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PubMed2001

Differential Vicia villosa agglutinin reactivity identifies three distinct dystroglycan complexes in skeletal muscle.

We present evidence for the expression of three alpha-dystroglycan glycoforms in skeletal muscle cells, including two minor glycoforms marked by either patent or latent reactivity with the N-acetylgalactosamine-specific lectin Vicia villosa agglutinin. Both minor glycoforms co-isolated with beta-dystroglycan, but not with other dystrophin/utrophin-glycoprotein complex components, suggesting that they may perform distinct or modified cellular functions. We also confirmed that both patent and latent V. villosa agglutinin-reactive alpha-dystroglycan glycoforms are expressed in C2C12 myotubes. However, we found that the combined effect of saturating concentrations of V. villosa agglutinin and laminin-1 were strictly additive with respect to acetylcholine receptor cluster formation in C2C12 myotubes, which suggests that laminin-1 and V. villosa agglutinin do not compete for the same binding site on the cell surface. Finally, although beta-N-acetylhexosaminidase digestion dramatically inhibited agrin-, V. villosa agglutinin-, and laminin-1-induced acetylcholine receptor clustering in C2C12 myotubes, treatment with this enzyme had no effect on the amount of alpha-dystroglycan that was bound to V. villosa agglutinin-agarose. We conclude that alpha-dystroglycan is not the V. villosa agglutinin receptor implicated in acetylcholine receptor cluster formation. However, our data provide new support for the hypothesis that different glycoforms of alpha-dystroglycan may perform distinct functions even within the same cell.

Animals↗
PubMed2000

A CD2-based model of yeast alpha-agglutinin elucidates solution properties and binding characteristics.

We have previously shown that the Saccharomyces cerevisiae cell adhesion protein alpha-agglutinin has sequence characteristics of immunoglobulin-like proteins and have successfully modeled residues 200-325, based on the structure of immunoglobulin variable-type domains. Alignments matching residues 20-200 of alpha-agglutinin with domains I and II of members of the CD2/CD4 subfamily of the immunoglobulin superfamily showed > 80% conservation of key residues despite low sequence similarity overall. Three-dimensional models of two alpha-agglutinin domains constructed on the basis of these alignments were shown to conform to peptide mapping data and biophysical properties of alpha-agglutinin. In addition, the residue volume and surface accessibility characteristics of these models resembled those of the well-packed structures of related proteins. Residue-by-residue analysis showed that packing and accessibility anomalies were largely confined to glycosylated and protease-susceptible loop regions of the domains. Surface accessibility of hydrophobic residues was typical of proteins with extensive domain interactions, a finding compatible with the hydrodynamic properties of alpha -agglutinin and the hydrophobic nature of binding to its peptide ligand alpha-agglutinin. The procedures used to align the alpha-agglutinin sequence and test the quality of the model may be applicable to other proteins, especially those that resist crystallization because of extensive glycosylation.

Algorithms↗
PubMed2004

The ER-Golgi v-SNARE Bet1p is required for cross-linking alpha-agglutinin to the cell wall in yeast.

In Saccharomyces cerevisiae, glycosylphosphatidylinositol (GPI)-anchored cell wall mannoproteins, including alpha-agglutinin, are secreted to the cell surface through vesicular transport pathways. At the cell surface the GPI anchors are cleaved within the glycan, then transglycosylated to form a covalent cross-link to 1,6-beta-glucan. Among mutants that were temperature-sensitive for growth and for ability to cross-link the mannoprotein alpha-agglutinin to the cell wall, one strain was complemented by BET1, which encodes an ER-Golgi v-SNARE. Temperature-sensitive mutations in BET1 caused aberrations in cell wall structure, including excretion of alpha-agglutinin into the medium, sensitivity to lysis with Zymolyase and hypersensitivity to Calcofluor White. At restrictive temperatures, bet1 mutations block secretion of invertase and other proteins, but alpha-agglutinin was excreted into the extracellular medium. In wild-type parental or bet1 cells, secretion of alpha-agglutinin also continued after protein synthesis was blocked with cycloheximide. This secretion was due to continued export of a significant amount of alpha-agglutinin from compartments distal to the BET1-dependent secretion step. Thus, in bet1 cells the ER-Golgi block allowed secretion to continue, but prevented cell wall incorporation of the alpha-agglutinin. Therefore, a mutation early in the secretion pathway caused aberrant cell wall synthesis by preventing localization of key components required in wall cross-links.

