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Results for “NEURAMINIDASE”

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PubMed1984

[Purification of neuraminidase from influenza virus on an immunosorbent].

A procedure for isolation of neuraminidase from influenza virus using the nonionic detergent Triton x-100 was developed. To achieve further purification, the protein mixture was passed through a Sepharose column packed with immobilized antibodies against hemagglutinin. The neuraminidase preparation thus obtained fully retained its enzymatic and antigenic properties and during electrophoretic separation under denaturating conditions gave one protein band.

Animals↗

PubMed1984

Effect of pregnancy plasma, neuraminidase and sialic acid on phytohemagglutinin-induced human lymphocyte response.

The effect of human pregnancy plasma on phytohemagglutinin-(PHA-)induced blastogenesis of lymphocytes from unrelated donors was studied in relation to the sialic acid (N-acetyl-neuraminic acid) content of the plasma. The total sialic acid levels in plasma were found to be elevated during pregnancy as compared with plasma from non-pregnant, normally menstruating control groups (p less than 0.001) and to increase with advancing gestation, reaching peak values in the post-partum period (1-14 days). On the other hand, pregnancy plasma at a concentration of 15% caused a significant suppression of lymphocyte proliferation (p less than 0.05 to p less than 0.001, depending on the stage of gestation). The maximum effect was observed with plasma obtained during the third trimester of pregnancy. The immunosuppressive activity was not detectable after parturition. It was further observed that desialation of both pregnancy and control plasma with neuraminidase diminished lymphocyte response to PHA (p less than 0.05). Addition of free sialic acid (0.1-1.0 mumol/ml) or treatment of the cells with neuraminidase (0.06-1.0 IU/ml) had no effect on lymphocyte transformation under assay conditions. These findings support the hypothesis that an immunosuppressive environment provided by pregnancy plasma could be one of the mechanisms protecting the antigenically alien fetus from maternal immunologic attack. The sialic acid content of maternal plasma did not appear to play a role in the immunosuppressive property of maternal plasma. On the contrary, the presence of plasma-bound sialic acid in the culture medium was found to be necessary for normal lymphocyte reactivity.

Blood Physiological Phenomena↗

PubMed1984

[Mechanism of the modifying effect of neuraminidase of the influenza virus on the development of Rauscher leukemia].

It was established that neuraminidase--an immunosuppressive component of influenza virus--stimulated Rauscher leukemia in BALB/c mice. This effect is connected with earlier manifestation of sensitization to embryonic antigens and the appearance of immature PNL+ cells in spleens of infected mice rather than with immunosuppression. The mechanism of cocarcinogenic effect of viral neuraminidase is discussed.

Agglutination Tests↗

PubMedDate not supplied

[Antitumor effect of a tumor-cell neuraminidase vaccine].

The effect of neuraminidase vaccine of CBA mouse sarcoma cells caused by simian adenovirus SA7 (C8) on growth parameters of transplanted sarcoma in a syngeneic system was studied. Inoculation of the vaccine was found to inhibit tumor growth. This effect was more marked in a group of animals given tumor cells after preliminary vaccination. There was no correlation between tumor growth parameters and cytotoxic activity of spleen cells assesses in the cytotoxicity test by 51Cr release in the groups of vaccinated and control animals. It is concluded that the treatment of tumor cells with neuraminidase increases their immunogenicity. The cytotoxic activity of spleen cells in vaccinated animals appears earlier and persists longer.

Adenoviruses, Simian↗

PubMedDate not supplied

[Radioimmunological analysis of the neuraminidase of influenza virus subtype N2].

