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PubMedDate not supplied

Erysipelothrix rhusiopathiae neuraminidase and its role in pathogenicity.

The role of the enzyme neuraminidase in pathogenicity of the bacillus Erysipelothrix rhusiopathiae was studied. Different substances with low and high molecular weight were tested as inducers of E. rhusiopathiae neuraminidase biosynthesis. It was found that macromolecular complexes induce the secretion of the enzyme. K(M) values for different substrates showed that the affinity of the E. rhusiopathiae neuraminidase increases in parallel with the enlargement of the molecular weight of glycoproteins. Results from the rabbits skin test confirmed the role of E. rhusiopathiae neuraminidase as a factor of pathogenicity with spreading functions.

Enzyme Induction↗
PubMed1984

Neuraminidase activity in human peripheral lymphocytes: its increase in chronic active liver disease.

The activity of neuraminidase (sialidase) in peripheral white blood cells was measured by a fluorometric method using 4-MU NANA as a substrate. The activity in mononuclear cells, which was predominantly lymphocytes, was 2.5 times higher than that in polymorphonuclear cells (neutrophils). The former's activity was directly proportional to the number of the cells, but that of the latter was found to be suppressed by an increasing number of cells. Thus, the increased number of PMN contaminated in MNC fraction somewhat obscured neuraminidase activity affecting suppressively . The enzyme activity in MNC of 25 control subjects (15 males and 10 females) was 254 +/- 73 pmoles per hour per 10(6) cells and there was no difference between the values in males and females (233 +/- 59 vs. 284 +/- 81). The activity in 20 patients with chronic active liver disease was significantly higher than that in controls (551 +/- 135, p less than 0.01). The amount of sialic acid in MNC, which was 1.4 times more than that in PMN, revealed a tendency for a positive correlation between neuraminidase activity. A new finding of the increase of lymphocyte neuraminidase activity was introduced and its pathological significance particularly in liver disease was discussed.

Chronic Disease↗
PubMed1975

Peanut agglutinin, a new mitogen that binds to galactosyl sites exposed after neuraminidase treatment.

Peanut agglutinin, purified by affinity chromatography, agglutinates lymphocytes from mouse, rat, guinea pig, and man only after their treatment with neuraminidase. However, it stimulates only neuraminidase-treated rat and human cells. A similar number cell surface receptors for peanut agglutinin was found on neuraminidase-treated rat and mouse lymphocytes although the latter cells were not stimulated by the lectin. Galactose specifically inhibited the agglutination and stimulation of lymphocytes by peanut agglutinin. Sequential treatment of lymphocytes with neuraminidase and beta-galactosidase markedly reduced the response of the cells to stimulation by peanut agglutinin, soybean agglutinin, and galactose oxidase. It is suggested that the same galactosyl residue may be the target for the initial step in triggering lymphocytes by the above mentioned mitogens.

Agglutination Tests↗
PubMed1975

[Role of neuraminidase from cholera vibrions in the pathogenesis of experimental cholera].

A study was made of a possible effect of neuraminidase of cholera vibrios on cholera pathogenesis. It was shown that in intraintestinal injection of cholera vibrios of the El Tor biotype to nursling rabbits neuraminidase could be revealed in their intestine 5 to 8 hours after the infection. Addition of neuraminidase to the weakly cholerogenic strain cholera vibrios intensified its cholerogenic action in infection of the animals. The antineuraminidase serum administered to the infected rabbits prevented clinical manifestations of experimental cholera, although it failed to always eliminate the cholerogenic syndrome (revealed during autopsy). At the same time neuraminidase did not influence the capacity of cholerogen to produce the cholerogenic syndrome. The authors consider that the action of the enzyme should occur at the early stages of the pathogenic process, and could be associated with creation of conditions for the attachement of cholera causative agent to the intestinal wall or for the action of their exotoxin.

Animals↗
PubMed1976

[Immunity against Erysipelothrix rhusiopathiae infection by means of active immunization using homologous neuraminidase (author's transl)].

