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At least 19 recordsLinked to original sources
PubMed1984

Analysis and in vivo assay of B. abortus agglutinating and non-agglutinating antibodies.

Studies were made of physicochemical and immunochemical characteristics of Brucella abortus agglutinating and non-agglutinating antibodies in the sera of cattle repeatedly injected with living B. abortus (Strain 1119). Both agglutinating and non-agglutinating antibody were shown to be IgG1, and by immunodiffusion against rabbit anti-cattle gamma-globulin, agglutinating antibody gave a precipitation line of identity with that given by non-agglutinating antibody. Whilst agglutinating antibody increased clearance of antigen from the blood of passively protected mice, non-agglutinating antibody did not enhance clearance. Determination of the spleen infection index in mice pre-treated with agglutinating and non-agglutinating antibody showed that in animals passively immunized with non-agglutinating antibody the number of living (infecting) bacteria was approximately 4 times higher than in the case of agglutinating antibody. The possible potentiation of chronic B. abortus infection by non-agglutinating antibody is discussed.

Agglutination↗
PubMed1979

Lectin-mediated agglutination of murine lymphoma cells. Cell surface deformability and reversibility of agglutination by saccharides.

Agglutination of S49 mouse lymphoma cells by Ricinus communis I agglutinin can be reversed by the competing haptenic saccharide, lactose, soon after agglutination, but after further incubation in the absence of lectin the agglutination reaction could not be reversed by lactose and the cells remained as multicell aggregates. The irreversibility of S49 cell agglutination was time, temperature and lectin concentration dependent and its onset correlated with ultrastructurally observed deformation of adjacent cell surfaces and an increase in the proportion of adjacent cell surface areas in close apposition within multicell aggregates. Pretreatment of S49 cells with cytochalasin B or cytochalasin B plus vinblastine enhanced R. communis I agglutinin-mediated agglutination, while vinblastine alone and fluoride plus azide had essentially no effect. When drug-treated cells were agglutinated and then incubated in lectin-free drug-containing media for various times prior to lactose addition, the drug effects were more pronounced. Cytochalasin B alone or with vinblastine inhibited lactose reversal of S49 cell agglutination compared to the drug-free controls, while fluoride plus azide enhanced hapten reversibility. Electron microscopic analysis revealed that the onset of agglutination irreversibility correlated with cell surface deformation in the drug-treated cells. Cell aggregates that were more readily reversible by lactose (fluoride plus azide) were unchanged or less deformed, while S49 aggregates treated with cytochalasin B plus vinblastine were more deformed compared to controls without drugs. These experiments suggest a role for cell surface deformability as an important secondary effect during lectin-mediated cell agglutination of S49 lymphoma cells.

Agglutination↗
PubMed1987

Concanavalin A-agglutinability of membrane-skeleton-free vesicles and aged cellular remnants derived from human erythrocytes. Is the membrane skeleton required for agglutination?

Vesicles and cell remnants have been obtained by aging of erythrocytes in vitro. The vesicles lacking the membrane skeletal proteins and the remnants known to possess a rigid skeleton have been used to assess the role of membrane skeletal proteins in the process of Con A (concanavalin A)-mediated agglutination of erythrocytes. Both the vesicles and the remnants were found to bind Con A at the same density as did intact cells. The vesicles, isolated from normal as well as from the Con A-agglutinable trypsin- and Pronase-treated cells, failed to agglutinate with Con A. They were, however, well agglutinated by WGA (wheat-germ agglutinin) and RCA [Ricinus communis (castor bean) agglutinin], indicating that the vesicles are not defective in agglutination. Large, cytoskeleton-free, vesicles prepared by another procedure also gave the same results. The aged remnants from trypsin- and Pronase-treated erythrocytes showed significantly decreased agglutination with Con A, but were agglutinated as well as the fresh cells by WGA and RCA. The agglutination with Con A is thus abolished when the membrane skeleton is absent, and reduced when it is rigid, suggesting that the skeleton may play an important role in the agglutination of erythrocytes by Con A.

Concanavalin A↗
PubMed1975

Mating reaction in Saccharomyces cerevisiae. VII. Effect of proteolytic enzymes on sexual agglutinability and isolation of crude sex-specific substances responsible for sexual agglutination.

The effect of proteolytic enzymes on sexual agglutinability of haploid cells of the yeast Saccharomyces cerevisiae was examined. Sexual agglutinability of cells of both a and alpha types was lost on treatment with alkaline protease and two kinds of neutral proteases of Bacillus subtilis, pronase and alpha-chymotrypsin. Agglutinability of alpha type cells was lost after treatment with acid protease of Rhizopus chinensis and trypsin, but that of a type cells was not. These results indicate that the sex-specific substance responsible for the sexual agglutination (agglutination factor) in a type cells differ from that in alpha type cells. Agglutination factors were solubilized from cell-wall fractions of both mating types by Glusalase treatment. These crude factors specifically inhibited the agglutinability of cells of the opposite mating type with little effect on the agglutinability of cells of the same mating type.

