Synonyms:8D6, 8D6 antigen, 8D6A, CD320, CD320 antigen, CD320 Molecule, FDC signaling molecule 8D6, FDC SM 8D6, TCblR, Transcobalamin receptor Background:CD320, also known as 8D6, 8D6A or TCblR, is a single-pass type I membrane protein containing 2 LDL-receptor class A domains. Expressed abundantly on follicular dendritic cells (FDCs), CD320 has been shown to enhance proliferation of germinal center (GC) B cells. It is the receptor for cellular uptake of transcobalamin-bound cobalamin. Defects in CD320 are the cause of methylmalonic aciduria type TCblR (MMATC). CD320 has a calculated molecular mass of 29 kDa. This antibody detects bands at 50-55 kDa and 60-70 kDa, probably caused by extensive complex glycosylation.