Cell Wall↗
PubMed1988

Light Affects Flagellar Agglutinability in Chlamydomonas eugametos by Modification of the Agglutinin Molecules.

The effect of light on the sexual competence of a light-sensitive mating type minus strain (mt(-)) of Chlamydomonas eugametos obtained by crossing a light-sensitive mating type plus strain (mt(+)) with a light-insensitive mt(-) strain is described. As previously demonstrated for the mt(+) parent, this study of one of the mt(-) offspring shows that (a) a light-sensitive mechanism affects flagellar agglutinability in a rapid process that does not require protein synthesis; (b) only the activity of the flagellar agglutinins (glycoproteins responsible for agglutination) is susceptible to light while agglutinins on the cell body surface are not affected by light. We further demonstrate that (a) membrane vesicles naturally released from nonagglutinable dark gametes remain inactive. Extracts of these vesicles also remain inactive even though they contain agglutinin-like components; (b) inactive mt(-) agglutinin is present in extracts of flagella from nonagglutinable dark gametes by comparison of its chromatographic, electrophoretic, and immunogenic properties with those of active agglutinin. When purified of all other flagellar proteins, it remains inactive; (c) a monoclonal antibody directed against the sexual agglutination site of the mt(-) agglutintin discriminates between active and inactive agglutinins when present in a native state on the flagellar surface, but is unable to discriminate between them when they are denatured in sodium dodecyl sulfate-electrophoresis gels and blotted onto nitrocellulose. Taken collectively these observations suggest that light activation involves the chemical modification of the agglutinins in situ on the flagellar surface.

Journal Article↗
PubMed1968

Chronic hemolytic anemia due to cold agglutinins. II. The role of C' in red cell destruction.

The sera of four patients with chronic hemolytic anemia due to cold agglutinins deposited C' globulins on normal red cells at 37 degrees C. The circulating cells of the patients were heavily coated with C' complex and were relatively resistant to C' hemolysis by cold agglutinin. Such red cells were removed from the patients' circulation at an exponential rate with (51)Cr t((1/2)) that varied from 7 to 19 days. Normal red cells were removed rapidly by hepatic sequestration during the first hours in the patients' circulation. Thereafter, a slower rate of abnormal destruction occurred which was associated with the accumulation of C' complexes on the red cell and the development of resistance to C' hemolysis by cold agglutinin. Normal red cells coated with sufficient C' complex by action of cold agglutinins in vitro to produce resistance to C' hemolysis by cold agglutinins demonstrated varying degrees of improved survival during the first hours in the circulation of three of the patients. The levels of serum C' were reduced in all four patients with chronic hemolytic anemia due to cold agglutinins. Transfusion of large volumes of normal red cells into two patients further reduced serum C'. (51)Cr-labeled normal red cells survived longer after red cell transfusions than before, because of less rapid destruction during the first hours in the circulation. The reduction in serum C' levels appeared responsible for the improved survival. In subjects without cold agglutinins, the presence of the spleen decreased the survival of red cells from a patient who had previously undergone splenectomy. Splenic removal also predominated in the reduced survival of autologous red cells in one patient. Neither hepatic nor splenic mechanisms predominated in removing autologous C'-coated cells in the other two patients.

Aged↗
PubMed1997

[Non-Hodgkin's lymphoma associated with cold agglutinin disease].

