Radiolabeling of human immune interferon with 125I-labeled Bolton-Hunter reagent

Developments and recent advancements in the field of endogenous amino acid selective bond forming reactions for bioconjugation

Bioconjugation methodologies have proven to play a central enabling role in the recent development of biotherapeutics and chemical biology approaches. Recent endeavours in these fields shed light on unprecedented chemical challenges to attain bioselectivity, biocompatibility, and biostability required by modern applications. In this review the current developments in various techniques of selective bond forming reactions of proteins and peptides were highlighted. The utility of each endogenous amino acid-selective conjugation methodology in the fields of biology and protein science has been surveyed with emphasis on the most relevant among reported transformations; selectivity and practical use have been discussed.

Preparation and characterization of labelled interferon-gamma and the development of radioreceptor assay for interferon-gamma

A 125I-labelled recombinant interferon-gamma (IFN-gamma) was prepared by the lactoperoxidase-glucose oxidase method. The specific activity of the labelled IFN-gamma was 31 Bq U-1 and its molecular weight, immunoreactivity and receptor binding ability remained the same after the labelling. Using the labelled IFN-gamma and FL5(-1) cells from human amniotic membrane, a radioreceptor assay was developed. Natural IFN-gamma, recombinant IFN-gamma and the labelled IFN-gamma were observed to bind to the same binding sites on the cells with similar affinity (Kd = 1.3-2.2 x 10(-10) M). The radioreceptor assay was more specific than a bioassay because the labelled IFN-gamma did not compete with IFN-alpha or IFN-beta. It was much more sensitive (90 pM) than conventional competitive radioimmunoassay (300 pM) using the same labelled IFN-gamma, and as sensitive as immunoenzymometric assay (60 pM). The radioreceptor assay should be useful not only for research on IFN-gamma but also for the determination of biological activity in process control and/or quality control of IFN-gamma manufacturing.