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Query: UMLS:C0267964 (PAA)
 2,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A comparison of two precipitation methods of IgY from normal hen eggs was made. For method I the precipitation agent is represented by PEG 6000, and for method II by organic solvents. The comparative study of some parameters (protein concentration, ovalbumin content, presence of non-specific inhibitors, PAA-gel electrophoresis) shows that method I is more efficient and more convenient than method II. Using this method, we isolated and characterized IgY preparations from hens immunized with circulating influenza virus strains: A/Singapore/6/86 (H1N1), A/Shanghai/11/87 (H3N2) B/Beijing/1/87 and B/Yamagata/16/88 These viral IgY antibody preparations are homogeneous, lacking anti-host cell antibodies and non-specific inhibitors. Their NI titres and HI titres are higher than those found in the sera of immunized birds.
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PMID:Isolation and characterization of egg yolk antibodies IgY from hens immunized with different influenza virus strains. 182 Nov 63

CBA/N mice bearing a chromosome X linked immunological deficiency (Xid) cannot respond to type 2 thymus independent antigens (TI-2). However, when their spleen cells are in vitro simultaneously stimulated by both a TI-2 (Fluorescein conjugated polyacrylamide, Flu-PAA) antigen and a type 1 thymus independent (Trinitrophenyl conjugated Brucella abortus, TNP-BA) antigen, their capacity to respond to the TI-2 antigen is recovered. On the contrary, thymus dependent (TD) Sheep red blood cells (SRBC) antigen did not produce any significant increase of the anti-TI-2 response.
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PMID:[Recovery of the in vitro reactivity of splenic cells of CBA/N mice toward type 2 thymus-independent antigens]. 643 90

A model system was developed to study the role of cell surface oligosaccharides in cytotoxicity mediated by natural killer (NK) cells. Polymeric glycoconjugates Glyc-PAA-PE and Glyc-PAA(Flu)-PE (where Glyc is the 3-aminopropyl Le(x) residue, PAA is the poly(N-2-hydroxyethylacrylamide) matrix, Flu is the residue of a fluorescein derivative, and PE is the phosphatidylethanolamine residue) were synthesized, and their association with the membranes of living K562 cells was studied.
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PMID:[Incorporation of neoglycolipids into K562 cells. Model for the study of carbohydrate dependent lysis of target cells by natural killer cells]. 961 65

Interspecies transmission of influenza A viruses circulating in wild aquatic birds occasionally results in influenza outbreaks in mammals, including humans. To identify early changes in the receptor binding properties of the avian virus hemagglutinin (HA) after interspecies transmission and to determine the amino acid substitutions responsible for these alterations, we studied the HAs of the initial isolates from the human pandemics of 1957 (H2N2) and 1968 (H3N2), the European swine epizootic of 1979 (H1N1), and the seal epizootic of 1992 (H3N3), all of which were caused by the introduction of avian virus HAs into these species. The viruses were assayed for their ability to bind the synthetic sialylglycopolymers 3'SL-PAA and 6'SLN-PAA, which contained, respectively, 3'-sialyllactose (the receptor determinant preferentially recognized by avian influenza viruses) and 6'-sialyl(N-acetyllactosamine) (the receptor determinant for human viruses). Avian and seal viruses bound 6'SLN-PAA very weakly, whereas the earliest available human and swine epidemic viruses bound this polymer with a higher affinity. For the H2 and H3 strains, a single mutation, 226Q-->L, increased binding to 6'SLN-PAA, while among H1 swine viruses, the 190E-->D and 225G-->E mutations in the HA appeared important for the increased affinity of the viruses for 6'SLN-PAA. Amino acid substitutions at positions 190 and 225 with respect to the avian virus consensus sequence are also present in H1 human viruses, including those that circulated in 1918, suggesting that substitutions at these positions are important for the generation of H1 human pandemic strains. These results show that the receptor-binding specificity of the HA is altered early after the transmission of an avian virus to humans and pigs and, therefore, may be a prerequisite for the highly effective replication and spread which characterize epidemic strains.
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PMID:Early alterations of the receptor-binding properties of H1, H2, and H3 avian influenza virus hemagglutinins after their introduction into mammals. 1095 51