Autoimmune hemolytic anemia (AIHA) complicated with non-Hodgkin's lymphoma (NHL) is not unusual. Two cases of NHL associated with cold agglutinin disease were reported. Case 1: A 38-year-old man had diffuse medium-sized cell NHL diagnosed by cervical lymph node biopsy. The Hb was 7.6 g/dl with a cold agglutinin titer of 32,768, and the IgM level was 890 mg/dl (I-specific), so cold agglutinin disease (CAD) was suspected. After administration of COP-BLAM therapy, complete remission (CR) was achieved along with a decrease in the cold agglutinin titer and improvement of anemia. Case 2: A 68-year-old woman had follicular mixed NHL diagnosed by inguinal lymph node biopsy. The Hb was 8.2 g/dl with a cold agglutinin titer of 51,200, and an IgM level of 920 mg/dl (I specific), thus concurrent CAD was suspected. Biweekly COP-BLAM therapy was administered and CR was achieved along with a decrease in the cold agglutinin titer and improvement of her anemia. In both patients, the cold agglutinin titer decreased after CR was achieved suggesting that production of anti-erythrocyte autoantibody was due to disturbance of the antibody system by NHL.

Adult↗
PubMed1987

Isolation and composition of the constitutive agglutinins from haploid Saccharomyces cerevisiae cells.

Sex-specific agglutinins from the cell surface of haploid cells of Saccharomyces cerevisiae (X2180, mta and mt alpha) were purified and analysed. The constitutive agglutinin from mta cells was extractable with 3 mM dithiothreitol. It was shown to be a glycoprotein (3% mannose) with an apparent Mr of 43,000 based on gel filtration, but in SDS-PAGE it behaved as a much smaller molecule (Mr between 18,000 and 26,000). About one in three amino acids was a hydroxyamino acid. Its biological activity was resistant to boiling for 1 h, but sensitive to pronase. Intact mt alpha cells retained their agglutinability in the presence of dithiothreitol but limited trypsinizing released a biologically active agglutinin fragment. It had an apparent Mr of 320,000 (gel filtration). When analysed by SDS-PAGE, a single diffuse band with an apparent Mr of 225,000 was observed. The protein was 94% (w/w) mannose with a trace of N-acetyl glucosamine. Its biological activity was almost completely lost after boiling for 1 h. Both agglutinins behaved as monovalent molecules and specifically inhibited the biological activity of both noninduced and pheromone-induced cells. Pheromone treatment of mta cells resulted in an apparent 32-fold increase in agglutinin activity at the cell surface, whereas pheromone treatment of mt alpha cells only doubled the apparent agglutinin activity.

Agglutinins↗
PubMed1979

Human cold agglutinins against "cryptic" erythrocyte antigens.

Two examples of human IgM cold agglutinins agglutinated human RBC only after enzyme treatment in vitro. Proteases were optimally effective, neuraminidase was also effective. The cold agglutinins did not coat native RBC but were directed against "cryptic" RBC determinants. The cold agglutinins belonged to the anti -I/-i complex indicating a "new" type of I/i determinants. They were strongly accessible to cold agglutinin interaction on native RBC of a patient with congenital dyserythropoietic anaemia. Enzyme treatment of RBC was shown to be not only suited for defining cold agglutinin specificities but also essential for detecting the "new" type of cold agglutinins, obviously causing autoimmune haemolytic anaemia in vivo.

Aged↗
PubMed1979

Purification, characterization and identification of an agglutinin in human serum.

A serum protein named agglutinin is able to induce mitochondria to agglutinate. The protein has been purified from human serum by chromatography on DE-52. Sephadex G-200 and immunoglobulin-Sepharose 4B columns. Agglutinin is a glycoprotein that migrates electrophoretically as a gamma-globulin. Its molecular weight was determined to be 50,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Monospecific antiserum prepared against the agglutinin was found to be identical with anti-beta 2-glycoprotein I and agglutinating activity could be adsorbed on anti-beta 2-glycoprotein I-Sepharose 4B columns. Thus, the agglutinin has been identified as beta 2-glycoprotein I. The reaction between mitochondria and agglutinin shows positive cooperativity, which is independent on the stage of purification of agglutinin. The agglutinating activity could be diminished (inhibited) by acidic non-soluble lipids such as oleic acid, phosphatidic acid, phosphatidyl serine and phosphatidyl inositol.

Agglutination Tests↗
PubMed1989

Alpha-agglutinin expression in Saccharomyces cerevisiae.

