SCID mouse platelets are more immunogenic compared with the platelets of BALB/c mice. CBA recipient mice were transfused weekly with titrations of either (A) control transfusions with BALB/c MC, (B) BALB/c mouse platelets, or (C) platelets from anti-AsGm1–treated SCID mice and their sera tested for antidonor antibodies. The data is expressed as the percentage of mice responding (n = 20) by detection of IgG antidonor antibody during the transfusion protocol. Each line represents a group of mice receiving: (A) (◊) 10⁶, (○) 10⁵, (□) 10⁴, and (▹) 10³control MC per transfusion; (B) (◊) 10⁸, (○) 10⁷, and (□) 10⁶ BALB/c platelets per transfusion; (C) (◊) 10⁸, (○) 107 and (□) 10⁶ antibody-treated SCID platelets per transfusion, (X) 10⁸ platelets from antibody nontreated SCID mice. For B and C, the numbers in brackets correspond to the number of MC transfused with the platelets.