Magnetic solid-phase enzyme immunoassay for the detection of anti-glomerular basement membrane antibodies

A new enzyme immunoassay has been developed for the demonstration of antiglomerular basement membrane antibodies. Magnetically responsive polyacrylamide-agarose beads (Magnogel) activated with glutaraldehyde were used to bind sonicated insoluble rat glomerular basement membranes. Both the collagenous and the non-collagenous moieties were demonstrated to be fixed on the beads. Sera from brown Norway rats with anti-glomerular basement membrane antibodies induced by HgCl2 injections were incubated with the beads. After washing, the fixed rat IgG were revealed using alkaline phosphatase labelled Fab fragments from anti-rat IgG sheep, IgGs. Comparison with a radioimmunoassay showed that results were reliable. This enzyme immunoassay has several advantages which may render this assay of considerable clinical usefulness.