Echinococcus granulosus: antigen characterization by chemical treatment and enzymatic deglycosylation.
Parasite antigenic fractions obtained by biochemical purification of sheep hydatid fluid were subjected to enzymatic digestion. The relative mobilities of the 5 and B antigens, before and after treatment, were analyzed by polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot. Antigenic fractions transferred to nitrocellulose were also treated with sodium metaperiodate and concanavalin A. The results indicate that antigen 5 contains a substantial amount of carbohydrates covalently linked to a polypeptide backbone, which strongly bind to concanavalin A and is removed by N-glycosidase F (PNGase F). Antigen 5 possesses complex N-linked oligosaccharides (PNGase F sensitive), without terminal N-acetyl-D-glucosamine residues (N-acetyl-D-glucosaminidase nonsensitive) and has no high-mannose oligosaccharides (endo-beta-N-acetylglucosaminidase H nonsensitive). In contrast, the antigen B of low molecular weight is not susceptible to either enzymatic digestions (PNGase F, Endo H, and N-acetyl-D-glucosaminidase) or sodium metaperiodate oxidation and it does not bind to concanavalin A. Polyclonal antibodies prepared against the two antigens reacted with the deglycosylated antigen 5 in Western blot. The dominant epitopes are, therefore, polypeptides, although the presence of carbohydrate epitopes in the native glycoproteins cannot be excluded.
March
F
F
Servei de Microbiologia, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
Enrich
C
C
Mercader
M
M
Sánchez
F
F
Muñoz
C
C
Coll
P
P
Prats
G
G
D000118:Acetylglucosaminidase / Q000378:metabolism; D000818:Animals; D000947:Antigens, Helminth / Q000032:analysis* / Q000737:chemistry / Q000276:immunology; D003208:Concanavalin A / Q000378:metabolism; D004446:Echinococcus / Q000276:immunology*; D000939:Epitopes / Q000276:immunology; D006023:Glycoproteins / Q000276:immunology*; D006031:Glycosylation; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase / Q000378:metabolism
D000947:Antigens, Helminth; D000939:Epitopes; D006023:Glycoproteins; D003208:Concanavalin A; D000118:Acetylglucosaminidase; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase