Biochemical characterisation of an epitope on the surface membrane antigen (Cs-gp200) of the pathogenic piscine haemoflagellate Cryptobia salmositica Katz 1951.
A protective surface antigen (200 kDa) on C. salmositica was detected using a monoclonal antibody (mAb-001). Enzymatic studies on the epitope indicated that it was sensitive to nonspecific protease K and to site-specific trypsin and protease V8 but not to alpha-chymotrypsin. The reactivity of the epitope with mAb-001 was not affected when the antigen was denatured with 8 M urea; however, reduction of the antigen with dithiothreitol destroyed the epitope. The epitope was susceptible to sodium m-periodate oxidation and N-glycosidase F, but not to O-glycosidase or neuraminidase. It was also sensitive to mild potassium hydrochloride hydrolysis and to phospholipase C, which is specific for phosphatidylinositol. These results suggest that the epitope consists of a polypeptide, a carbohydrate, and probably a phospholipid. The asparagine-bound N-glycosidically linked hybrid-type carbohydrate chain has the minimum length of a chitobiose core unit. There is probably a phosphatidylinositol residue which anchors the polypeptide to the surface membrane. The antigen is extensively posttranslationally modified.
Feng
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Department of Zoology, University of Guelph, Ontario, Canada.
Woo
P T
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D000581:Amidohydrolases / Q000378:metabolism; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000953:Antigens, Protozoan / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D000954:Antigens, Surface / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D002918:Chymotrypsin / Q000378:metabolism; D019286:Endopeptidase K / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D056890:Eukaryota / Q000276:immunology*; D006026:Glycoside Hydrolases / Q000378:metabolism; D006868:Hydrolysis; D017686:Oncorhynchus mykiss; D010084:Oxidation-Reduction; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D011134:Polysaccharides / Q000737:chemistry; D012697:Serine Endopeptidases / Q000378:metabolism; D014357:Trypsin / Q000378:metabolism; D010738:Type C Phospholipases / Q000378:metabolism; D014508:Urea / Q000378:metabolism
D000911:Antibodies, Monoclonal; D000953:Antigens, Protozoan; D000954:Antigens, Surface; D000939:Epitopes; D011134:Polysaccharides; D014508:Urea; D010738:Type C Phospholipases; D006026:Glycoside Hydrolases; D012697:Serine Endopeptidases; D002918:Chymotrypsin; C028344:glutamyl endopeptidase; D014357:Trypsin; D019286:Endopeptidase K; D000581:Amidohydrolases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase