Rapid detection and characterization of sialic acid-specific lectins of Helicobacter pylori.
A particle agglutination assay (PAA) using fetuin (Ft) covalently coupled to carboxylate-modified latex (CML) particles was evaluated for rapid detection of sialic acid-specific haemagglutinins/lectins (SALs) of Helicobacter pylori isolates which bind sialoglycoconjugates. Sixty-three percent (20/32) of the isolates examined gave a positive PAA test. Cell-bound SALs were extracted by washing the bacteria with deionized water or isotonic saline, and their expression was influenced by pH and culture conditions. The Ft-CML reactivity of the PAA-positive isolates was inhibited by bovine submaxillary mucin, transferrin, fetuin, orosomucoid, vitronectin and lactoferrin in a manner which suggested that the isolates contain a lectin recognizing the alpha(2-6) linkage of terminal sialic acid. Western blots of strain NCTC 11637 SALs probed with horseradish peroxidase (HRP)-labelled Ft identified three bands (MW 64 kD, 62 kD, 56 kD) which also reacted with HRP-labelled mucin, transferrin, lactoferrin, orosomucoid, vitronectin and laminin. Sera from patients with a H. pylori infection and one polyclonal rabbit antiserum (strain NCTC 11637) also reacted with the SALs. Immunogold labelling of a polyclonal rabbit antiserum raised against the 64 kD protein of strain NCTC 11637 that reacted strongly with Ft-CML showed that abundant SALs were loosely cell-associated with the cell surface of both spiral and coccoidal forms of H. pylori. SALs were also present in low amounts on the surface of strain NCTC 11638 and 66, a clinical isolate that did not react with Ft-CML.
Lelwala-Guruge
J
J
Department of Medical Microbiology, University of Lund, Sweden.
Ascencio
F
F
Ljungh
A
A
Wadström
T
T
D000818:Animals; D002240:Carbohydrate Sequence; D002417:Cattle; D004926:Escherichia coli / Q000737:chemistry; D006001:Glycoconjugates / Q000032:analysis*; D006023:Glycoproteins; D016480:Helicobacter pylori / Q000737:chemistry* / Q000254:growth & development / Q000648:ultrastructure; D006386:Hemagglutination Tests; D006388:Hemagglutinins / Q000032:analysis*; D007841:Latex Fixation Tests; D037102:Lectins / Q000032:analysis*; D008969:Molecular Sequence Data; D009211:Myoglobin; D011817:Rabbits / Q000276:immunology; D012794:Sialic Acids / Q000032:analysis; D013211:Staphylococcus aureus / Q000737:chemistry; D000509:alpha-Fetoproteins
D006001:Glycoconjugates; D006023:Glycoproteins; D006388:Hemagglutinins; D037102:Lectins; D009211:Myoglobin; D012794:Sialic Acids; D000509:alpha-Fetoproteins