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PubMed1987

The patient with combined deficiency of neuraminidase and 21-hydroxylase.

To investigate the possibility that deletion en block in the HLA region had caused the combined deficiency of neuraminidase and 21-hydroxylase in a female patient, genetic markers on the short arm of chromosome 6 were examined in the patient and her parents, and 21-hydroxylase genes of the patient were analyzed by the Southern blot technique. The affected "extended haplotype" identical by descent might have been recombined at two sites, between HLA-A and C and between HLA-DQ and GLO. This suggests that the neuraminidase gene is mapped between HLA-A and GLO. Southern blot analysis revealed the existence of two 21-hydroxylase genes, so that we found no evidence to support the possibility that deletion en bloc in the HLA class III region had caused the combined deficiency of neuraminidase and 21-hydroxylase.

Adrenal Hyperplasia, Congenital↗
PubMed1985

The infantile form of sialidosis type II associated with congenital adrenal hyperplasia: possible linkage between HLA and the neuraminidase deficiency gene.

The possible genetic linkage between HLA and neuraminidase deficiency was studied in a female patient with combined abnormalities of the infantile form of sialidosis type II and congenital adrenal hyperplasia caused by 21-hydroxylase deficiency, and six members of her family. Her parents were consanguineous. The patient has the homozygous HLA haplotypes, TS-1, Cw3, DRw9. Four of the tested family members, including a distant male relative with congenital adrenal hyperplasia, were heterozygous of this HLA complex, and the neuraminidase activities in their skin fibroblasts and/or lymphocytes showed values between those of the patient and controls (25-48%), suggesting a carrier state of sialidosis. This indicates that the neuraminidase deficiency gene, similar to the 21-hydroxylase deficiency gene, is closely linked to the HLA genotype and is located on chromosome 6.

Adrenal Hyperplasia, Congenital↗
PubMed1985

Effect of poly-L-lysine and neuraminidase on the infectivity of Trypanosoma cruzi in cultured HeLa cells.

The percentage of parasitisation and index of adherence of Trypanosoma cruzi has been studied when host HeLa cells or metacyclic forms were pretreated with neuraminidase or with poly-L-lysine. The percentage of parasitisation was significatively reduced (P less than or equal to 0.001) when cells were pretreated with poly-L-lysine while pretreatment with neuraminidase caused no apparent effects. On the other hand, the adherence of the metacyclic forms pretreated with poly-L-lysine or neuraminidase was significantly higher than that of the control group.

Adhesiveness↗
PubMed1985

Characterization of a 1980-swine recombinant influenza virus possessing H1 hemagglutinin and N2 neuraminidase similar to that of the earliest Hong Kong (H3N2) virus.

A recombinant (H1N2, formerly Hsw 1N2), A/swine/Ehime/1/80 was found to possess antigenic, biological and genomic characteristics different from those of a previous A/swine/Kanagawa/2/78 (H1N2) strain. Five monoclonal antibodies to A/NJ/8/76 definitely differentiated the hemagglutinin molecules of the former virus from the latter, showing that these viruses differed, at least, at two antigenic determinants. Neuraminidase-inhibition tests with monoclonal antibodies to different H2N2 and H3N2 viruses revealed that the A/swine/Ehime/1/80 strain contained a neuraminidase very similar to that of the late human Asian (H2N2) and the earliest Hong Kong (H3N2) viruses. Growth comparison of swine and human isolates indicated that A/swine/Ehime/1/80 and A/swine/Shizuoka/1/78 (H1N1) failed to grow at 42 degrees C, while A/swine/Kanagawa/2/78 and its possible parental virus, A/swine/Kanagawa/4/78 (H1N1) replicated efficiently at this stringent temperature. These results revealed that the viruses having growth characteristics similar to those of avian influenza virus were present in the swine population. RNA analysis by oligonucleotide mapping suggested that A/swine/Ehime/1/80 may be a recombinant between A/swine/Shizuoka/1/78-like and A/Aichi/2/68 (H3N2)-like viruses. To further determine the gene constellation of this recombinant virus, DNA-RNA hybridization was performed by using DNA segments complementary for swine (H1N1) virus RNA and the entire RNAs of three viruses. The molecular hybridization could define the genomic composition of the recombinant, indicating that only the neuraminidase gene of this virus is derived from the earliest Hong Kong (H3N2)-like virus and remaining seven genes from swine (H1N1) virus.