A polyclonal antiserum raised against purified alpha-agglutinin was made specific for alpha-agglutinin after adsorption with a cells. The adsorbed antiserum identified alpha-agglutinin peptides on Western blots and bound to cell surface alpha-agglutinin, inhibiting the binding of alpha cells to a cells. Using the antibody, we have determined that 1) the surface distribution of alpha-agglutinin on alpha cells is polar, 2) about 5 x 10(4) molecules/cell are constitutively expressed on strain X2180-1B (alpha) cells, and 3) treatment of alpha cells with the sex pheromone a-factor causes an increase in cell surface alpha-agglutinin, consistent with the a-factor induced increase in cell agglutinability.

Agglutinins↗
PubMed1988

Purification and characterization of an agglutinin from mucus of the snail Achatina fulica.

The mucus of the snail Achatina fulica shows the presence of an agglutinin that nonspecifically agglutinates human erythrocytes. The agglutinin has been purified by affinity chromatography using Sepharose 4B-hog gastric mucin as the affinity matrix. Homogeneity was checked by polyacrylamide gel electrophoresis, immunodiffusion, immunoelectrophoresis, and gel filtration. The agglutinin is a glycoprotein of native molecular weight 70,000. The isoelectric point of the protein was found to be 8.0. The predominant amino acids are aspartic acid and glutamic acid (or amides) and serine, which account for 32% of the total amino acid residues. The agglutinin has 10% carbohydrate (wt/wt) and the most abundant sugar is N-acetylglucosamine. The cd spectra of the agglutinin show the presence of random coil conformation. The inhibition of hemagglutination data indicates that the agglutinin is specific for beta glycosides of D-Gal and D-GalNAc.

Agglutinins↗
PubMed1991

Spinal neurons in the zebrafish labeled with fluoro-gold and wheat-germ agglutinin.

This study concerns the identification and location of interneurons in the spinal cord of the zebrafish by way of retrograde tracing from the body musculature. To distinguish motoneurons from interneurons; two tracers were applied: the fluorochrome Fluoro-Gold to label motoneurons, and the trans-synaptically transported compound wheat-germ agglutinin to label motoneurons and the associated interneurons that are considered to be premotoneurons. Because the tracer accumulated mainly in cell bodies (not in neurites), premotoneurons labeled directly from motoneurons could not be distinguished from those labeled via interjacent cells. Both tracers were unilaterally injected into the myotomal muscle at the anal level of the animal. The number of labeled cell bodies in the spinal cord was examined 6, 10 and 16 days after injection. Several technique-oriented experiments were performed in order to map all pathways along with the tracers were incorporated in the neurons. The following observations were made. (1) All Fluoro-Gold-positive cells contained wheat-germ agglutinin, but yet more cells contained only wheat-germ agglutinin; the number of wheat-germ agglutinin-labeled cells was about tenfold higher than the number of Fluoro-Gold-labeled cells. (2) Fluoro-Gold labeling was restricted to cells within one to two spinal cord segments corresponding to the injection site, whereas wheat-germ agglutinin labeling was more diffuse. (3) The position and size of Fluoro-Gold-labeled cells corresponded to those of motoneurons described in previous horse-radish peroxidase experiments. (4) Statistical analysis of the group of wheat-germ agglutinin-labeled cells showed two subpopulations, one with a mean cell size and position corresponding to motoneurons and one with a smaller mean cell size, also positioned within the motor column. The smaller cells were considered to be premotoneurons. The ratio motoneuron:premotoneuron was lowest in the ventrolateral area of the motor column.

Animals↗
PubMed2004

[Cold agglutinins, clinical presentation and significance; retrospective analysis of 58 patients].

