The properties of antibody against smooth endoplasmic reticulum of melanocytes.

The smooth endoplasmic reticulum (smooth-surface membrane, SSM) is quite similar in properties to the cytoplasmic which is known to be antigenic. SSM of the melanoma melanocytes can be isolated from the mouse melanoma as a reasonably pure preparation and it contains tyrosinase. Rabbits were immunized by the SSM isolated from Harding-Passey mouse melanomas. Formation of the antibody was detected by the double immuno-diffusion method. Anti-SSM-serum thus formed was found to react with cytoplasmic membrane in the immunofluorescent test, and also showed the specific cytotoxicity to the mouse melanoma cells. On the other hand, the tyrosinase activity of SSM was not inhibited by this antiserum.