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A newly isolated lectin from the plant pathogenic fungus Sclerotium rolfsii: purification, characterization and role in mycoparasitism.

A novel lectin was isolated and purified from the culture filtrate of the soilborne plant pathogenic fungus Sclerotium rolfsii by anion-exchange chromatography using a DEAE-Sepharose column. The lectin came through the column with the flow-through, whereas all the non-agglutinating proteins present in the crude preparation remained bound to the column until elution in a NaCl gradient. SDS-PAGE analysis of the agglutinating fraction revealed a single band corresponding to a protein with a molecular mass of approximately 45 kDa. Agglutination of Escherichia coli cells by the purified lectin was not inhibited by any of the mono- or disaccharides tested, whereas the glycoproteins mucin and asialomucin did inhibit agglutination. Proteases, as well as 1,3-beta-glucanase, were found to be totally destructive to agglutination activity, indicating that both protein and 1,3-beta-glucan are necessary for agglutination. Using a biomimetic system based on binding of the lectin to the surface of inert nylon fibres revealed that the presence of the purified agglutinin on the surface of the fibres specifically induced mycoparasitic behaviour in Trichoderma harzianum. Trichoderma formed tightly adhering coils, which were significantly more frequent with the purified agglutinin-treated fibres than with untreated ones or with those treated with non-agglutinating extracellular proteins from S. rolfsil. Other mycoparasite-related structures, such as appressorium-like bodies and hyphal loops, were only observed in the interaction between T. harzianum and the purified agglutinin-treated fibres.

Escherichia coli↗

Characterization of antibodies directed against platelet cryptantigens detected during the immunological study of 356 consecutive patients with presumed autoimmune thrombocytopenia (AITP).

Cryptic antigens are detected by antibodies present in a wide spectrum of patients with or without thrombocytopenia, and even in healthy individuals. They are produced for unknown reasons and do not react with antigens of native platelets, but only with altered platelets. Cryptantigen antibodies may not only result in spuriously low platelet counts, but also in 'falsely' positive tests for platelet antibodies. We report our experience in the characterization of the different types of antibodies directed against cryptantigens of platelets: EDTA-dependent antibodies, PFA-dependent antibodies, EDTA-PFA-dependent antibodies and cold agglutinins. These antibodies were detected in the course of the serological study of 37 patients from a group of 356 (10%) whose blood was sent to our laboratory for platelet antibody testing. Pseudothrombocytopenia was diagnosed in 24 cases. Twenty-one of these showed EDTA-dependent or EDTA-PFA-dependent platelet agglutination and three were due to the presence of cold agglutinins. In 13 patients the thrombocytopenia was genuine. Eleven of these presented EDTA-dependent or EDTA-PFA-dependent antibodies in their serum and in the two remaining cases PFA-dependent antibodies were found. Cryptantigen antibodies were also detected in 9 out of 228 (4%) blood donors who were used as healthy controls in the platelet immunofluorescence test. In the light of the results obtained we put forward some guidelines to detect the presence of these antibodies and establish an accurate serological and clinical diagnosis of the autoimmune thrombocytopenias.

Adolescent↗

Differentiation of Leishmania strains of Indian origin by lectin-mediated agglutination.

Characterisation of surface saccharides was carried out in 3 different strains of Indian leishmaniae by 7 lectins. Energy dependent agglutination and role of cytoskeletal disintegrator were also analysed. Wisteria floribunda, peanut agglutinin and soybean agglutinin can be used to differentiate clearly the leishmanial strains causing disease like visceral leishmaniasis, post Kala-azar dermal leishmaniasis and cutaneous leishmaniasis. The remaining lectins have mixed agglutination behaviour towards these strains. The effective concentration of dinitrophenol, sodium azide and colchicine is 10 mM, 25 mM and 1.25 x 10(-2) M, respectively.

Agglutination Tests↗

Characterization of thymocyte subpopulations by enzymatic markers.

