{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Malanosome HMB45 antibody reacts against premelanosome protein gp100 present in immature melanosomes, cutaneous melanocytes, prenatal and infantile retinal pigment epithelium and melanoma cells. gp100 is a 100 kD membrane bound glycoprotein present in stage I premelanosome, stage II and nonmelanized stage III melanosomes but absent in stage IV melanosomes and melanosomes in keratinocytes. This antibody was generated from an extract of melanoma. It reacted positively against melanocytic tumors but not other tumors, thus demonstrating specificity and sensitivity. Moreover, this antibody reacts positively against junctional nevus cells but not intradermal nevi, and against fetal melanocytes but not normal adult melanocytes."}]}]}