Animals↗
PubMed1988

Monoclonal antibodies against avian paramyxovirus-3: antigenic mapping and functional analysis of the haemagglutinin-neuraminidase protein and the characterization of nonspecific monoclonal antibodies.

Sixteen monoclonal antibodies (Mabs) which immunoprecipitated the haemagglutinin neuraminidase (HN) of chorio-allantoic membrane-grown avian paramyxovirus-3 (PMV-3) of British turkeys were produced. Thirteen were PMV-3 specific. Three were nonspecific because they also bound to other viral proteins and to bovine kidney cells treated with neuraminidase enzyme or infected with influenza virus. The thirteen specific Mab defined four antigenic regions A-D by competition and variant selection assays. Region A was subdivided into five epitopes and region B into two epitopes. The thirteen Mab neutralized and were active in haemagglutination inhibition (HI) and twelve were active in haemolysis inhibition (HLI) tests. Neuraminidase inhibition (NI) was epitope-dependent. Mabs to five of the epitopes A1, A2, A3, A5, and C bound to the 1981 British turkey isolates but not the 1968 American turkey isolate. The Mab to epitope A4 bound to both viruses. The Mabs to epitopes B1, B2, and D also bound to a parakeet isolate of PMV-3 which was the third PMV-3 tested. The Mab to B2 gave identical titres to all three viruses and had HI, HLI, and NI activities. This made it a potential diagnostic reagent for avian PMV-3 viruses. One of the nonspecific Mabs bound to lactose-like moieties as reported on influenza virus and one to maltose-like moieties as on retroviruses. Immunoglobulin from all three nonspecific Mab had some HI activity.

Animals↗
PubMed1977

Preparation-conditioned changes of the antigenicity of influenza virus neuraminidases.

The influenza virus strains A/Sing/1/57 (H2N2), A/Bel/42 (H0N1) and A/Bel/42 (HO)-A/Sing/1/57 (N2) were treated with bromelain under reducing conditions and with reducing agent alone, and the antigenicity of the neuraminidase (NA) of intact virus and of the split products was tested comparatively. It was found that the antigenicity of NA was influenced quantitatively and qualitatively by the preparation procedure. Antineuraminidase (AN) antibodies obtained after vaccination of guinea pigs with intact virus and with split products differed in their cross-reactivity with heterologous neuraminidases. In several cases, the quantity of AN antibody formation depended on the hemagglutinin (HA) dose present in the vaccines. The N2 NA on the recombinant virus was significantly more sensitive to treatment with reducing agent than was the N2 NA on the parent virus. AN antibodies directed against N2 NA on the recombinant differed qualitatively from that directed against N2 NA of parent virus. The results warrant the conclusion that the antigenicity of isolated NA or of NA on recombinant virus can differ from that of the NA on intact homologous virus and that such alterations could influence the determination of antigenic relationship between neuraminidases.

Animals↗
PubMed1976

Absence of neuraminidase from influenza C virus.

Influenza C viruses did not possess neuraminidase activity when examined using either fetuin or sialyllactose as substrate. Purified preparations of influenza C virus inhibited hemagglutination by NWS hemagglutinin. The hemagglutination inhibiting activity was abolished by treatment of influenza C virus with neuraminidase. These findings indicated the absence of neuraminidase activity on influenza C virus particles.

Hemagglutination, Viral↗
PubMed1989

Influenza A virus enhances IgE-mediated histamine release from human basophil leukocytes. Examination of the effect of viral neuraminidase and haemagglutinin.

