimolar to hexuronate and were sensitive to beta-elimination (the molecular weight being reduced from 20 . 10(4) to 3 . 10(4) (gel filtration)). The proteoglycan fraction, when added to trypsinized and untrypsinized ascites hepatoma (AH-130F(N)) cells, inhibited the concanavalin A-mediated agglutination of the cells. However, the alkali-treated proteoglycan (beta-elimination) or acid mucopolysaccharide fraction prepared from liver plasma membranes by papain digestion were less effective, and a reference preparation of heparan sulfate was almost ineffective. It was confirmed that significant amounts of proteoglycan labelled with 35SO4(2-) were firmly bound to or taken up by the trypsinized ascites hepatoma cells. These results together with the sensitization of lectin-mediated agglutination by mild protease treatment of cells suggest that cell surface proteoglycans may act as a negative modulator in the lectin-mediated agglutination of cells.

Animals↗

PubMed1977

Failure of anti-gamma 3 antibodies to detect some gamma3 chains by an agglutination inhibition test.

Four of eight anti-gamma3 antibodies that detect gamma3 by double diffusion were found to test for Gm allotypes when they were used in the agglutination inhibition test. One tested for Gm (26), two for Gm (11), and one for both allotypes. So far as the present data show, the remaining four test for a gamma3 isotype in the agglutination inhibition test. We suggest that a sample that is negative by the agglutination inhibition test should be tested by double diffusion before it is concluded that the sample lacks gamma3.

Animals↗