Competitive radioimmunoassay in the homologous system using 125I-labeled neuraminidase (NA) of A/Japan/305/57 virus and antibodies to it showed that influenza viruses NA of subtypes H2N2 (A/Singapore/1/57 and A/Tokyo/3/67) and H3N2 (A/Aichi/2/68, A/England/42/72, A/Port Chalmers/1/73, and A/Texas/1/77) had undergone clear antigenic change despite the presence of Japan strain NA determinant. The use of a heterologous system (125I-NA of the Japan strain--antibodies to NA of England/42/72 strain) for the study of the intratype determinant showed the presence of a common determinant in all the strains under study, this determinant being represented dissimilarly, however. Neuraminidase of the Texas strain has a determinant differing from the intratype one, common for the Japan and England viruses.

Animals↗

PubMed1984

Metastasis control by injection of blood lymphocytes cultured with neuraminidase-treated MT/W 449A rat mammary carcinoma.

Inevitable metastatic disease was partially controlled in Wistar/Furth rats after intraperitoneal injection of blood lymphocytes cultured with neuraminidase-treated tumor cells and phytohemagglutinin after amputation of implanted syngeneic MT/W 449A mammary adenocarcinoma. Control of MT/W 449A metastasis was limited to animals with primary tumors weighing less than 700 mg. An optimal 20-25 X 10(6)-lymphocyte dose gave control in 8 of 18 animals (44%). Metastasis control rate was 50% in animals with small primary tumors (less than 250 mg). All animals in different control groups died of metastatic disease, without significant survival differences among overall groups or tumor weight-stratified subgroups. Intraperitoneal injection of neuraminidase-treated tumor cells alone did not control metastatic disease. Cell-mediated 51Cr-release cytotoxicity indexes of test inocula were significantly predictive of longevity and survival.

Animals↗

PubMed1984

[Neuraminidase activity of staphylococci].

141 S. aureus and S. epidermidis strains, isolated from the personnel of obstetric wards by taking smears from the anterior sections of the nose, have been tested for their capacity for neuraminidase production. The test has been carried out by the thiobarbiturate method in a medium with ovomucin added. Neuraminidase activity has been found to be characteristic mostly of S. aureus strains isolated from constant carriers.

Carrier State↗

PubMed1981

Stimulation of chronic lymphatic leukaemia cells by pokeweed mitogen after treatment with neuraminidase-galactose oxidase.

CLL lymphocytes gave a low response upon stimulation with PHA or PWM in 3-day cultures. However, after treatment with neuraminidase-galactose oxidase (NGO), in the presence of PWM, CLL lymphocytes transformed into blasts and incorporated 3H-thymidine in 3-day cultures. This response of CLL lymphocytes was similar to that given by normal lymphocytes to PWM in 3-day cultures. The best stimulation of CLL lymphocytes was achieved when conditioned medium (CM) from normal T lymphocytes was present in PWM cultures. Purified B lymphocytes from CLL (T lymphocytes and monocytes removed) did not respond to PHA or PWM. However, after NGO treatment these cells were stimulated by PWM, but only in the presence of CM. PHA failed to stimulate NGO-treated CLL lymphocytes or purified B lymphocytes. This study shows that CLL lymphocytes, which usually fail to respond to mitogens, can be stimulated by PWM to proliferate after treatment with neuraminidase-galactose oxidase (NGO). This technique of B cell stimulation has been found useful in cytogenetic studies of B cell proliferative disorders.

B-Lymphocytes↗

PubMed1982

Effects of neuraminidase on O2 consumption and release of O2 and H2O2 from phagocytosing human polymorphonuclear leukocytes.

Neuraminidase type X (NMD-type-X, Sigma Chemical Co., St. Louis, Mo.), which is obtained from a further purification of neuraminidase type V (NMD-type-V, Sigma), markedly enhanced the release of O2- and H2O2 from phagocytosing human polymorphonuclear leukocytes (PMN). In contrast, O2 consumption by NMD-type-X-treated PMN was identical to that of untreated PMN. Morphological observations suggested that the enhancement of O2- and H2O2 release was caused by excessive release of the oxygen metabolites into the extracellular medium from incompletely formed phagocytic vacuoles as was observed with cytochalasin-B-treated cells. Our observations are in contrast to the previous reports of Tsan et al. that showed complete inhibition of both O2- and H2O2 release from phagocytosing PMN by the treatment with NMD-type-V.

