Soluble sphingomyelinase from human urine as antigen for obtaining anti-sphingomyelinase antibodies.

A soluble form of lysosomal sphingomyelinase was partially purified from human urine using concanavalin A-Sepharose 4B, Sephadex G-100 and octyl-Sepharose 4B chromatography. The octyl-Sepharose 4B eluate was used to immunise a rabbit. The antiserum obtained was able to precipitate about 70% of the sphingomyelinase activity present in urine from control subjects. Both the immunoprecipitable and non-precipitable activities were found to be deficient in urine from patients with Niemann-Pick disease Type A and Type B. In contrast, both activities were present in urine from patients with Niemann-Pick disease Type C. The antiserum was able to precipitate about 80% of the sphingomyelinase activity present in an aqueous extract of placenta.