Neuraminidase may play a role as a pathogenic factor in Erysipelothrix rhusiopathiae infection. The protective effect of active immunization with purified neuraminidase was therefore tested in an infection experiment in white mice. Mice were immunized 2, 4, 6, 8 or 10 times i.p. with Erysipelothrix neuraminidase. A control group received 10 injections with physiological saline. The infective dose varied between 7 and 7 x 10(7) cells. While all control animals infected with 7 x 10(1) germs died, the lethal effect could be reduced to 50% and 25% in animals immunized twice and 4 times, respectively. Only animals immunized 8 and 10 times were still partly protected against germ numbers of 10(3)-10(4). Germ numbers of 10(5) and more were almost always fatal even in highly immunized animals. Even a high immunization with neuraminidase could only lower the lethal by a maximum factor of 10(4) germs used.

Animals↗
PubMedDate not supplied

[Effect of normal and specific immune sera on neuraminidase activity].

We have got evidence that there is no antigenic relationship reflecting the structural similarity between neuraminidases synthesized by noncholera vibrios and Arthrobacter nicotianae. The cross-reactions between the enzymes and heterological antisera were not observed. Antibodies against the A. nicotianae neuraminidase inhibited the activity of the enzyme for a glycomacropeptide of milk whey and for components of the blood serum, and had no effect no the neuraminidase from noncholera vibrios. Antibodies against the neuraminidase of noncholera vibrios inhibited only the activity of the homologous enzyme. Upon gel-filtration on Sephadex G-200 the antibodies inhibiting the activity of the enzymes under study were found in the fraction of 7S-gamma-globulins.

Animals↗
PubMed2006

Neuraminidase antibody response to inactivated influenza virus vaccine following intranasal and intramuscular vaccination.

BACKGROUND: The evaluation of influenza vaccine activity and potency are based on the immune response to hemagglutinin, and protection is indicated when the titer of hemagglutination inhibition serum antibody is > or = 1:40. Neuraminidase, the second surface glycoprotein, may also have a role in protection, but little information is available on the immunologic response to this component. OBJECTIVES: To determine whether any response to neuraminidase is evoked by intranasal immunization with a novel, whole, inactivated anti-influenza vaccine. METHODS: This study was part of a more comprehensive study of mucosal and serum immune response to this vaccine. Fifty-four young adults were immunized intranasally, 9 intramuscularly and 18 received a placebo. Twenty-three elderly people were immunized intramuscularly, and 21 elderly and 17 children were immunized intranasally. Serum and nasal antibodies to antigens N1 and N2 were determined by the lectin neuraminidase test. RESULTS: Serum response following intranasal vaccination was lower than after intramuscular vaccination, and ranged from 21.4 to 35.3% and 33.3 to 64.7% following intranasal vaccination and from 52.2 to 77.8% and 47.8 to 88.9% after intramuscular vaccination, to N1 and N2 respectively. Nasal antibody response was low and was found only after intranasal vaccination, and response to N2 was better than to the N1 antigen. CONCLUSIONS: It may be beneficial if future vaccines would include competent hemagglutinin and neuraminidase, which would afford a higher level of protection.

Administration, Intranasal↗
PubMedDate not supplied

[Catalytic properties of neuraminidase of non-cholera vibrios].

Main catalytic properties of commercially available neuraminidase preparations from noncholeric vibrios were studied. The enzymatic activity was measured using a simple resorcinol procedure. Optimal conditions for neuraminidase effect: pH 5.5-6.0 and buffer composition, were characterized. Affinity of the enzyme to various substrates was studied using 10 natural and synthetic sialoconjugates. Km values were studied for fetuin, ovomucin and transferrin used as optimal substrates. When influence of meta ions, detergents, complexes and other compounds was studied, activation of neuraminidase was found in presence of bivalent metal ions, especially of Ca2+, while chelate-forming complexes and heavy metal salts inhibited the enzyme. These results may be used in studies of the neuraminidase action mechanism and regulation of its activity.

Catalysis↗
PubMed1990

Autologous bone marrow transplantation for acute myeloid leukemia following in vitro treatment with neuraminidase and monoclonal antibodies.

Although monoclonal antibodies (MoAbs) to CD15, especially PM-81, react with leukemic blasts from the majority of patients with acute myeloid leukemia (AML), a small subset of patients have cells that are CD15 negative or dim. We determined previously that neuraminidase will increase the reactivity of PM-81 with AML blasts, as well as blasts from many patients with acute lymphoblastic leukemia (ALL). In this report, we describe the laboratory results and clinical course of the first patient with AML whose harvested bone marrow was treated with neuraminidase prior to MoAbs and complement treatment. Neuraminidase increased the percentage of the patient's leukemia cells that reacted with PM-81 from 18% to 90% and more than doubled the percentage of AML blasts that were lysed by PM-81 and complement. The patient suffered no acute toxicity, engrafted rapidly, and was transfusion independent by day 21 post-ABMT. This report demonstrates the probable safety and efficacy of pretreatment of bone marrow with neuraminidase, and increases the number of patients with AML or ALL who may benefit from ABMT using marrow purging with MoAb to CD15.