Histamine release caused by anti-IgE was examined in leukocyte suspensions from 10 healthy individuals. Influenza A virus was found to enhance the histamine release but did not release histamine per se. When monoclonal antibodies directed against the viral neuraminidase were included in the samples, the potentiating effect of the virus was completely abolished. The same occurred using a neuraminidase inhibitor. However, monoclonal antibodies directed against the viral haemagglutinin also abolished the potentiation. A binding of virus to the basophil cell surface by haemagglutinin therefore seems to be necessary for the viral neuraminidase to cause potentiation of mediator release.

Antibodies, Anti-Idiotypic↗
PubMedDate not supplied

Neuraminidase decreases in vitro adherence of slime-forming coagulase-negative staphylococci to biosynthetic ovine collagen vascular graft.

Vascular prosthetic graft infection is a major complication of vascular surgery that starts with adhesion of the microorganism to the graft. Because slime-forming microorganisms are the major causative agents in graft infection, the goals of investigators in this study were (1) to investigate the bacterial adherence of slime-forming and non-slime-forming coagulase-negative staphylococci (CNS), and (2) to determine the role of neuraminidase (NANase) in bacterial adherence to the biosynthetic ovine collagen graft. Human plasma was instilled and incubated at 37 degrees C in preparation for fibrin deposition of grafts. After 48 hours, incubation grafts were drained and inoculated with slime-forming and non-slime-forming CNS in tryptic soy broth in the presence and in the absence of neuraminidase. After 24 hours of incubation at 36 degrees C, grafts were vortexed and cultured for colony count. Bacterial counts were expressed as total colony-forming units per longitudinal centimeter of the graft. Slime-forming CNS had greater affinity to the collagen graft compared with non-slime-forming CNS (P<.05). Adherence of slime-forming CNS was impaired by NANase treatment (P<.001). NANase treatment of patients with non-slime-forming CNS did not change adherence to the graft (P>.05). Results show that slime plays an important role in the pathogenesis of vascular graft infection. Adherence of slime-forming CNS can be decreased through the administration of NANase. This may have implications for the development of neuraminidase-embedded vascular grafts designed to reduce the occurrence of biomaterial-related infection.

Animals↗
PubMed1978

Neuraminidase activity of NAG vibrios and of some representatives of the intestinal group of bacteria.

It was studied 203 strains of NAG vibrios and 71 strains of different enterobacteria for the ability to produce neuraminidase. The most frequent neuraminidase producers were found among the strains isolated from humans (99 strain of 131). There was no correlation between neuraminidase production and other properties of the vibrios. The examined strains of the family Enterobacteriaceae did not produce the enzyme.

Aeromonas↗
PubMed1998

Neuraminidase injected into the cerebrospinal fluid impairs the assembly of the glycoproteins secreted by the subcommissural organ preventing the formation of Reissner's fiber.

Neuraminidase was injected into the cerebrospinal fluid of normal rats to investigate the assembly and fate of the desialylated Reissner's fiber glycoproteins. It was established that a single injection of neuraminidase cleaved the sialic acid residues of the Reissner's fiber glycoproteins that had been assembled before the injection, and of the molecules that were released over a period of at least 4 h after the injection. These desialylated glycoproteins underwent an abnormal assembly that led to the formation of spheres instead of a fiber. The number of these spheres increased during the 4-h period following the injection, indicating that neuraminidase did not prevent the secretion of the Reissner's fiber glycoproteins into the cerebrospinal fluid. The spheres remained attached to the surface of the subcommissural organ and became intermingled with infiltrating cells, many of which were immunocytochemically identified as macrophages. The latter were seen to contain immunoreactive Reissner's fiber material. It is concluded that the desialylated Reissner's fiber glycoproteins forming the spheres underwent an in situ degradation by macrophages, thus resembling the normal process undergone by the Reissner's fiber glycoproteins reaching the massa caudalis.

