The antigenic structure of the human glycoprotein hormone α-subunit: III. Solution- and solid-phase mapping using synthetic peptides

Twenty-seven synthetic peptides, representing the entire structure of the human glycoprotein hormone α-subunit were used to map the antigenic structure of the α-subunit. Solution phase and solid phase assays were performed with these peptides and a panel of eight monoclonal antibodies (MAb). Two dominant regions were localized between residues 22-37 and 70-87. All eight antibodies recognized these regions, but differed somewhat with respect to whether they saw the more N-terminal, middle, or C-terminal portions of these regions. The sequence of residues 13-22 was recognized by three MAbs. The C-terminal region from residues 84-92 was recognized by three MAbs. All MAbs recognized conformational epitopes in that they reacted with two or more regions. Three MAbs (two against free α and one against human CG) have linear amino acid sequences as part of their conformational epitope.