Antibody-induced decreases in the level of detectable antigen reflect antigen-specific removal and not RBC internalization. (A-C) Forty-eight hours posttransfusion into PBS, anti-KEL–, or anti-HEL–treated recipients, HOD × KEL RBC were stained for the level of detectable KEL antigen (A), HEL antigen (B), or Ter119 antigen (C). (D) HOD × KEL RBC ghosts or ghosts from nontransfused mice (NT) were analyzed by western blot by probing for KEL, HEL, and glyceraldehyde 3-phosphate dehydrogenase (GAPDH). (E-G) HOD × KEL RBC were incubated with anti-KEL or anti-HEL antibodies in vitro at 4°C and 37°C for the indicated time and assessed for expression of KEL (E), HEL (F), and Ter119 (G) antigens by flow cytometry. Data in panels A-D and panels E-G are reflective of 2 independent experiments. ****P < .0001 and ns by 1-way ANOVA with Tukey multiple comparison test.