PEPTIDE IMMUNOGEN MIMICRY OF A PROTEIN-SPECIFIC STRUCTURAL EPITOPE ON HUMAN CHORIOGONADOTROPIN

It is a challenge to construct synthetic immunogens that elicit antibodies (Abs) both directed to conformational epitopes and specific for a complex protein like human choriogonadotropin (hCG). A monoclonal antibody specific for hCG bound to regions around Lys45 of the α subunit (hCGα) and Asp112 of the β subunit (hCGβ). A peptide comprising residues 46 to 55 of hCGα and residues 106 to 116 of hCGβ elicited Abs in rabbits that were directed to a discontinuous epitope and were specific for hCG. These Abs inhibited the binding of hCG to its receptor. Thus, a synthetic immunogen can mimic a conformational-specific epitope and can be useful for vaccine development.