Antibody-antibody competition binding assay.

(A) hESCs were preincubated with biotinylated 297-D4 in the presence of isotype control antibody and 144-A8 prior to the addition of phycoerythrin-conjugated streptavidin. (B,C) hESCs were preincubated with α-BAP31 in the presence of isotype control antibody, 297-D4 (B), 144-A8 (C) prior to the addition of FITC-conjugated anti-rabbit IgG. Antibody binding to hESCs was then analyzed by flow cytometry. The percent of binding inhibition was calculated from mean fluorescence intensity. Statistical analysis used the Student’s t-test (*p<0.05; **p<0.001).