Precipitin reaction between Sda-active human Tamm-Horsfall glycoprotein and anti-Sda-serum

Human Tamm-Horsfall glycoprotein isolated from an Sd(a+) donor, with high Sda inhibitory activity, was labelled with 14C-formaldehyde. The labelled glycoprotein was precipitated by anti-Sda sera. A good correlation was found between the precipitating and agglutinating titers of different anti-Sda sera.