Acute Disease↗
PubMed1990

Monoclonal antibodies against Trypanosoma cruzi neuraminidase reveal enzyme polymorphism, recognize a subset of trypomastigotes, and enhance infection in vitro.

The identification and characterization of two murine mAb (TCN-1 and TCN-2) that react with the neuraminidase of Trypanosoma cruzi is reported. The mAb were identified based on their ability to inhibit enzyme activity and recognize neuraminidase in crude enzyme preparations. TCN-1 and TCN-2 recognized Ag in tissue culture trypomastigotes but not in the amastigotes, epimastigotes, or metacyclic trypomastigotes using immunoblot assays and immunofluorescence. In addition, clones Y-H6, MV-13, and Silvio X-10/4 of T. cruzi revealed a unique banding pattern characteristic of each clone. In Silvio X-10/4, the mAb recognized four distinct bands ranging from 121,000 to 203,000 whereas in Y-H6 and MV-13 they identified bands ranging from 138,000 to 222,000. Characterization of neuraminidase by two-dimensional PAGE revealed the polypeptides that make up the enzyme to have isoelectrical points ranging from 6.55 to 7.30. Immunofluorescence and C-mediated lysis assays showed that the mAb reacted with a subset of trypomastigotes representing 28% of the total parasite population. Functional studies showed that the mAb enhanced infection of cultured cells by trypomastigotes. Our experiments confirm previous findings with polyclonal Ab and are in accordance with the hypothesis that neuraminidase modulates infection through a negative control mechanism.

Animals↗
PubMed1975

Neuraminidase activity of influenza virus-infected cells: localization and properties.

Infection of chick embryo cell (CEC) cultures with influenza virus results in the appearance of neuraminidase activity lost by the cells as a result of cultivation. Neuraminidase activity is associated mainly with the lysomal cell fraction. Different distribution of neuraminidase activity in lysosomes with various densities, different reaction to sodium ethylene diamine tetracetate (EDTA) and differenct optimal pH suggest that at early stages of viral infection the cell enzyme is activated and by the 7th hour of infection viral neuraminidase is synthesized.

Acid Phosphatase↗
PubMed1978

Electrophoretic mobility distributions of normal human T and B lymphocytes and of peripheral blood lymphoblasts in acute lymphocytic leukemia: effects of neuraminidase and of solvent ionic strength.

Human T and B lymphocytes were found to be distinguishable on the basis of electrophoretic mobility, with the T cells having the higher mobility, in agreement with previous reports. The effects of the enzyme neuraminidase on the electrophoretic mobilities of T and B lymphocytes were determined. T lymphocytes showed a greater decrease in electrophoretic mobility after neuraminidase treatment; the relative mobilities of T and B cells were reversed by neuraminidase treatment, and the electrophoretic distinguishability was enhanced. The electrophoretic mobility distributions of lymphoblasts from patients with acute lymphocytic leukemia were found to differ from those of normal cells in their response to neuraminidase treatment and to changes in solution ionic strength. These results imply that the surface structure of the leukemic cells differs from that of either T or B lymphocytes from normal donors.

B-Lymphocytes↗
PubMedDate not supplied

[Immunologic analysis of the antigenic properties of neuraminidase from drift-variants of influenza virus B].

The antigenic features of neuraminidases of several drift variants of influenza B virus were studied by enzyme immunoassay using antiserum to influenza B/USSR/100/83 virus neuraminidase isolated by pronase. Studies using immunosorption and competitive solid-phase enzyme immunoassay showed the presence in the antineuraminidase serum of at least two antibody subpopulations capable to inhibiting the activity of the enzyme and interacting with neuraminidase antigenic determinants: one detecting the antigenic determinant common for B/100/83 and B/Lee/40 viruses, and the other characterizing the antigenic determinant inherent in neuraminidase of B/100/83 virus and enzymes of drift variants isolated in 1970-1986 and lacking in the enzyme of B/Lee/40 virus.