Fluorescein labeled carbohydrate (Glyc) probes were synthesized as analytical tools for the study of cellular lectins, i.e. SiaLe(x)-PAA-flu, Sia2-PAA-flu, GlcNAc2-PAA-flu, LacNAc-PAA-flu and a number of similar ones, with PAA a soluble polyacrylamide carrier. The binding of SiaLe(x)-PAA-flu was assessed using CHO cells transfected with E-selectin, and the binding of Sia2-PAA-flu was assessed by COS cells transfected with siglec-9. In flow cytometry assays, the fluorescein probes demonstrated a specific binding to the lectin-transfected cells that was inhibited by unlabeled carbohydrate ligands. The intense binding of SiaLe(x)-PAA-3H to the E-selectin transfected cells and the lack of binding to both native and permeabilized control cells lead to the conclusion that the polyacrylamide carrier itself and the spacer arm connecting the carbohydrate moiety with PAA did not contribute anymore to the binding. Tumors were obtained from nude mice by injection of CHO E-selectin or mock transfected cells. The fluorescent SiaLe(x)-PAA-flu probe could bind to the tumor sections from E-selectin positive CHO cells, but not from the control ones. Thus, these probes can be used to reveal specifically the carbohydrate binding sites on cells in culture as well as cells in tissue sections. The use of the confocal spectral imaging technique with Glyc-PAA-flu probes offered the unique possibility to detect lectins in different cells, even when the level of lectin expression was rather low. The confocal mode of spectrum recording provided an analysis of the probe localization with 3D submicron resolution. The spectral analysis (as a constituent part of the confocal spectral imaging technique) enabled interfering signals of the probe and intrinsic cellular fluorescence to be accurately separated, the distribution of the probe to be revealed and its local concentration to be measured.
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PMID:Fluorescent carbohydrate probes for cell lectins. 1160 44

Synthetic sialic acid-containing macromolecules inhibit influenza virus attachment to target cells and suppress the virus-mediated hemagglutination and neutralize virus infectivity in cell culture. To test the protective effects of attachment inhibitors in vivo, mice were infected with mouse-adapted influenza virus A/Aichi/2/68 (H3N2) and treated with synthetic polyacrylamide-based sialylglycopolymer PAA-YDS bearing moieties of (Neu5Acalpha2-6Galbeta1-4GlcNAcbeta1-2Manalpha1)2-3,6Manbeta1-4GlcNAcbeta1-4GlcNAc. Single intranasal inoculations with PAA-YDS 30 min before or 10 min after infection increased the survival of mice (P<0.01). Multiple treatments with aerosolized PAA-YDS on days 2-5 post infection also increased survival (P<0.01), alleviated disease symptoms, and decreased lesions in the mouse lungs. These data suggest that synthetic polyvalent inhibitors of virus attachment can be used for prevention and treatment of influenza.
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PMID:Polymeric inhibitor of influenza virus attachment protects mice from experimental influenza infection. 1207 64

A comparative study of the hemagglutinin (HA) receptor binding site (RBS) of a number of H13 influenza viruses isolated from Laridae family of birds (gulls) and other influenza viruses obtained from the Anatidae family (ducks) was conducted. The affinity of all viruses to alpha N-acetylneuraminic acid (Neu5Ac alpha), 3'sialyllactose (3'SL), and sialylglycopolymers bearing 3'-sialyl(N-acetyllactosamine) (3'SLN-PAA), [Neu5Ac alpha(2-3)Gal beta(1-4)][-Fuc alpha(1-3)]GlcNAc beta (SLe(x)-PAA), and [Neu5Ac alpha(2-3)Gal beta(1-3)][-Fuc alpha(1-4)]GlcNAc beta (SLe(a)-PAA), was determined. The last three polymer glycoconjugates were synthesized for determining the contribution of carbohydrate chains after the galactose link to the binding with the receptor. The difference in affinity between 3'SL and Neu5Ac alpha in all studied H13 viruses is small, which indicates a less significant role of the galactose moiety in the binding to the receptor. The results of virus binding with polymer sialylglycoconjugates indicates that the method of linking, the third monosaccharide moiety, and the presence of an extra fucose substitute in this moiety may influence the binding considerably. For viruses isolated from ducks, the suitable polymer is SLe(a)-PAA (i.e., a 1-3 linkage between galactose and glucosamine is optimal). This finding is in accord with the data that H13 viruses isolated from the gulls differ based on their ability to interact with polymer sialylglycoconjugates. The affinity to all three polymers is uniform, and the presence of GlcNAc-linked fucose does not prevent the binding. A comparative analysis of six sequenced HA H13 viruses and other subtype viruses showed presence of substantial differences in the composition of amino acids of this region in H13 viruses.
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PMID:Differences between HA receptor-binding sites of avian influenza viruses isolated from Laridae and Anatidae. 1457 35

