Figure 5

The RES and FcγRIIb are relevant to stradomer-mediated protection against ITP. (A) Mice were pretreated with 2A-2Hc or IgG2a Fc for 1 day before injection of fluorescently labeled, opsonized red blood cells (oRBCs) to test whether pretreatment protects against clearance of circulating oRBCs by the RES. Data shown as percentage-labeled oRBCs/percentage-labeled oRBCs at 3 minutes × 100 (*Significant with Bonferroni adjustment for the six comparisons indicated; n = 12 mice/group pooled from two separate experiments including these specific treatment groups). (B) To determine whether the stradomer-mediated protection against ITP in mice is dependent on FcγRIIb, 2A-2H_C and 2A-ILZ_N were tested simultaneously in C57/Bl6 mice with functional FcγRIIb (left) and in FcγRIIb^-/- mice (right) (*Significant with Bonferroni adjustment for the six comparisons indicated. N = 17 to 18 mice per group, except 2A-ILZ_N (n = 6), pooled from three separate experiments, one of which included the 2A-ILZ_N stradomer).