ACCURATE TOPOLOGICAL COMPARISON OF 2 RECOMBINANT HUMAN GROWTH-HORMONES BY OPTICAL-SURFACE PLASMON RESONANCE

A strategy for the comparison of two recombinant derived human growth hormones (r-hGH) has been developed using surface plasmon resonance (S PR), Statistical analysis was systematically used on the results obtai ned with several batches derived from two different Escherichia coli s trains, Monoclonal antibodies (MAb) directed against four different do mains in the tertiary structure of natural human growth hormone were u sed to compare the epitopic maps of the three (two recombinant and one natural) hGH by SPR analysis, Topological studies show the homogeneit y of the epitopic maps of the three hGH. The kinetic parameters, assoc iation rate, and dissociation rate constants were also analyzed for th e binding of each hGH batch to all MAbs. They were found to be homogen eous between the three hormones, Furthermore, the two r-hGH were compa red by more classical approaches examining recognition of lactogenic o r somatogenic receptors using, respectively, a bioassay of Nb2 cell pr oliferation and binding to rat liver microsomes, Specific bioactivitie s and IC50 values calculated in radioreceptor assays did not significa ntly differ between different r-hGH, The method was sensitive enough t o show slight differences on k(off) value for one MAb (3C11) between ( natural) hormone and two r-hGH, These differences are discussed in rel ation to previous observation made in the literature and the presence of isoforms in the natural product, The strategy developed here was ve ry useful as a new tool to establish the equivalence of the two r-hGH. (C) 1997 Academic Press.