Inhibition of antibody production is specific for αGal. (A) Anti-αGal IgM and IgG Abs in chimeras at 11 to 14 weeks after BMT (before) and following RRBC and MPK cell immunization (shown as RRBC and MPK, respectively) were identified by anti-αGal Ab ELISA. GalT BMT mice did not respond to αGal⁺ xenogeneic cell immunization. GalT-transduced BMT mice (□), REV (•), IR (▴), WT (▪), KO (○) (n = 5 each). (B) Complement-mediated cytotoxicity assay demonstrating cytotoxicity by non–anti-αGal xenoantibody in GalT BMT mice. (C) Anti-PAEC Abs assessed by ELISA. GalT BMT mice produce xenoantibodies to pig cells. Data are shown as mean ± SE.