Natural killer (NK) cell recognition of influenza virus-infected cells involves hemagglutinin (HA) binding to sialic acid (SA) on activating NK receptors. SA also acts as a receptor for the binding of influenza virus to its target host cells. The SA binding properties of H3N2 influenza viruses have been observed to change during circulation in humans: recent isolates are unable to agglutinate chicken red blood cells and show reduced affinity for synthetic glycopolymers representing SA-alpha-2,3-lactose (3'SL-PAA) and SA-alpha-2,6-N-acetyl lactosamine (6'SLN-PAA) carbohydrates. Here, NK lysis of cells infected with human H3N2 influenza viruses isolated between 1969 and 2003 was analyzed. Cells infected with recent isolates (1999 to 2003) were found to be lysed less effectively than cells infected with older isolates (1969 to 1996). This change occurred concurrently with the acquisition of two new potential glycosylation site motifs in HA. Deletion of the potential glycosylation site motif at 133 to 135 in HA1 from a recent isolate partially restored the agglutination phenotype to a recombinant virus, indicating that the HA-SA interaction is inhibited by the glycosylation modification. Deletion of either of the recently acquired potential glycosylation sites from HA led to increased NK lysis of cells infected with recombinant viruses carrying modified HA. These results indicate that alterations in HA glycosylation may affect NK cell recognition of influenza virus-infected cells in addition to virus binding to host cells.
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PMID:Alterations in receptor binding properties of recent human influenza H3N2 viruses are associated with reduced natural killer cell lysis of infected cells. 1767 Aug 34

An estimated $1 billion was lost in decontaminating areas exposed to anthrax in the 2001 attacks. To counter the threat of biological attacks, an effective 'green' decontaminant is vital to minimize the consequences of such attacks. The objective of our research was to study the ability of glycoconjugate ligands to decontaminate Bacillus cereus spores on hard surfaces. Polyvalent glycoconjugates (also known as neoglycoconjugates) were tested during decontamination of B. cereus spores. Resulting colony forming units (CFU) of viable spores were a direct evidence of glycoconjugate decontamination efficacy. Our results indicate a substantial, decreasing CFU count due to defensive and simultaneous actions of glycoconjugates compared to spores only used as controls. Decontamination of B. cereus spores was most efficiently and consistently achieved using Galalpha1-->3GalNAcbeta-PAA-flu glycoconjugate under both defensive and simultaneous conditions. Atomic force microscopy (AFM) allowed us to visualize decontamination at the nanoscale level using glycoconjugates. AFM reveals the size of glycoconjugate agglomerates (clusters) and a noticeably different morphology of glycoconjugate-treated spores during decontamination. Morphological features of untreated spores disappear under a thin layer of glycoconjugate solution. This thin layer is formed due to the defensive action of glycoconjugates. Simultaneous action has shown agglomeration of glycoconjugates in solution with B. cereus spores in glycoconjugate suspensions. Glycoconjugates might be useful for the development of an environment-friendly decontaminant of bacterial spores.
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PMID:Defensive and simultaneous actions of glycoconjugates during spore decontamination. 1849 4

Interaction of polystirolsulphonate with polymerization degree of 8 (PSS-8) and polyallylamin PAA (molecular mass 60 kilodaltons) with viruses from bloodline of paramixo- and orthomixoviruses by the example of measles virus, parotitis and flu leads to the decreasing of infective activity. The possible mechanism of viral inhibitive action of these chemical compounds is damaging of interfacial antigenic proteins of paramixo- and orthomixoviruses. In this study it was detected the change of surface tension of bilayer lipid membrane in the presence of PSS-8 and PAA. The change of surface tension leads to disorder in viral proteins adsorption in bilayer lipid membrane. This process could lead to disorder of juncture and self-assembly of virions.
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PMID:[Study of interaction of polystirolsulphonate with polymerization degree of 8 and polyallylamin with bilayer lipids membranes]. 2259 83


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