Specificities of antibodies to human growth hormone (hGH) in patients treated with hGH: longitudinal study and comparison with the specificities of animal antisera.

The specificities of human and animal antibodies (Abs) against human GH (hGH) were analyzed using competition experiments with five monoclonal antibodies to hGH (MAbs). The results indicate that 1) the Abs produced by patients receiving long term hGH therapy as well as Abs of goat, rabbit, and mouse origin recognized the various hGH epitopes defined by the MAbs; 2) the proportion of each Ab population, with a given specificity, differed markedly in different patients and also with time in the same patient; 3) the titer of certain Ab populations was very low in some patients, and 4) polyclonal mouse Abs and some human Abs enhanced the binding of [125I] hGH to insolubilized MAbs.