Figure 3.

Alloimmunization to human glycophorin A (hGPA) RBCs is abrogated upon blocking CD40L, a co-stimulatory molecule. (A) Serum anti-hGPA IgG at day 14 post-transfusion represented as adjusted mean fluorescence intensity (MFI) in mice treated with MR1 or isotype antibody during primary transfusion. (B) Serum anti-hGPA IgG after primary transfusion (7 days before secondary transfusion) and 14 days after secondary transfusion. (C) Splenic germinal centers (GL7⁺ CD95⁺ B-cells) 8 days after secondary RBC exposure. (D) Serum anti-KEL IgG after primary KEL transfusion in naïve animals or in those previously treated with MR1 or isotype-matched control antibody during prior hGPA transfusion. *p < 0.05 determined by Mann–Whitney U test or ANOVA. Data are representative of at least two experiments (n = 3–5 mice per group per experiment).