FIGURE 2.

Endoglycosidase of Streptococcus pyogenes (EndoS)‐imlifidase reduces donor‐specific antibodies (DSA)‐mediated killing of donor bone marrow cells (BMC) in sensitized recipients. A‐C, Naive NOD mice were immunized with FVB splenocytes 4 weeks prior to the administration of EndoS‐imlifidase. Sera were harvested prior to immunization, prior to and 4 h after enzyme treatment. Representative histograms on the left are for DSA‐IgG Fc (panel A), DSA‐IgG₁ Fc (panel B), DSA‐IgG₃ Fc (panel C), and DSA‐IgG₃ heavy chain (panel D) with sera at a 1:25 dilution. Mean fluorescence intensity (MFI) of DSA in the titrated sera is shown on the right. Mean ± SEM are shown. Ratio paired t test was used to compare MFI of DSA before and after enzyme treatment at each serum dilution with *P < .05, **P < .01. D, Schematic of the experiment shown in E,F. Naive NOD mice were immunized with B6.CD45.1 splenocytes 4 weeks prior to injection of T cell–depleting mAbs. EndoS‐imlifidase was administrated 2 d post‐T cell depletion. Four hours after enzyme treatment, NOD mice were injected with 80 million B6.CD45.2 BMC intravenously. Splenocytes and BMC were analyzed for the expression of MHC‐I H‐2K^b and CD45.2. E,F, Shown are representative dot plots of the four different treatment groups (on the left) and the percentage of donor cells (on the right, mean ± SEM). One‐way analysis of variance with Holm‐Sidak's multiple comparisons were used to compare values between the three sensitized groups with *P < .05