Cell-Free System↗

PubMed1977

Enhancement and stabilization effect of EDTA on Sendai virus neuraminidase activity.

EDTA was found to enhance, and exert a stabilizing effect on, Sendai virus neuraminidase activity. The effect was dependent on the molecular form of the enzyme and on the nature of the substrate. The "native form" (enzyme bound to the virions) was less influenced than the "mixed form" (enzyme separated from the surface of virions together with other glycoproteins), which in turn was less influenced than the purified enzyme. On the other hand, the stimulation by EDTA of neuraminidase-induced hydrolysis of fetuin was higher than that of ovomucoid. The kinetic data obtained indicate that EDTA modifies the enzyme in such a manner that the affinity of the substrate for the enzyme is increased.

Calcium↗

PubMed1981

Use of a synthetic hapten in the demonstration of the Thomsen-Friedenreich (T) antigen on neuraminidase-treated human red blood cells and lymphocytes.

Using an artificial T hapten, we have confirmed that human sera contain agglutinins for neuraminidase-treated red blood cells (N'RBC), specific for the disaccharide beta DGal(1 leads to 3)alpha DGalNAc. Further, we have shown that these agglutinins are antibodies largely of the IgM subclass that bind equally to neuraminidase-treated lymphocytes (N'lymphocytes). The anti-T antibody in human serum is cytotoxic for N'RBC in complement fixation assays. The synthetic hapten has biologic activity as shown in inhibition experiments and by the specificity of a rabbit antibody raised to the hapten for the naturally occurring antigen on N'RBC and N'lymphocytes. An immunoadsorbent prepared from the hapten was used to obtain biologically active antibodies from human serum with specificity for the naturally occurring antigen.

Agglutinins↗

PubMed1981

Neuraminidases of Bacteroidaceae die neuraminidasen von bacteroidaceen.

Neuraminidases can be detected in members of the anaerobic gram-negative non-sporing rods (Bacteroidaceae), especially in the genus Bacteroides. B. fragilis, the most virulent species, has the highest neuraminidase activity, while the other intestinal species exhibit markedly lower activities or the enzyme is completely absent. Members of the Bacteroides oralis group, so far investigated, degrade only substrates of lower molecular weight.

Anaerobiosis↗

PubMed1981

Mucolipidosis I (acid neuraminidase deficiency). Three cases and delineation of the variability of the phenotype.

Isolated deficiency of the lysosomal hydrolase acid neuraminidase results in multisystem storage of sialic acid-rich oligosaccharides. Wide phenotypic diversity occurs within this biochemical defect. We studied three cases of an infantile form of mucolipidosis I in which the phenotype is dominated by severe Hurloid features. These patients excreted excessive amounts of sialic acid-rich oligosaccharides in their urine, and storage of similar compounds was shown in tissues and cultured fibroblasts. Cultured fibroblasts demonstrated an isolated deficiency of acid neuraminidase; beta-galactosidase levels were normal.

Child↗

PubMed1980

[Local and systemic antibody response after vaccination with 3 different types of vaccines against influenza. II. Neuraminidase inhibiting antibodies (author's transl)].

