Germinal center-B (GC-B) cells differentiate into memory B-cells and plasma cells (PC) through interaction with T-cells and follicular dendritic cells (FDC). CD320 augments the proliferation of PC precursors generated by IL-10. Receptor for the cellular uptake of transcobalamin bound cobalamin.
Expressed abundantly on follicular dendritic cells (FDCs).
Involvement in disease
Defects in CD320 are the cause of methylmalonic aciduria type TCblR (MMATC) [MIM:613646]; also called methylmalonic aciduria due to transcobalamin receptor defect. MMATC is a metabolic disorder characterized by increased blood C3-acylcarnitine levels, elevated methylmalonate and homocysteine, and low uptake of transcobalamin-bound cobalamin, but normal conversion to adenosylcobalamin and methylcobalamin. Plasma vitamin B12 and total homocysteine are normal.