Antibodies, Viral↗
PubMed1978

Influence of the isolation procedure on the structure, neuraminidase and heamagglutinating activities of Sendai virus envelope glycoproteins.

The influence of the isolation procedure of Sendai virus glycoproteins from the virus surface on their neuraminidase and haemagglutinating activities, as well as on some structural properties was studied. These glycoproteins exhibited lower specific neuraminidase and haemagglutinating activities than those of intact virus. Neuraminidase activity was expressed when the glycoproteins were constituted in forms with molecular weights of about 70,000 (monomer), 160,000 (dimer), 300,000 (tetramer) or 600,000 (octamer), whereas haemagglutinating activity was only found for the glycoproteins aggregated in a high mol. wt. (approximately 10(6) daltons) form. The isolated glycoproteins contained two subunits revealed by sodium dodecyl sulphate polyacrylamide gel electrophoresis and three distinct antigenic components revealed by rocket immunoelectrophoresis. Different treatments of the glycoproteins after their isolation altered their structure. Consequently either neuraminidase and haemagglutinating activities were signicantly reduced, or one of these activities was not expressed.

Antigens, Viral↗
PubMedDate not supplied

[Physiochemical properties of purified and virion neuraminidases of the influenza B viruses].

A method for isolation of neuraminidase using pronase has been developed. Purified preparations have been recovered from two influenza B virus strains, B/Mass/3/66 and B/USSR/14/80. Physico-chemical properties of neuraminidases were compared; optimal conditions for the determination of neuraminidase activity of these strains were determined. Strains differences in thermostability, optimal pH, specificity to substrates were established. Neuraminidases, isolated or present in virions, were shown to be identical in enzymatic characteristics but to differ in thermostability.

Chemical Phenomena↗
PubMed1985

[Properties of human chorion neuraminidase].

Some properties of human chorion neuraminidase were studied. Using n-butanol, a solubilized preparation of neuraminidase with specific activity considerably exceeding the initial activity of the chorion homogenate was obtained. The pH-dependence and substrate specificity of the enzyme towards low molecular weight (sialylglycolipids and sialylglycoproteins) native substrates were examined. These properties of solubilized neuraminidase from human chorion were found to be similar to those of the lysosomal enzyme from other animal tissues. The results abtained are consistent with the properties of neuraminidase from native chorion and amniotic fluid cell cultures. Based on the substrate specificity of the solubilized enzyme, it was found that chorion biopsy specimens could be used for prenatal diagnosing of sialidoses and mucolipidoses IV. Some properties of solubilized human chorion beta-galacotosidase were studied.

Chorion↗
PubMed1972

Characterization of the haemagglutinin and neuraminidase antigens of some recent avian type A influenzavirus isolates from Hong Kong.

During 1969 type A influenzaviruses were isolated from three outbreaks of disease among domestic ducks in Hong Kong. The isolates were characterized in haemagglutination inhibition and neuraminidase inhibition tests with antisera to prototype avian and human influenza strains. A/duck/Hong Kong/46/69 and 120/69 contained haemagglutinin and neuraminidase antigens related to those of A/turkey/Wisconsin/66. The neuraminidases of these Hong Kong isolates, like that of turkey/Wisconsin/66, were antigenically closely related to those of human Asian influenzaviruses. A/duck/Hong Kong/826/69 contained haemagglutinin and neuraminidase antigens related to those of chicken/Scotland/59 and tern/South Africa/61, respectively. The duck influenza A isolates represent the first viruses of their antigenic variety to be isolated in South-East Asia. The possible epidemiological significance of the duck/Hong Kong/69 strains is discussed.

Animals↗
PubMed1975

[Neuraminidase neutralizing antibodies in pigs with chronic Erysipelothrix rhusiopathiae infection (author's transl)].

Investigating sera from pigs with chronic E. rhusiopathiae infection relative gamma-globulin values, agglutination titers, and neuraminidase-neutralizing humoral antibodies were determined at the 12th and 15th, 11th and 14th, and 3rd and 6th month after infection. We found increasing gammaglobulin values and increasing neuraminidase neutralizing antibodies but decreasing agglutination titers. Few animals don't have antibodies against neuraminidase and died during the observation period. Furthermore immunodiffusion test demonstrated precipitating lines of antibodies against living E. rhusiopathiae cells and active neuraminidase. No or very weak bands were observed against heat killed cells and heat-inactivated enzyme.

Agglutinins↗