Agglutination↗
PubMed1993

Comparative study of staphylococcal co-agglutination and latex agglutination for detection of enterotoxigenic Escherichia coli.

Several biological and immunological methods have been used for detection of ETEC. In this work a comparative study was done between staph-co-agglutination and latex agglutination. From the 75 faecal samples collected from infants and children having acute diarrhea, the total number of E. Coli strains isolated were 64. Out of these 64 strains, 6 strains were found to be positive for Labile Toxin (LT) production by both latex agglutination and staphylococcal co-agglutination test. However, another 3 strains which were negative by latex agglutination were found to be positive by staph co-agglutination test. The latex agglutination test was found to be simple, easy and rapid. However this test was less sensitive in detection of ETEC. The staph-co-agglutination was also found to be simple, easy but it takes longer time (14 days). It was concluded that both tests are simple, inexpensive to perform and can be used for rapid detection of ETEC.

Agglutination Tests↗
PubMed1986

A paradoxical effect of antibody concentration on vWF-dependent platelet agglutination distinguishes between botrocetin and ristocetin-induced agglutination.

Several heterologous antisera directed against either human or porcine von Willebrand factor (vWF), inhibited botrocetin-induced vWF-dependent agglutination at high concentrations but were found to enhance this reaction at low concentrations. Purified IgG from these immune sera also potentiated botrocetin-induced agglutination as did its F(ab)'2 fragments. However, monovalent Fab fragments of the purified IgG did not. The requirement for a divalent antigen combining region suggests that one possible mechanism of enhanced agglutination may involve intra or inter-molecular cross-linking of vWF multimers by the antibody. Another possible mechanism could be a conformational change in the vWF molecule induced by antibody binding. Such a conformational change may provide additional active sites on the vWF molecule that, in the presence of botrocetin, lead to enhancement of the agglutination reaction. Antisera to human vWF that showed this paradoxical inhibitory/enhancing effect on botrocetin-induced agglutination also inhibited ristocetin-induced platelet agglutination at high concentrations, but failed to enhance agglutination at any concentration. The different effects of these antisera on botrocetin and ristocetin-induced platelet agglutination suggest that no single mechanism can explain the action of both of these mediators.

Adjuvants, Immunologic↗
PubMed1978

Latex agglutination, counterimmunoelectrophoresis, and protein A co-agglutination in diagnosis of bacterial meningitis.

Specimens of cerebrospinal fluid from 201 patients with meningitis caused by Neisseria meningitidis groups A/B/C/135, Streptococcus pneumoniae (23 types), and Haemophilus influenzae type b were tested for the presence of specific bacterial antigens by latex agglutination, counterimmunoelectrophoresis (CIE), and protein A co-agglutination. Specific antigens were found in 75% of the specimens by latex agglutination and CIE, and in 60% of the specimens by protein A co-agglutination. Non-specific reactions in protein A co-agglutination were prevented by heating the specimens to 100 degrees C for a few minutes. The three methods are simple and quick to perform. The smallest amount of antiserum was used in protein A co-agglutination, but we found this method less sensitive. Latex agglutination and CIE proved to be equally sensitive, but the first method was easier to adopt in practice.

Agglutination Tests↗
PubMed1980

Sperm immunofluorescence in infertile men: Its relationship with sperm agglutination and gel agglutination.

The spermatozoa from 10 infertile male patients all with sperm agglutination were subjected to direct immunofluorescence using antisera raised against IgA, IgM, and IgG. Sera from these patients were subjected to the Gel Agglutination Test. Although the Gel Agglutination Test related closely with sperm agglutination, none of the spermatozoa from these patients produced a repeatable positive response to direct immunofluorescence. This study suggests that neither sperm agglutination nor the Gel Agglutination Test demonstrate the presence of sperm specific antibodies in the semen of these infertile men.

Agglutination Tests↗
PubMed1975

A quantitative assay for concanavalin A- and Ricinus communis agglutinin-mediated agglutinations of rat ascites hepatoma cells. Relationship between concanavalin A binding and cell agglutination.

A simple quantitative assay method was developed for the agglutination of rat ascites hepatoma cells mediated by Concanavalin A or Ricinus communis agglutinin. This method was based on the principle that the turbidity of a cell suspension is proportional to the sum of the cross-sectional area of cells and aggregatesmas predicted by the theoretical consideration, the turbidity decreased when cells were aggregated and the decrease was a function of the average number of the cells in aggregates. The agglutinability of the cells, judged by this method, showed a maximum value at a certain concentration of the agglutinin. By further addition of the agglutinin, the agglutinability slightly decreased from the maximum. These phenomena were observed both for Concanavalin A and Ricinus communis agglutinin. The binding and the agglutination experiments using [3-H]concanavalin A revealed that the binding to approx;0% of the total receptors caused a maximal agglutination. This suggested that the receptors responsible for the agglutination constitute only a small part of the total receptors on the surface.

