Prediction of sequential antigenic regions in proteins

AbstractPrediction of antigenic regions in a protein will be helpful for a rational approach to the synthesis of peptides which may elicit antibodies reactive with the intact protein. Earlier methods are based on the assumption that antigenic regions are primarily hydrophilic regions at the surface of the protein molecule. The method presented here is based on the amino acid composition of known antigenic regions in 20 proteins which is compared with that of 314 proteins [(1978) Atlas of Protein Sequence and Structure, vol. 5, suppl. 3, 363-373]. Antigenicity values were derived from the differences between the two data sets. The method was applied to bovine ribonuclease, the B-subunit of cholera toxin and herpes simplex virus type 1 glycoprotein D. There was a good correlation between the predicted regions and previously determined antigenic regions

Polypeptide chains with similar amino acid sequences but a distinctly different conformation. Bovine and porcine phospholipase A2

The primary structures of bovine and porcine pancreatic phospholipase A2 differ only by about 15%. Nevertheless, a 12 residue loop, with only one substitution (Val→Phe) has a quite different conformation, whereas the rest of the molecules have a very similar folding indeed. From this observation it is concluded that prediction of a 3-dimensional structure on the basis of sequence similarity of short segments alone might give erroneous results.

Virus Neutralizing Activity Induced by Synthetic Peptides of Glycoprotein D of Herpes Simplex Virus Type 1, Selected by Their Reactivity With Hyperimmune Sera From Mice

Mice were immunized with synthetic peptides covering the first 56 amino acids of herpes simplex virus type 1 (HSV-1) glycoprotein D (gD) and a fusion protein, produced in Escherichia coli, containing the first 55 amino acid residues of gD. It was found that mice immunized with peptides composed of amino acid residues 1 to 13, 18 to 30. 22 to 38 and 38 to 56 of gD were not significantly protected against a lethal challenge with HSV-1. Immunization with peptide 9-21 and the gD fusion protein resulted in significant protection. Antisera, from mice immunized with HSV-1, were investigated for reactivity with a series of 57 overlapping gD peptides covering the entire amino acid sequence, except for the membrane-spanning region. All antisera reacted with peptides 9-21, 10-24, 151-165, 216-232, 282-301 and with peptide 340-354 located in the anchoring region of gD, and 15 other peptides were recognized by at least one antiserum. Twelve peptides (10-24, 151-165, 216-232, 244-267, 260-274, 270-284, 260-284, 282-301, 300-314, 340-354, 348-362 and 355-369) reacted most frequently with the hyperimmune sera from mice and were selected for further study. These were conjugated to bovine serum albumin and used to immunize rabbits. Only antisera against peptide 10-24, which covers the same epitope as peptide 9-21, neutralized HSV-1 in vitro