Abstract
A sensitive radioimmunoassay for rabbit immunoglobulin allotypes has been developed. Separation of antibody‐bound and free antigen was accomplished by salt precipitation with ammonium sulfate, followed by collection and wash on glass fiber filters by means of a semi‐automatic cell harvester. The efficiency of the collection was increased by the addition of nonionic detergent which was salted out together with the precipitated reagents. The presentation of the a1 allotype, located in the VH region, was found to be different on IgG and IgA molecules.