The Silver Locus Product (Silv/gp100/Pmel17) as a New Tool for the Analysis of Melanosome Transfer in Human Melanocyte–Keratinocyte Co-Culture

In the 2008 study, researchers introduced a novel in vitro assay to track melanosome transfer from melanocytes to keratinocytes using the silver locus product (Silv/gp100/Pmel17). The assay, which employed double immunofluorescence to detect gp100 in melanin granules, allowed for the quantification of melanin transfer and was validated with known inducers and inhibitors of melanocyte activity. The findings demonstrated that melanosome transfer can occur through cytophagocytosis and directly via filopodia, with the assay confirming the role of filopodia as a direct conduit for melanin transfer. The study did not involve human subjects but used human skin samples from Caucasian donors with skin photo-type II. The assay is expected to be useful for understanding melanosome transfer mechanisms and evaluating melanocyte modulators.