Antibodies to complementary peptides as probes for receptors

Peptide hormones initiate their physiological responses by binding to receptor proteins embedded in the plasma membranes of their target cells. Mechanisms accounting for specific protein-protein interactions, such as peptide hormone binding by cell receptors or epitope binding by antibody have not been defined. A fundamental tenet of the immunological network hypothesis is the generation of anti-idiotypic antibodies to epitopes located in the hypervariable regions of antibody evoked in the same animal species. Anti-idiotypic antibodies to antibodies to peptide hormones with specificity for epitopes involving antibody binding sites may mimic the actions of the peptide hormone by binding to receptors and evoke cell responses associated with the hormone. A provocative relationship was identified in the genetic code, which recognized that complementary codons for strongly hydrophobic amino acids code for strongly hydrophilic amino acids. This led to the proposal and then to demonstration that peptide pairs based on the nucleotide sequences of complementary codons bind one another. It was then proposed that immunization with complementary peptides to peptide hormones may produce antibodies which, analogous to anti-idiotypic antibodies, may mimic the hormone. Some antibodies to complementary peptides for peptide hormones have been shown to mimic the peptide hormones by binding to their receptors and evoking cell responses characteristic of those of the hormones. Exploiting these relationships, some antibodies to complementary peptides for peptide hormones have been used to identify, purify, and characterize receptor proteins for peptide hormones. Polypeptide hormones initiate their characteristic physiologic effects by binding to specific receptor proteins located on the plasma membranes of their target cells.(ABSTRACT TRUNCATED AT 250 WORDS)