scholarly journals Role of Anti-gB and -gD Antibodies in Antibody-Induced Endocytosis of Viral and Cellular Cell Surface Glycoproteins Expressed on Pseudorabies Virus-Infected Monocytes

Virology ◽  
2000 ◽  
Vol 267 (2) ◽  
pp. 151-158 ◽  
Author(s):  
Herman W. Favoreel ◽  
Hans J. Nauwynck ◽  
Patrick Van Oostveldt ◽  
Maurice B. Pensaert
1991 ◽  
Vol 99 (3) ◽  
pp. 485-495
Author(s):  
SUPAVADEE AMATAYAKUL-CHANTLER ◽  
MICHAEL A. J. FERGUSON ◽  
RAYMOND A. DWEK ◽  
THOMAS W. RADEMACHER ◽  
RAJ B. PAREKH ◽  
...  

Developmental studies of the changes in protein glycosylation are useful in elucidating the role of oligosaccharides in biological events. We have used the chemical technique, hydrazinolysis, to release oligosaccharides from cell surface glycoproteins of Dictyostelium discoideum. Oligomannose type, xylose- and fucose-containing oligosaccharides were found to be present. The charged oligosaccharides contained sulphate and mannose 6-phosphate residues; no sialic acid was detected. The charged oligosaccharides also contained significant amounts of xylose, arabinose, fucose and galactose, as well as mannose and N-acetylglucosamine, which were the main constituents of the neutral glycans. By monitoring the chemical characteristics of the liberated oligosaccharides, dramatic changes in both the charge and size distribution of cell surface oligosaccharides were observed throughout the 24 h period of cell development. A comparison, however, between the neutral glycan structures of prestalk and prespore cells, over the same time frame showed no dramatic differences Discoidin, a lectin present on the cell surface of 8 h cells, was found not to be glycosylated. Affinity chromatography using immobilised discoidin was used to probe a sugar library made from the cell surface glycoproteins of 8h cells. Discoidin was found to bind selectively an oligosaccharide with the structure Manα3(Manα6)(Xylβ2)Manβ4GlcNAc. This oligosaccharide lacks a conventional N,N'-diacetylchitobiose core and has only been previously observed in plant glycoproteins. Peptide-N-glycosidase F treatment of horseradish peroxidase released an identical structure, confirming that the oligosaccharide was not a degradation fragment of the hydrazine. The oligosaccharide was found to inhibit discoidinmediated haemagglutination with a Kt of 0.75 mM, a concentration approximately 100 times lower than that for galactose The correlation between changes in the amoebal plasma membrane oligosaccharide structures and the biological events occurring at different stages of development such as cell-cell adhesion and cellsubstratum attachment suggest an important role for sugars in these processes


2002 ◽  
Vol 76 (13) ◽  
pp. 6845-6851 ◽  
Author(s):  
Herman W. Favoreel ◽  
Geert Van Minnebruggen ◽  
Hans J. Nauwynck ◽  
Lynn W. Enquist ◽  
Maurice B. Pensaert

ABSTRACT Pseudorabies virus (PRV), a swine alphaherpesvirus, is capable of causing viremia in vaccinated animals. Two mechanisms that may help PRV avoid recognition by the host immune system during this viremia are direct cell-to-cell spread in tissue and antibody-induced internalization of viral cell surface glycoproteins in PRV-infected blood monocytes, the carrier cells of the virus in the blood. PRV glycoprotein B (gB) is crucial during both processes. Here we show that mutating a tyrosine residue located in a YXXΦ motif in the gB cytoplasmic tail results in decreased efficiency of cell-to-cell spread and a strong reduction in antibody-induced internalization of viral cell surface glycoproteins. Mutating the dileucine motif in the gB tail led to an increased cell-to-cell spread of the virus and the formation of large syncytia.


1992 ◽  
Vol 101 (3) ◽  
pp. 625-633
Author(s):  
H. Asaga ◽  
K. Yoshizato

The role of glycochains of cell surface glycoproteins in the cell to collagen interaction was examined by studying the effect of lectins on the fibroblast-mediated collagen gel contraction. Lectins of Phaseolus vulgaris agglutinin (PHA), concanavalin A (ConA), lentil seed agglutinin (LCA), pea agglutinin (PSA), Ricinus communis agglutinin-60 (RCA), and wheat germ agglutinin (WGA) dose-dependently inhibited gel contraction, while lectins of mushroom agglutinin (ABA), peanut agglutinin (PNA), pokeweed mitogen (PWM), and soybean agglutinin (SBA) did not. Of these lectins, PHA seemed to be worthy of further analysis, because PHA, but not other lectins, inhibited spreading of fibroblasts on collagen fibrils but not on plastic or gelatin, suggesting that cell-surface glycoproteins responsive to the lectin are involved in the specific binding of fibroblasts to native collagen fibrils. The inhibitory effect of PHA-E4, an isolectin of PHA, was more intense than that of PHA-L4, another isolectin of PHA. The collagen gel contraction was also inhibited by tunicamycin and monensin in a concentration-dependent and reversible manner. These results strongly suggest that PHA-E4-reactive glycoproteins of the fibroblast surface play an important role in cell to collagen binding during the gel contraction. Five membrane proteins including beta 1 subunits of the integrin family were obtained by affinity chromatography with PHA-E4.


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