PURPOSE: To describe clinical, biological characteristics and associated diseases of cold agglutinins in adults. METHODS: Retrospective study in a single department of internal medicine from 1997 to 2002. The inclusion criteria were a positive direct Coombs test and a positive research for cold-reactive autoantibodies. We recorded for each patient: clinical presentation at onset and during follow-up, biological parameters of haemolysis, biological characteristics of the cold agglutinin and associated diseases. RESULTS: Fifty-eight patients (34 females, 24 males), with medium age of 58.8 were included in the study. Clinical presentation was highly variable between acute life-threatening haemolysis and absence of symptoms. Results of direct antiglobulin test were C3 (74%), IgG + C3 (22.4%), IgG (3.4%). Titer, thermal amplitude, strength and specificity of Coombs test were correlated, in all cases except 6, with cold agglutinin haemolytic activity. In 77.6% of cases cold agglutinin was secondary; related to: autoimmune disorders (n = 19), lymphoproliferative disorders (n = 11) and infections (n = 10). CONCLUSION: Clinical presentation of cold agglutinin is highly variable and not always related to the biological characteristics of the bound antibody (titer, thermal amplitude, specificity). In our single center study, diseases associated with cold agglutinin were various with the highest frequency of auto-immune disorders. Our study underlined also the high frequency of lymphoproliferative disorders and justifies a close follow-up of these patients. Finally, we reported a high frequency of hepatitis C virus infection among the infectious aetiologies.

Adult↗
PubMed1958

Studies on the transfer of lymph node cells. XI. Effect on the anti-Shigella agglutinin titers of recipient rabbits of the prior injection of leucocytes from the donor animals.

The transfer to rabbits of homologous lymph node cells which have been incubated in vitro with Shigella-trypsin filtrate leads to the appearance of agglutinins to Shigella in the sera of the recipients. In the present study it has been found that the prior injection of the prospective recipients with blood leucocytes from the donor animals prevented the appearance of anti-Shigella agglutinins. The following observations have been made in this system: 1. The degree of the pre-injection effect was found to be a function of the number of leucocytes injected and of the interval between such pre-injection and the transfer of the antigen-incubated lymph node cells. 2. The pre-injection of leucocytes at appropriate intervals could also cause the failure of antibody to appear in sera of recipients of lymph node cells when these were obtained from donor rabbits injected with Shigella, 1, 2, or 3 days prior to cell transfer. 3. Agglutinins failed to appear in cell-transfer experiments after the pre-injection not only of blood leucocytes, but also of lymph node cells, peritoneal exudate cells, or thymus cells of rabbits. This effect was not brought about by pre-injection of erythrocytes of rabbits or leucocytes of chicken, cow, or horse. The pre-injection of leucocytes of human blood had an effect of partial suppression. 4. When the leucocytes for pre-injection were pooled from groups of rabbits, either the prospective donors of the lymph node cells or other rabbits, essentially complete suppression of agglutinin titers occurred regularly. When the leucocytes for pre-injection were obtained from an individual rabbit and the lymph node cells from another rabbit the suppression of the recipients' titers occurred sporadically. 5. When the recipient's own leucocytes were pre-injected the subsequent agglutinin titers were somewhat lower than those of the non-pre-injected controls. When the recipient's whole blood was re-injected as the source of leucocytes the subsequent agglutinin titers were as high as those of the non-pre-injected controls. 6. The pre-injection effect was not obtained if the leucocytes had been heated, frozen and thawed, suspended in distilled water, lyophilized, or treated with sodium iodoacetate. However, sonic oscillation or x-irradiation of the leucocytes had no effect on their capacity to bring about the pre-injection effect.

Agglutination↗
PubMed1997

Immunomodulatory effects of Viscum album agglutinin-I on natural immunity.

In 24 h cultured human peripheral blood mononuclear cells, treated with various (1 microgram/ml to 1 ng/ml) concentrations of Viscum album agglutinin-I, quantitative assessment of DNA breaks labelled with terminal deoxynucleotidyl transferase revealed a dose-dependent Viscum album agglutinin-I-induced apoptosis above a lectin concentration of 10 ng/ml. After 24 h incubation of peripheral blood mononuclear cells with non-cytotoxic concentrations of Viscum album agglutinin-I (10 and 1 ng/ml), messenger (m)RNA expression and secretion of a panel of cytokines were evaluated by reverse polymerase chain reaction and by enzyme-linked immunosorbent assay (ELISA), respectively. The lectin induced expression of interleukin-1 alpha, interleukin-1 beta, interleukin-6, tumor necrosis factor-alpha, interferon-gamma, granulocyte-monocyte colony stimulating factor and interleukin-10 genes, but no expression of interleukin-2 or interferon-gamma production could be detected. In addition, cellular components of the natural immune system (such as monocytes and granulocytes) bound Viscum album agglutinin-I molecules to a higher degree than lymphocytes. To establish the modulatory potency of Viscum album agglutinin-I on the natural immunity of human subjects, four randomized, double-blind crossover trials were performed on healthy volunteers. In contrast to the significant lectin-induced increases in number and activity of natural killer cells observed in animal models, in the first and second trial human healthy individuals showed no significant differences between their natural killer responses following an injection of lectin-enriched preparation or saline. Due to considerable intrinsic fluctuation of these parameters, a third and fourth double-blind trial with freshly isolated Viscum album agglutinin-I was performed using a more rapidly detectable parameter, the priming of granulocytes. Here, significant lectin-induced increases were found.

