STRUCTURAL AND IMMUNOLOGICAL CHARACTERIZATION OF FRIEND MURINE LEUKEMIA-VIRUS GLYCOPOLYPEPTIDE USING SYNTHETIC OLIGOPEPTIDES

Using terminal position, hydrophilicity, predicted reverse turns and type specificity as criteria, 5 oligopeptides were selected for synthesis from the amino acid sequence of the envelope glycopolypeptide gp70 of Friend murine leukemia virus. These peptides corresponded to the amino acids 6-12 (pep1), 124-131 (pep2), 256-262 (pep3), 283-290 (pep4) and 434-441 (pep5). After coupling to carriers, bovine serum albumin or keyhole limpet hemocyanin, antisera were prepared in rabbits. All 5 oligopeptides were immunogenic; pep1, pep2, pep4 and pep5 were able to elicit antibodies to the native glycopolypeptide. These sequence-specific antisera distinguished between glycoproteins of different leukemia viruses. At least 3 of the selected peptides, the type-specific oligopeptides pep3, pep4 and pep5, were found to be natural epitopes of gp70.