Animals↗
PubMed1998

Evaluation of recombinant A/Victoria/3/75 (H3N2) influenza neuraminidase mutants as potential broad-spectrum subunit vaccines against influenza A.

Current influenza vaccines require repeated administration for long-term protection. Failure to develop broad-spectrum vaccines may be attributed to the chronic presentation of hypervariable, immunodominant epitopes displayed on the viral surface that keep the immune response somewhat fixed and limited by suppression of broadly neutralizing, low-titered antibodies. To test this hypothesis, we have attempted to dampen the immunogenicity of variable epitopes and potential immunodominant domains of the A/Victoria/3/75 (H3N2) neuraminidase by site-directed mutagenesis. The results suggest that the neuraminidase structure is extremely flexible, since many substitution combinations were tolerated, and constitute proof-of-principle that the antigenicity of this protein can be modulated to a large extent. However, mice immunized with neuraminidase mutants containing multiple amino acid substitutions showed a reduced protection rate against heterologous virus in comparison with the reference groups.

Animals↗
PubMed2005

Influenza treatment with neuraminidase inhibitors: cost-effectiveness and cost-utility in healthy adults in the United Kingdom.

We assessed the cost-effectiveness and cost-utility of treating influenza with neuraminidase inhibitors (oseltamivir and zanamivir) from a health care payer's and societal perspective in the United Kingdom. A simulation model was developed to predict morbidity and mortality due to influenza and its specified complications, comparing neuraminidase inhibitors with usual care in an otherwise healthy adult population. Robustness of the results was tested by one-way and multiway as well as probabilistic sensitivity analyses. Treatment with either neuraminidase inhibitor results in reduced morbidity and faster return to normal activities. However, oseltamivir dominates zanamivir in cost-utility analysis due to its lower costs. Comparing oseltamivir with usual care, the costs are pound14.36 per day of normal activity gained and pound5,600 per quality-adjusted life-year gained from the healthcare payer perspective. Oseltamivir dominates usual care from the societal perspective. Treatment with oseltamivir is a cost-effective strategy for otherwise healthy adults in the UK from both the healthcare payer and societal perspective.

Acetamides↗
PubMed2006

Structural analysis of a designed inhibitor complexed with the hemagglutinin-neuraminidase of Newcastle disease virus.

Viruses of the Paramyxoviridae family are the leading cause of respiratory disease in children. The human parainfluenza viruses (hPIV) are members of the Paramyxovirinae subfamily, which also includes mumps virus, Newcastle disease virus (NDV), Sendai virus (SV) and simian type 5 virus (SV5). On the surface of these viruses is the glycoprotein hemagglutinin-neuraminidase (HN), which is responsible for cell attachment, promotion of fusion and release of progeny virions. This multifunctional nature of HN makes it an attractive target for the development of inhibitors as a treatment for childhood respiratory diseases. Here we report the crystal structure of NDV HN in complex with a derivative of 2-deoxy-2,3-dehydro-N-acetylneuraminic acid, Neu5Ac2en, that has a functional group designed to occupy a large conserved binding pocket around the active site. The purpose of this study was to examine the effect of a bulky hydrophobic group at the O4 position of Neu5Ac2en, given the hydrophobic nature of the binding pocket. This derivative, with a benzyl group added to the O4 position of Neu5Ac2en, has an IC(50) of approximately 10 microM in a neuraminidase assay against hPIV3 HN. The IC(50) value of the parent compound, Neu5Ac2en, in the same assay is approximately 25 microM. These results highlight the striking difference between the influenza neuraminidase and paramyxovirus HN active sites, and provide a platform for the development of improved HN inhibitors.

Crystallography, X-Ray↗
PubMed1980

Accessibility of plasma membrane sialoglycoconjugates of Novikoff tumor cells to exogenous neuraminidase and proteases.

