title: Production and characterization of monoclonal antibodies to the carboxyl-terminal heptapeptide of endothelin-1.
abstract: Two cell lines, RR5.ET-1 and RR1.ET-1, that produce monoclonal antibodies specific for the carboxyl-terminal heptapeptide of endothelin-1 (ET-1) have been cloned and stabilized. An RIA was developed to facilitate the evaluation and characterization of these monoclonal antibodies. The affinity constant of each MAb for ET-1, as determined by Scatchard analysis, was 5.74 x 10(8) M-1 for RR5.ET-1 and 4.15 x 10(7) M-1 for RR1.ET-1. The antibodies reacted specifically with the carboxyl-terminus (ET15-21) and did not cross-react with the amino-terminal amino acids (ET1-16). As expected, the antibodies cross-reacted with endothelin-2 (ET-2) and endothelin-3 (ET-3), and to a lesser extent, with the closely related sarafotoxins. Both MAbs retained about 55% reactivity with the ET-1 terminal sequence of Asp-Ile-Ile-Trp (ET18-21) but had no reactivity with the ET sequence His-Leu-Asp-Ile-Ile-Trp-Val-Asn (ET16-23) nor with Big ET-1 (ET1-39). These data strongly suggest that the terminal four amino acids of ET-1 are included in the MAb binding site. More importantly, the terminal Trp21 must be free, not linked to Val22 to retain reactivity with either of the MAbs.
authors.affiliation: Diagnostics Drug Discovery, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, NJ 08543.
authors.forename: M
authors.initials: M
authors.lastname: Frosco
authors.forename: J
authors.initials: J
authors.lastname: Johnstone
authors.forename: J
authors.initials: J
authors.lastname: Olivieri
authors.forename: R V
authors.initials: RV
authors.lastname: Romero
authors.forename: J I
authors.initials: JI
authors.lastname: Tu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000302:isolation & purification; D000915:Antibody Affinity; D000918:Antibody Specificity; D003429:Cross Reactions; D016232:Endothelins / Q000276:immunology*; D006825:Hybridomas / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C / Q000276:immunology; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000276:immunology*; D011863:Radioimmunoassay
chemical_list: D000911:Antibodies, Monoclonal; D016232:Endothelins; D010446:Peptide Fragments