Agglutination Tests↗
PubMed1979

Methods for serotyping nasopharyngeal isolates of Haemophilus influenzae: slide agglutination, Quellung reaction, countercurrent immunoelectrophoresis, latex agglutination, and antiserum agar.

Nasopharyngeal isolates of H. influenzae were typed by the slide agglutination test, the Quelling reaction, the latex agglutination test, countercurrent immunoelectrophoresis, and the antiserum agar test. These tests gave essentially comparable results, with countercurrent immunoelectrophoresis and latex agglutination being slightly more sensitive. Cross-reactive problems encountered with latex agglutination and the expense of performing countercurrent immunoelectrophoresis or the antiserum agar test made these tests less practical than the slide agglutination test to identify single strains that were already isolated. The Quellung reaction and slide agglutination were the most rapid tests used to type an organism. For mass screening of multiple samples, countercurrent immunoelectrophoresis was the simplest technique. The antiserum agar test was slow but was the best technique to screen nasopharyngeal swab cultures to identify the presence of any encapsulated strains in the mixed flora. Whether any of the above techniques were as sensitive as the immunofluorescence test was not evaluated in this study.

Agar↗
PubMed1978

An analysis of Con A-mediated agglutination in a Chinese hamster ovary subclone which responds morphologically to growth in dibutyryl cyclic AMP. III. The role of microvilli in the agglutination process.

We have used the H-7w subclone of a Chinese hamster ovary cell line (K1) to investigate the role of cell surface architecture (specifically microvilli, blebs, and sheets) in determining the relative agglutinability of a cell line with Con A. Our evidence clearly demonstrates that no specific, immediately recognizable surface architecture is associated with the agglutinable or non-agglutinable phenotype. Our data suggest that the expression of microvilli on the cell surface is neither necessary to nor sufficient for the phenotype described by enhanced agglutinability with Con A. Furthermore our work demonstrates that cells covered with blebs are as agglutinable as cells covered with microvilli thereby suggesting that the intertwining of microvilli may not be an essential facet of the agglutination phenomenon.

Agglutination↗
PubMed1981

Serotyping of Haemophilus influenzae a comparison of co-agglutination with countercurrent--immunoelectrophoresis and slide--agglutination.

30 out of 55 strains of H. influenzae could be assigned to one of the six serotypes A--F by slide agglutination, countercurrent-immunoelectrophoresis or co-agglutination. While slide-agglutination appeared less reliable due to non-specific agglutinations countercurrent-immunoelectrophoresis was of high specificity. No cross reactions were encountered in this test and results were unambiguously to evaluate. Co-agglutination is attractive because of its rapidity and simplicity without any need of special equipment. It was found to be of increased sensitivity in detecting type B capsular antigen when compared with countercurrent-immunoelectrophoresis, the problem of cross-reactions remains to be solved however. The use of co-agglutination for serotyping H. influenzae strains in combination with countercurrent-immunoelectrophoresis can be recommended.

Agglutination Tests↗
PubMed1989

Electron microscopic study of platelet agglutination induced by thrombotic thrombocytopenic purpura plasma containing 37-KDa platelet agglutinating protein.

It has been demonstrated that plasma from a patient with thrombotic thrombocytopenic purpura (TTP) and 37-KDa platelet-agglutinating protein (PAP p37) purified from the same plasma caused the agglutination of platelets from normal subjects as well as from the same patient after recovery without the requirement of extracellular Ca++ and fibrinogen. Experiments were designed to study the morphologic changes of platelets as a result of agglutination and the distribution of platelet receptors for PAP p37 under transmission electron microscope. Following incubation with TTP plasma or PAP p37 with stirring, platelets showed shape change, pseudopod formation, variable degrees of degranulation, dilatation of open canalicular systems and formation of agglutinates composed of a few to several hundred platelets. After platelets were incubated with TTP plasma or PAP p37 they were washed and further incubated with rabbit anti-PAP p37 serum without stirring followed by immuno-staining. Abundant electron dense reaction products were bound directly and randomly to the outer surface of the membrane of solitary platelets. When the reaction mixture was stirred, electron dense particles were also present between the platelet membranes in the agglutinates. No staining was observed in control experiments using normal plasma or non-immune rabbit serum. These results indicate that the TTP plasma containing PAP p37 causes agglutination, shape change, and variable degrees degranulation in platelets and that PAP p37 binds randomly to the outer surface of platelet membrane.