Three types of inactivated bivalent influenza vaccines containing the A/Victoria/3/75 (A-Component) and B/Hongkong/8/73 (B-Component) antigens either as aluminium salt adsorbed whole virus (AlorbatTM, "A") and split virus (Begrivac STM, "B") or as fluid subunit (SandovacTM, "S") products were given to immunological homogeneous study groups of adults and children. The immune response was compared between the groups on the basis of systemic and local neuraminidase inhibiting (NI) antibody induction 4 weeks after vaccination. In evaluation of the serologic results the sea and nasal washings were tested in the ESSEN-NIT with use of the A/Eq(eq1)-VIC (N 2) recombinant antigen and the B/Hong kong/8/73 strain. The number of individuals (adults plus children) evaluated ranged from 33 to 35 per vaccine. The percentages of persons greater than or equal to 16 years old showing a significant (1.5 x, or greater) response to the A-component were 100%, 96% and 90%, respectively for the vaccine "A", "S" and "B"; the values for the B-component were 70%, 79% and 74%, respectively. The observed conversion rates in children ranged 70% to 100%. Local antibody formation was less pronounced, the percentages of significant conversions were scattered over a wide range from 13% to 80% yielding slightly better responses in children than adults. Taken altogether, the results of the trial indicate that the 3 vaccines studied induced appreciable concentrations of systemic antibodies to the neuraminidase antigen without significant differences between the vaccine types. This potency of the influenza vaccines to induce high titers of NI antibodies thus provides another marker for their immunogenicity and conceivably for their efficacy.

Adolescent↗

PubMed1978

A neuraminidase in duck embryo rabies vaccine.

While studying variations amony immunizing potentials of rabies vaccines, we were led to consider the possibility that the antigen in the vaccine derived from duck embryos may have been degraded by enzymes arising from host tissues. Such an enzyme, a neuraminidase, was found in duck embryo rabies vaccine through the application of a periodate-linked thiobarbituric acid assay. This acitvity could not be found in two other rabies vaccines derived from tissue cultures. We have thus concluded that there is a strong possibility that a modified antigen is present in duck embryo vaccine. In addition, the injection of this vaccine will introduce a neuraminidase which may produce localized effects in the tissues of the recipient.

Animals↗

PubMed1980

Necrotising enterocolitis and neuraminidase-producing bacteria.

In 9 out of 26 newborns with necrotising enterocolitis (NEC) exposure of the Thomsen-cryptantigen (T-antigen), probably due to the action of circulating bacterial neuraminidase, was demonstrated on red blood cells. The serological titres seemed to correlate with the clinical course of the disease. Neuraminidase-producing clostridia were isolated in two of the patients. Reaction between the exposed T-antigen and anti-T-agglutinins, normally present in human blood, may lead to difficulties during blood transfusion. This potential transfusion hazard is best avoided by routine T-antigen-tests and by transfusion of packed or washed red blood cells to T-antigen-positive patients.

Antibody Specificity↗

PubMedDate not supplied

Standardization of assays of neuraminidase and its antibody.

The effect of various factors on the reproducibility of neuraminidase and NI antibody assays has been investigated. These factors include the substrate, strain of virus, nature of virus, i.e. whole, subunit or recombinant, temperature and pH. In assaying antibody levels the challenge virus should be standardized by a method other than optical density. It is recommended that a collaborative study should be set up to establish an international standard for neuraminidase and that this should incorporate a comparison of different methods.

Antibodies, Viral↗

PubMed1995

A sialic acid-derived phosphonate analog inhibits different strains of influenza virus neuraminidase with different efficiencies.

A phosphonate analog of N-acetyl neuraminic acid (PANA) has been designed as a potential neuraminidase (NA) inhibitor and synthesized as both the alpha (ePANA) and beta (aPANA) anomers. Inhibition of type A (N2) and type B NA activity by ePANA was approximately a 100-fold better than by sialic acid, but inhibition of type A (N9) NA was only ten-fold better than by sialic acid. The aPANA compound was not a strong inhibitor for any of the NA strains tested. The crystal structures at 2.4 A resolution of ePANA complexed to type A (N2) NA, type A (N9) NA and type B NA and aPANA complexed to type A (N2) NA showed that neither of the PANA compounds distorted the NA active site upon binding. No significant differences in the NA-ePANA complex structures were found to explain the anomalous inhibition of N9 neuraminidase by ePANA. We put forward the hypothesis that an increase in the ePANA inhibition compared to that caused by sialic acid is due to (1) a stronger electrostatic interaction between the inhibitor phosphonyl group and the active site arginine pocket and (2) a lower distortion energy requirement for binding of ePANA.

Binding Sites↗