Increased sensitivity of PIGA^- RBCs to complement-mediated lysis. (A) Expression of GPI-linked proteins on RBCs from FL, GL, and wt control animals. RBCs were stained with a fluorescent-labeled monoclonal antibody against CD24, a GPI-linked surface antigen highly expressed on normal RBCs. FL cells lack CD24, whereas a proportion of GL RBCs have some residual CD24 expression. (B-C) Lysis of wt, FL, and GL RBCs by heterologous complement. (B) Activation of rat complement was induced by the classical pathway (antibody sensitized RBCs) or (C) by the alternative pathway. RBCs from FL and GL mice were more sensitive to lysis by heterologous complement, activated by either pathway (FL > GL > wt). Data represent mean ± SD.