The activities of ecto-5'-nucleotidase (E5N), deoxyadenosine kinase (dAK) and deoxyguanosine kinase (dGK), were determined in thymocyte subpopulations, separated by peanut agglutinin (PNA). The activity of dAK in the PNA+ (agglutinated by PNA) thymocyte subpopulation was 2.5-fold that in the PNA- subpopulation. The activities of E5N and of dKG were found to be higher in the PNA- than in the PNA+ subpopulation by 15- and 4-fold, respectively. The activity of these enzymes can therefore be utilized to characterize the thymocyte subpopulation. In addition, since PNA+ cells are considered to be young immature precursors of the PNA- thymocytes, the activity of these enzymes may serve also as markers for the degree of maturation of the T cells.

5'-Nucleotidase↗

[Preparation of partially fixed erythrocytes and its application for immunohematologic examination].

A suspension of washed human erythrocytes (2%) in PBS was mixed with an equal volume of 1 mM glutaraldehyde (GA) and allowed to stand at laboratory temperatures, followed by washing with normal saline. The agglutinability of the erythrocytes toward anti-A, anti-B, anti-M and anti-N reagents remained unchanged after GA treatment shorter than 20 minutes, and the agglutinability toward anti-C, anti-c, anti-D, anti-E, anti-e, anti-Lea, anti-Leb and anti-P1 did not decrease after treatment for 10 minutes. GA treatment for longer periods of time than the above caused a decrease of the reactivities. The agglutinability toward an anti-H (Ulex europaeus) and other lectins increased after 10 to 30 minutes of GA treatment and decreased after 40 minutes or more of exposure to GA. These results indicate that the immunologic agglutinability of erythrocytes were practically unchanged after a 10 minutes treatment with 1 mM GA (a mild fixation procedure hereafter called "partial fixation"). The properties of the partially fixed erythrocytes were closely similar to those of untreated erythrocytes as regards cell volume, membrane fragility in hypotonic solutions (measured by a modification of the Ribiere method), and membrane fragility under continuous shaking. The resistance of the partially fixed erythrocytes heating up to 50 degrees C was superior to that of the untreated erythrocytes. From these results, the deformability of the partially fixed erythrocytes was concluded to be similar to that of untreated erythrocytes. After storage for 6 months at 4 degrees C in Alsever solution containing adenine and inosine, the shapes of the untreated erythrocytes changed to "spherocytes" or "echinocytes", whereas the partially fixed cells retained the original discocyte shape. Blood grouping laboratory tests were performed with the partially fixed erythrocytes as indicators. Both anti-A and anti-B agglutinins in normal human sera could be detected without difficulty. Presence of irregular agglutinins, such as anti-H and anti-N, in healthy donors' sera could also be detected, as with the freshly obtained erythrocytes. The detection limits of an incomplete anti-D agglutinin were equal to those in the tests with untreated erythrocytes. The partially fixed erythrocyte (stored at 4 degrees C for 2.5 to 3 months) were used as indicators of ABO-blood grouping from blood stains, saliva stains and hairs by the agglutinin-inhibition test, absorption-elution test or mixed agglutination test. The results obtained were practically equal to those of the tests with freshly obtained erythrocytes, indicating the availabilities of the partially fixed erythrocytes.

Blood Grouping and Crossmatching↗

Quantitative assay for lectin-induced cytoagglutination by means of an electronic particle-counting technique.

