CD77
CD77 is not a protein antigen but the glycosphingolipid globotriaosylceramide (Gb3), carrying the Pk blood group carbohydrate structure. Detected by monoclonal antibodies on germinal center B cells, it is a classical Burkitt lymphoma marker and defines a distinctive CD77-positive B cell subset. CD77 functions as the cell-surface receptor for Shiga toxin of Shigella dysenteriae and for verotoxins of enterohemorrhagic Escherichia coli, explaining the renal and cerebral tropism of hemolytic uremic syndrome. In keeping with its lipid nature, CD77 clusters in lipid rafts and modulates signaling, and CD77 antibodies have been explored in lymphoma therapy research.
