Partial characterization of two antigens secreted by L1 larvae of Trichinella spiralis.
Two protein antigens were isolated from excretory-secretory products of Trichinella spiralis by biochemical methods and characterized with respect to their chemical and immunological properties. One antigen, of apparent Mr 43,000, is an abundant secreted protein of infective L1 larvae, while the other, of 45-50 kDa, is present in smaller amounts. Yields, extinction coefficients, isoelectric points, amino acid compositions, and partial N-terminal amino acid sequences for each are reported. Partial amino acid sequences of peptides derived from the 43-kDa protein by cyanogen bromide cleavage have been determined. Treating a reduced-pyridylethylated derivative of the 43-kDa protein with glycopeptidase F (N-glycanase) resulted in formation of a transient product of 37 kDa followed by a stable polypeptide of 32 kDa (by SDS-PAGE), suggesting the presence of two N-linked carbohydrate groups. A similar result was obtained with the 45-50-kDa protein, which gave a transient doublet of 38 and 40 kDa and a final, stable product of 33 kDa, with a minor component of 35 kDa. Two glycosylation sites of the 43-kDa protein and one site of the 45-50-kDa protein can be identified in the amino acid sequences. Polyclonal antibodies prepared against the two proteins cross-reacted extensively, but failed to react with the doubly deglycosylated polypeptides in Western blots. The dominant epitopes present in the reduced-pyridylethylated polypeptides are, therefore, N-linked carbohydrate, although the presence of peptide epitopes in the native proteins cannot be excluded.
Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032.
A M
AM
Gold
D D
DD
Despommier
S W
SW
Buck
D000581:Amidohydrolases / Q000378:metabolism; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000909:Antibodies, Helminth / Q000276:immunology; D000947:Antigens, Helminth / Q000032:analysis*; D015153:Blotting, Western; D002851:Chromatography, High Pressure Liquid; D003429:Cross Reactions; D003488:Cyanogen Bromide; D004591:Electrophoresis, Polyacrylamide Gel; D006031:Glycosylation; D015801:Helminth Proteins / Q000276:immunology*; D007526:Isoelectric Point; D008969:Molecular Sequence Data; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D014234:Trichinella / Q000254:growth & development / Q000276:immunology*
D000596:Amino Acids; D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D015801:Helminth Proteins; D000581:Amidohydrolases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D003488:Cyanogen Bromide