A method employing an electronic particle-counting technique was used to quantify lectin-induced agglutination of human granulocytes and lymphocytes with either concanavalin A or wheat germ agglutinin. The number and mean volume of single cells and aggregates in the presence of increasing concentrations of lectin were computed from 95% confidence intervals. Agglutination depended on both the number of free cells and the number and size of the cell clusters. Changes in these two variables were mutually independent of one another, and both were simultaneously determined. An index of agglutination that takes the effect of these two variables into account was defined as (formula: see text) VA equals mean volume of cell aggregates, NS equals number of single cells, NA equals number of cell aggregates, VS equals mean volume of single cells, rb equals r at a given lectin concentration, and ra equals r in the absence of lectin. For any combination of lectin and cell type, the agglutination curve, as described by zeta, consisted of two components: a) a flat region in which zeta remained constant with increasing lectin concentrations and b) a region in which zeta increased linearly as a function of the logarithm of lectin concentration. The shapes of these curves offered two parameters for quantitative comparison of agglutinability: 1)threshold concentration, defined as the minimum concentration of lectin (microgram/ml) required to bring about a measurable rise in zeta and 2) the concentration gradient, defined as the change in zeta for an increase of one log unit in the concentration of the lectin in the range beyond the threshold concentration. This method offers a high degree of quantification and provides reliable information that can be meaningfully correlated with cell surface characteristics.

Agglutination↗

Immunoclinical correlation in diabetes mellitus. A preliminary report on the lectin-agglutination test.

Twenty cases with insulin dependent diabetes mellitus (IDDM) were studied and compared with a control group with non insulin dependent diabetes mellitus (NIDDM) and another group of nondiabetic healthy persons. Lymphocytes of each group were tested for agglutination with three sets of lectins: concavalin A (ConA), soyabean agglutinin (SBA) and peanut agglutinin (PNA). SBA test, being highly positive in IDDM and persistently negative in NIDDM, is the most significant of the three tests for differentiating between the two types of diabetes mellitus.

Adolescent↗

Immunological relations of proteins from four salmonellae sharing an "O" factor 8.

The proteins from S. virginia, with the sole 8 "O" factor, precipitated against homologous and related heterologous sera by a conspicuous, homogenous line of serological identity, with proteins from: S. newport (6.8), S. blockley (6.8), S. emek (8.20). The proteins, however, were not involved in the bacterial agglutinations since the absorptions, which removed the common precipitins from the sera, did not modify the homologous agglutinations. The results with anti-S. newport and anti-S. blockley sera sharing identical "O" factors while displaying different immunochemical compositions as well as the strong immunochemical relations found between S. virginia and S. newport belonging to the different subgroups C2 and C3 underline the non-relatedness of agglutinins and precipitins.

Agglutination Tests↗

Suppression of chemotactic activity of human polymorphonuclears by monoclonal IgMs with and without biological activity.

The influence of monoclonal IgMs on migration of human polymorphonuclears was studied at various temperatures by the use of 19 sera with monoclonal IgMs from patients with macroglobulinemia of Waldenstrom (MW) without obvious biological activity, 29 sera with monoclonal IgM cold agglutinins (18 with anti-I and 11 with anti-i IgMs) and 3 sera with monoclonal IgM rheumatoid factor (RF). Under-agarose migration method and modified Boyden chamber method with double filters and 51Cr-PMNs were used. In under-agarose method, chemotactic differentials for controls, MW, anti-I, and anti-i groups were, respectively, 57 +/- 8 mm, 39 +/- 9 mm, 44 +/- 14 mm, and 32 +/- 16 mm at 37 degrees C and 47 +/- 18 mm, 22 +/- 11 mm, 17 +/- 9 mm, and 15 +/- 12 mm at 24 degrees C. All three sera with IgM RF inhibited chemotaxis. The differences between all groups and controls were significant at p less than 0.01. Random migration was inhibited at 24 degrees C (p less than 0.01) but not at 37 degrees C. Inhibitory concentrations of IgM in the sera tested were equal or less than 0.5 mg/ml. Thirteen sera were tested by the modified Boyden chamber method. At 37 degrees C 8 of 13 sera and at 24 degrees C 11 of 13 sera inhibited significantly chemotaxis at a concentration of IgM of 1 mg/ml. The lowest inhibitory concentration of IgM was 25 micrograms/ml. Eleven chromatographically pure IgMs were tested in the under-agarose assay. At concentrations of 0.4-3.7 mg/ml, eight IgMs inhibited chemotactic differential at 37 degrees C and nine inhibited it at 24 degrees C. At concentrations of 0.6-2.0 mg/ml, all seven pure IgMs tested by the Boyden chamber method significantly inhibited chemotaxis at 24 degrees C and 37 degrees C. Some IgMs inhibited chemotaxis at concentrations as low as 25 micrograms/ml. Ten IgM CA were eluted from the red blood cells. Eluates inhibited strongly chemotaxis at 24 degrees C and 37 degrees C. Heat inactivation did not alter inhibitory activity of IgM, however pepsin digestion or reduction and alkylation of purified IgMs did abolish their inhibitory activity. Inhibition of chemotaxis was not related to the light chain type, the titre, or the thermoamplitude of cold agglutination. However, monoclonal IgMs with anti-i cold agglutinin activity were stronger inhibitors than anti-I. Since 75% of IgMs tested inhibited chemotaxis at 37 degrees C, it is possible that monoclonal IgMs, especially those with anti-i cold agglutinin activity, inhibit PMN migration in vivo.

Agglutinins↗

The effect of haemagglutinating factor from boar seminal vesicle fluid on leucocytes.

Complete agglutination of porcine, bovine, ovine, and rabbit leucocytes and of porcine and bovine thrombocytes was observed after their exposure to a 1% solution of the haemagglutinating protein isolated from boar seminal fluid. Bull seminal vesicle fluid had the same agglutinating effect on leucocytes, but did not agglutinate thrombocytes. Ram seminal plasma and other fluids from the reproductive tract of boar and bull did not agglutinate either leucocytes or thrombocytes. A viability test showed that the agglutinin of boar seminal vesicle fluid, bull seminal vesicle fluid, and boar prostate fluid were all lethal for leucocytes.

Agglutination↗

Studies on the relationship between Yersinia enterocolitica IX and Brucella abortus agglutinins in naturally infected animals.

Attempts were made to define the Brucella abortus and Yersinia enterocolitica IX infection status of animal populations by means of selected agglutination tests. The Brucella abortus O, the Yersinia enterocolitica IX OH and the Y enterocolitica IX H agglutinin titres were measured in a large number of cattle, goat and pig sera In the goats and, to a much lesser extent, the pigs, the relationships between these titres suggested that Yersinia infection was common. In contrast, the results from the cattle sera were complex and tended to indicate the presence of both Yersinia infection and brucellosis.

Agglutinins↗

Characteristics of two wheat germ agglutinin-resistant variants of B16 mouse melanoma cells with reduced tumorigenicity.

Two variants of B16 mouse melanoma cells, selected for their resistance to toxic levels of wheat germ agglutinin isolectin 1 (WGA-1) in serum-free medium, showed by chromosome analysis that they are still mouse cell-lines, continue to produce melanin, and are less tumorigenic in mice than the parent B16 cells. The variants showed a marked decrease in cell agglutination with the wheat germ lectin and a slight increase in cell agglutination with concanavalin A. The binding of 125I-labeled wheat germ agglutinin to the two variant lines was likewise decreased over a 10(3)-fold range of lectin concentrations. Terminal sialyl residues were critical in WGA-1 binding to the wild-type cells. The binding data indicated a decrease in high-affinity binding as well as a decrease in the total number of binding sites in the variants. Polyacrylamide gel electrophoresis, followed by affinity staining with 125I-wheat germ agglutinin, showed alterations in the wheat germ agglutinin-binding glycoproteins in the variants compared to those of the parent cell line. However, lactoperoxidase-catalyzed iodination revealed a similar cell-surface protein pattern among the three cell lines. Radioactive glycoproteins secreted or shed by the three cell lines grown in the presence of [3H]glucosamine in serum-free medium were fractionated on the basis of their interaction with WGA-Sepharose (2 mg/mL). The WGA-bound glycoproteins from the two variants had molecular weights of 92,000, 56,000, and 42,000. None of these components was detected in the parent cell-line. A major WGA-binding glycoprotein, which accounted for 37% of the total [3H]glucosamine incorporated, was isolated from the spent medium of the parent mouse melanoma cell-line. This glycoprotein was apparently absent in the WGA-1-resistant variants.

Agglutination Tests↗

Escherichia coli antibodies in patients with inflammatory bowel disease.

Sera from 30 patients with inflammatory bowel disease (IBD) (16 with Crohn's disease (CD) and 14 with ulcerative colitis (UC) were assayed for the presence of antibodies against 159 Escherichia coli O-antigens and compared with sera from 16 matched control subjects. The majority of patients with IBD had agglutinating antibodies to a higher number of Escherichia coli O-antigens and in higher titres than the control group. The number of positive agglutinins was O-33 mean 13.8 in CD, O-26 mean 7.9 for UC, and O-7 mean 1.5 in controls. Eight patients with IBD and arthropathy had antibodies to fewer O-antigens (O-7 mean 3.2). The antibodies were in the IgG and IgM, in titres corresponding to original values. No specific O-serotypes were associated with IBD. Common serotypes, R-plasmid carrying serotypes, and those associated with shigella-like adult diarrhoea were detected. O14 was detected only in five patients and O119 in none. There was no correlation between the number of Escherichia coli agglutinins and the site and severity of the disease or type of therapy. It is suggested that the presence of the high numbers of Escherichia coli antibodies is secondary to the disease process and is unlikely to be causally involved in the pathogenesis of the disease, but may play a role in the perpetuation of the disease and in the extraintestinal complications.

Adult↗

Biphasic rate of synthesis of glycoconjugates, phospholipids and DNA in concanavalin A-stimulated mouse thymocytes. Involvement of cortisone-sensitive and -resistant subpopulations.

The time course of the rate of labeling of membrane components (phospholipids, glycolipids and glycoproteins) and DNA was followed in concanavalin A-stimulated CBA/J mouse thymocyte cultures. Two peaks of stimulated biosynthetic activity were noted, the first at the beginning of the cultivation and the second about 25 h later. Both early and late peaks of biosynthesis of membrane components were accompanied by blast transformation and were unimpeded by suppression of DNA synthesis by hydroxyurea. Cortisone-sensitive and cortisone-resistant thymocytes were prepared by selective agglutination of the cortisone-sensitive cells with peanut agglutinin (Reisner et al. Cell. Immunol. 1976. 25: 129) or cortisone treatment of the animals. Cortisone-sensitive cells responded early, while the cortisone-resistant population gave only the late response. The autoradiographic patterns from sodium dodecyl sulfate polyacrylamide gels of [3H]fucose or [3H]galactose-labeled glycoproteins from early and late labeling cells, and cortisone-resistant cells, were compared. Late-labeling and cortisone-resistant cells gave indistinguishable patterns, but differed significantly in their patterns from early-labeling cells. It is concluded that the two peaks of biosynthetic activity during the course of concanavalin A stimulation of thymocytes are caused by two different cell populations which require different times for maximal response and react independently of one another.

Animals↗

Low sialic acid-bearing mouse thymocytes do not express helper T cell properties in vitro.

Immature, presumably cortical, mouse thymocytes were isolated by removing mature thymocytes by agglutination with the sialic acid-specific lectin, lobster agglutinin 1 (LAg1). These immature cells do not respond to the mitogenic effects of concanavalin A (Con A), even in the presence of interleukin 2. Moreover, they do not exhibit two properties of helper T cells; they do not secrete interleukin 2 when stimulated with Con A, nor do they provide T help for an in vitro immune response by spleen B cells to the T-dependent antigen, sheep erythrocytes. LAg1-negative thymocytes fail to provide T help even though Con A is added to the cultures, regardless of the number of LAg1-negative thymocytes added per culture, and even in the presence of exogenous macrophages. Unseparated thymocytes, LAg1-positive thymocytes and cortisone-resistant thymocytes all provide T cell help under these conditions. These experiments indicate that immature, presumably cortical mouse thymocytes, isolated by virtue of their low levels of surface sialic acid, are inherently unable to provide T cell help in vitro.

Animals↗