Pierre Rivaille

Synthesis of LH-RH using a new phenolic polymer as solid support and “BOP” reagent for fragment coupling

Abstract p-Hydroxyphenyl propionic resin (Table I, compound 4) was used to prepare the 1–6 protected fragment of LH-RH which was then condensed with “BOP” (benzotriazolyl N-oxytrisdimethylaminophosphonium hexafluorophosphate) as coupling reagent to the 7–10 residue synthesized on the same resin. Peptidylresin was divided into two aliquots in order to obtain LH-RH after aminolysis and treatment with liquid hydrogen fluoride, LH-RH-COOH after saponification followed by hydrogenation, or treatment with liquid hydrogen fluoride. The resulting hormones were rapidly purified by the sole means of two gel filtrations.

Epitopes of the 44–68 human parathyroid hormone fragments: The importance of specific hydrophilic peptide sequences

Several pentapeptides included in the 44-68 sequence of human parathyroid hormone (hPTH) were synthesized simultaneously on benzhydrylamine and m-nitrobenzhydrylamine resins. The first polymer gave the free peptide and the second the peptidyl-resin complex. An ELISA test carried out with each peptidyl-resin complex showed that all the anti-44-68 hPTH antibodies raised in different animal species are directed against the same hPTH pentapeptidic sequence. This sequence is very hydrophilic and is specific to the hormone. This study demonstrates the importance of specific peptide chains in an epitope.

Characteristics of guinea-pig immune sera elicited by a synthetic diphtheria toxin oligopeptide.

Several oligopeptides of different lengths contained within the Cys 186-Cys 201 first disulfide loop of the diphtheria toxin molecule have been synthesized by a solid-phase method. 125I-labeled rabbit antibodies raised against diphtheria toxin reacted specifically with oligopeptides linked to m-nitrobenzhydrylamine resin when the amino acid chain length was equal to or greater than 10 residues. The synthetic tetradecapeptide (STDP) corresponding to the sequence Gly 188-Cys 201 was used to immunize guinea-pigs. The immune sera obtained reacted with the whole diphtheria toxin molecule as judged by an antigen-linked immunosorbent assay. Anti-STDP sera exhibited a clear, albeit limited, neutralizing effect against the lethal action of diphtheria toxin on cultivated Vero cells. The anti-STDP sera were also able to partially block the ADP-ribosylation of elongation factor 2 mediated by whole diphtheria toxin. In contrast, anti-STDP sera were almost inactive on the enzymic activities of either toxin fragment A or crm 45, a mutant protein which lacks the 15,000 mol. wt C-terminal sequence of the toxin molecule. On the basis of the results obtained, a possible localization of the Cys 188-Cys 201 loop region on the toxin molecule is proposed.