Agglutinins↗
PubMed1986

Hemolytic anemia due to a mixture of low-titer IgG lambda and IgM lambda agglutinins reacting optimally at 22 degrees C.

A 65-year-old white man had severe hemolytic anemia due to a mixture of low-titer IgG lambda and IgM lambda agglutinins showing optimum reactivity at 22 degrees C. The IgG agglutinins were detected by manual indirect antiglobulin test (IAT) using anti-IgG, and had a titer of 1 at 37 degrees C, 128 at 22 degrees C and 16 at 4 degrees C against adult type O red blood cells (RBC). The corresponding titers with cord RBC were 1 (37 degrees C), 64 (22 degrees C) and 8 (4 degrees C). Proteolytic enzyme and neuraminidase treatment of RBC did not decrease these titers. No known specificity could be assigned to these agglutinins. The isolated agglutinins (recovered by cold adsorption, warm elution) were shown by immunoelectrophoresis to be IgG lambda antibodies. They did not bind complement in vitro, consistent with the finding that the patient had negative manual direct antiglobulin test (DAT) by anti-C3d. It could be shown only by automated IAT that patient's serum also contained IgM cold agglutinins which also reacted best at 22 degrees C and appeared to be of lambda light-chain type. The patient responded to corticosteroid therapy and remains well without treatment 14 months after the hemolytic episode. The presence of IgG cold agglutinins may be predictive of a favorable response to corticosteroid therapy.

Aged↗
PubMed1983

Characterization of a salivary agglutinin reacting with a serotype c strain of Streptococcus mutans.

A protein, which can agglutinate a Streptococcus mutans serotype c strain, was isolated from parotid saliva by affinity adsorption of the salivary agglutinin to the microorganism followed by a desorption with a 10 mM phosphate buffer. The agglutinin was subjected to preparative ultracentrifugation, gel filtration, and ultrafiltration. The native purified agglutinin is active only in the presence of Ca. Polyacrylamide gel electrophoresis, analytical centrifugation, and analyses of amino acids and carbohydrates showed that the native agglutinin was a fucose-rich glycoprotein with a carbohydrate content of 45% and with a molecular weight of at least 5 X 10(6). After sodium dodecyl sulphate treatment the molecular weight was 4.4 X 10(5). There was a low content of proline and a high content of aspartic acid, serine and threonine. The concentration of agglutinin in parotid saliva is less than 0.5% of total protein. It has high biological activity: 0.1 microgram agglutinin causes a rapid aggregation of approximately 10(8) bacteria.

Agglutination Tests↗
PubMed1990

Lactose- and heparin-inhibitable agglutinin from human fetal brain.

An agglutinin activity which was sensitive to lactose and heparin was estimated during prenatal brain development. The agglutinin showed higher specific activities in cerebral cortex and midbrain. There was an increase in lectin specific activity in all the brain regions with development. In addition to brain, other fetal organs also showed the presence of developmentally regulated agglutinin. Cerebral cortical agglutinin was purified by Sepharose CL-6B gel filtration and asialofetuin- and heparin-Sepharose affinity chromatography. Purified agglutinin was strongly inhibited by lactose, asialofetuin, and heparin. It showed no requirement for divalent cations and was maximally active at pH 8.0. Electrophoretic characterization showed the aggregate nature of the agglutinin, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis gave subunit molecular weights of 58,000, 45,000, and 24,000.

Agglutinins↗