ABSTRACT
Human pituitary hormones have been classified into three structural categories: proteins, glycoproteins, and peptides. The protein hormones represent a family with structural and functional homologies, comprising growth hormone (hGH), chorionic somatomammotropin (hCS), and prolactin (hPRL). The most effective antibodies were obtained from guinea pigs or rabbits immunized against ovine PRL, thus indicating a closer antigenic relationship between man and nonprimate mammalian species for PRL than for GH and CS hormones. Although antibodies served as invaluable tools for sensitive immunoassays, their use for immunochemical analysis of the antigenic structure of hormones was limited by the heterogeneity of antibody specificities in conventional antisera. Thus, monoclonal antibodies (MAb) secreted by hybridoma cell lines indicated an opportunity of a novel and more advanced approach towards the various yet unresolved questions. Since the MAb-hGH immune complexes were soluble in antibody excess, it was of interest to determine their spectrotypes. Fragments of hGH or hCS obtained from extensive tryptic or CNBr cleavage were devoid of antigenicity.
