Shown are recycling experiments under two protocols. A. Recycling detected by increased sensitivity of endocytosed biotinylated-CD22 to MESNa treatment over time. This assay was conducted on BJAB, Daudi, and Reh cells as illustrated by Steps C-E in Fig. 7. The difference in intensity between MESNa treated and untreated samples after recycling indicates the extent of recycling. B. Recycling detected by capture of recycled biotinylated CD22 with streptavidin magnetic beads prior to lysis. BJAB, Daudi, and transfected CD22 or Siglec-F in CHO cells were tested as illustrated in Steps C,D, and F from Fig. 7. Western blots were developed with αCD22 for all B cell lines, and with αV5 for the CHO cell lines.