Concanamycin B is a macrolide antibiotic that selectively inhibits vacuolar type H+-ATPases, also known as V-ATPases (IC50 = 5 nM). In this way, it blocks the acidification of vacuolar organelles as well as early to late endosomal transport. Concanamycin B interferes with bone resorption and maturation of CD8 T lymphocytes. It also prevents processing of major histocompatibility complex (MHC) class II precursors in human B cells, inhibiting the expression of MHC class II molecules on the cell surface.
