Influence of Carrier Protein Conjugation Site and Terminal Modification of a GnRH‐I Peptide Sequence in the Development of a Highly Specific Anti‐fertility Vaccine. Part I

Abstract

Immunoneutralization efficacy was attributed to the importance of preserving the GnRH C-terminal.

The hinge region fragment of immunoglobulin G improves immunogenicity of recombinant gonadotrophin‐releasing hormone conjugated to the T‐helper epitope in designing peptide vaccines

“…Active immunization using GnRH-based vaccines has gained widespread acceptance in the treatment of such hormone-associated conditions. 14,15 Because the peptide of GnRH is known to be a weak antigen, immunization required repeated injection of the synthetic immunogens conjugated to a carrier/T-helper epitope. To induce specific antibody responses against GnRH, the choice of an appropriate T epitope as a carrier molecule is very important in designing peptide vaccines.…”

“…Analogues of GnRH have been used clinically to treat a range of hormone‐dependent diseases; however, it is often necessary for large, toxic and expensive drug doses to be administered. Active immunization using GnRH‐based vaccines has gained widespread acceptance in the treatment of such hormone‐associated conditions 14,15 . Because the peptide of GnRH is known to be a weak antigen, immunization required repeated injection of the synthetic immunogens conjugated to a carrier/T‐helper epitope.…”

Part II: Influence of Dimerization of a modified GnRH‐I Peptide Sequence on a Male Antifertility Vaccine

“…Three days after each immunization, tail bleeds were carried out into capillary tubes (Hawksley and Sons Ltd, West Sussex, UK) and the blood centrifuged at 1000 g for 20 min to obtain serum for measurement of antibody levels. The sera were frozen until specific, subclass and competitive enzyme‐linked immunoabsorbent assays (ELISA) were carried out on bovine serum albumin (BSA) : monomer coated plates as described previously 17 …”

“…In the previous paper, 17 we examined the importance of conjugation site through the N‐terminal and C‐terminal of modified GnRH peptides (CHWSYGLRPG‐NH2 and HWSYGLRPGC) to a carrier protein. N‐terminal conjugation was found to induce antibodies of high avidity to free GnRH which were effective in disrupting fertility in mature, male Sprague–Dawley rats.…”

Immunogenicity of Recombinant Maltose-binding Protein (MBP)–Gonadotropin Releasing Hormone I (GnRH-I)

“…However, when this conjugation is through the GnRH-I C-terminal immunocastration was ineffective. The immunoneutralization efficacy was attributed to the existence of preserving the GnRH-I C-terminal [Ferro et al 2002]. The approach described in this applications note utilizes genetic engineering to begin to develop a method to achieve a high immunogenic response while providing a convenient method for the purification of the fusion protein.…”