Plasma membrane glycoconjugates of Novikoff tumor cells were radioactively labeled by oxidation with NaIO4 followed by reduction with NaB3H4 Submission of the radioactively labeled glycoconjugates to polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate followed by fluorography revealed the presence of at least ten major glycoproteins and a glycolipid fraction. The glycolipid fraction contained 34% of the cell-surface radioactive label. Pretreatment of cells with neuraminidase from Vibrio cholerae reduced radioactive labeling of the glycoproteins by 71% and that of the glycolipids by 39%. Sequential treatment of cells with papain and neuraminidase further reduced radioactive labeling of the glycolipid fraction, indicating that resistance of this fraction to the hydrolytic action of neuraminidase was determined, at least in part, by steric factors. Incubation of cells with papain resulted in extensive degradation of most of the radioactively labeled glycoproteins with the exception of a subset of glycoproteins having apparent molecular weights of 48 000 +/- 5000. Trypsin was more selective, degrading three glycoproteins having apparent molecular weights of 200 000, 140 000 and 37 000.

Animals↗
PubMed1983

Differential effect of neuraminidase-treatment on the surface charge-associated properties of rat reticulocytes and erythrocytes. Studies by partitioning in two-polymer aqueous phases.

Rat reticulocytes undergo charge-associated surface changes, detectable by cell partitioning in charged dextran-poly(ethylene glycol) aqueous phase systems, as they become mature erythrocytes. Young reticulocytes have a lower partition coefficient, i.e., quantity of cells in the top phase as a percentage of total cells added, than do mature erythrocytes. Sialic acid is the main charge-bearing group on red blood cells and, in the case of the rat, most of the sialic acid can be removed by treatment of the cells with neuraminidase (Vibrio cholerae). By combining isotopic 59Fe-labeling of reticulocytes with countercurrent distribution of the entire red blood cell population in charged dextran-poly(ethylene glycol) aqueous phases we have now studied the relative effect of neuraminidase-treatment on rat reticulocytes and mature erythrocytes. It was found that neuraminidase-treatment (a) does not eliminate surface differences, detectable by partitioning, between rat reticulocytes and erythrocytes and (b) reduces the partition coefficient of mature erythrocytes to a greater extent than the partition coefficient of reticulocytes indicating a differential effect of this enzyme on the two cell populations.

Animals↗
PubMed1983

The effect of neuraminidase on the relative surface charge-associated properties of rat red blood cells of different ages.

Approx. 70% of the sialic acid on the rat erythrocyte surface is susceptible to cleavage by neuraminidase (Vibrio cholerae). Neuraminidase treatment results in a reduction in the partition coefficient (K) of the red cells in a charged dextran-poly(ethylene glycol) aqueous phase system and in the electrophoretic mobility of the cells. Countercurrent distribution of rat neuraminidase-treated erythrocytes, containing 59Fe-labeled mature red cells of distinct age, indicates that (a) the electrophoretic mobilities of red cells in different cavities along the extraction train increase with increasing K, as is the case with untreated erythrocytes, and (b) the cell age-related differences in surface charge-associated properties are neither eliminated nor altered by the enzyme action.

Animals↗
PubMed1975

Characterization of human alpha-galactosidase A and B before and after neuraminidase treatment.

It has been previously reported that following neuraminidase treatment alpha-galactosidase A is converted into the B form, as revealed by electrophoresis. By a variety of techniques such as isoelectrofocusing, DEAE-chromatography and by enzyme kinetic parameters, no conversion of alpha-galactosidase A into B, or the reverse, could be detected after neuraminidase treatment. Only an apparent transformation of alpha-galactosidase A into B was revealed by Cellogel electrophoresis. In addition, a discrepancy was noticed between the pattern of electrophoretic migration on starch gel and Cellogel and the net electrical charges of the two alpha-galactosidases as deduced by isoelectrofocusing and DEAE-cellulose. Neuraminidase treatment did not affect the activity of alpha-galactosidase A towards the natural substrate, ceramidetrihexoside, but the activity of alpha-galactosidase B decreased by about 30% under the same conditions. The two forms of alpha-galactosidases A and B used in this study were extensively purified by classical procedures.

Animals↗