Blood Platelets↗
PubMed1998

Structural specificities and significance for coeliac disease of wheat gliadin peptides able to agglutinate or to prevent agglutination of K562(S) cells.

Two peptides corresponding to bread wheat A-gliadin fragments 31-43 and 44-55, well known for their ability to damage the coeliac disease intestinal mucosa both in vitro and in vivo, have been confirmed to be very active in inducing in vitro agglutination of K 562 (S) cells. Removal of six amino acid residues from the carboxy-terminal end of the 31-43 peptide, or of five amino acid residues from the amino terminal end of the 44-55 peptide, resulted in a lower, but still very significant, cell agglutination activity. The peptide consisting of ten amino acid residues with a molecular mass of 1157.5 Da, isolated from durum wheat gliadin, was able to prevent agglutination of K 562 (S) cells induced not only by prolamine peptic-tryptic digests from all the cereals toxic in coeliac disease (i.e. bread wheat, rye, barley and oats), but also by the 31-43 and 44-55 peptides. The ability to protect K 562 (S) cells from agglutination was exhibited to the fullest extent also by all the peptides derived from the 1157.5-Da peptide by five progressive deletions of the terminal carboxylic residue, whereas the sixth consecutive deletion yielded a completely inactive peptide. A similar total loss of activity was observed upon addition of a glycine residue to the amino terminal residue of the 1157.5-Da peptide and all the above-mentioned active peptides derived from it. The remarkable sequence homologies existing between peptides able to induce [Gln-Gln-Gln-Pro and -Pro-Ser-Gln-Gln-] or to prevent [H2N-Gln-Gln-Pro-Gln-Asp-COOH] induction of cell agglutination strongly suggest that all these peptides compete for identical or structurally related binding sites on the cell surface.

Agglutination Tests↗
PubMed1973

Agglutination of bacterial spheroplasts: agglutination-dependent degradation of Escherichia coli ribosomal ribonucleic acid.

When Escherichia coli spheroplasts made by ethylenediaminetetraacetic acid and lysozyme were agglutinated by concanavalin A (con A), the degradation of ribosomal ribonucleic acid (rRNA) was found to occur proportionally to the degree of the agglutination, which was determined by microscopic examination or by a newly devised assay based on the slower settling of aggregates. Methyl-alpha-d-glucoside, low temperature or alkaline pH, all of which reverse the agglutination, also reduced the extent of rRNA degradation. This degradation was not due to the direct action of con A since a similar relationship was found in the case of spontaneous agglutination with concentrated spheroplasts in the absence of con A. The possible importance of a change in the cell membrane associated with the agglutination process is discussed in connection with the initiation of rRNA degradation.

Agglutination↗
PubMed1977

Ox erythrocyte agglutinability. 4. The effect of neuraminidase treatment on the agglutinability of cells and ghosts.

1. The inherited differential agglutinability of cattle erythrocytes is shown to be similarly expressed on ghosts and intact cells. 2. Removal of virtually all sialic acid by prolonged neuraminidase treatment does not alter the agglutinability status of ghosts prepared from either high or low agglutinable cells. Hence the differing sialic acid content of the two cell types is not responsible for the differential agglutinability. 3. The significance of these findings with respect to other well defined agglutination systems and current theories of membrane structure is discussed.

Animals↗
PubMed1976

Comparison of the tray agglutination technique with the gelatin agglutination technique for the detection of spermagglutinating activity in human sera.

Extensive comparisons were made between the tray agglutination test (TAT) and the gelatin agglutination test (GAT) in order to evaluate the validity of the TAT for demonstrating spermagglutinating activity in human sera. The incidence of spermagglutination in both tests was about the same. In screening 118 samples from infertile men and women, the TAT seemed to be more sensitive, whereas the reverse was true when 143 samples earlier found positive with the GAT were tested. These differences were mainly encountered with low titers. Two T-agglutinating sera (or 2% of the sera) with a GAT titer of 16 or more (both had a titer of 64) were missed with the TAT. On the other hand, two sera (or 2% of the screened samples) having small H-agglutinates up to a titer of 32 to 64 were positive only with the TAT.

Agglutination Tests↗
PubMed1985

[Interactions between lectins and microorganisms. 1. Determination of the rate of agglutination by measurement of extinction: agglutination of yeast cells (Saccharomyces cerevisiae H155) by concanavalin A].

A simple photometric method for the determination of the agglutination rate of cells by lectins in a continuously stirred suspension is presented. Besides the agglutination rate the method allows the estimation of an average degree of agglutination, i.e. the number of cells per aggregate. The influence of the Con A-concentration, cell number, temperature, and pH on the agglutination rate of Saccharomyces cerevisiae H155 have been studied. The results are of good reproducibility and, therefore, the methods is suitable to describe interactions between cell-bound receptors and receptor-specific proteins, e.g. lectins and antibodies.

Agglutination↗