Radioimmunoassay of human IgG, IgA and IgM

Radioimmunoassay procedures for the quantitation of nanogram quantities of human immunoglobulin are described. The techniques have been successfully used to measure immunoglobulin secretion in culture supernatants by cultured human lymphocytes. Compared with previously published assays to assess lymphocyte function in vitro these procedures are simple, quick and reliable. A comparison of double-antibody and solid-phase radioimmunoassay is made. Similar sensitivity and variability in IgG and IgA assays were observed but it was not possible to develop a reliable double antibody radioimmunoassay for IgM. The solid-phase assay has several advantages over the double-antibody radioimmunoassays being quick to perform and using standard commercial reagents without necessity for exhaustive absorption.