Fig. 3.

Minimizing enrichment of nonspecific yeast in suspension cell-based selections via FACS. Flow cytometry histograms depict an enriched yeast-displayed scFv library binding to target-null mammalian cells. In each plot, the population at left represents unbound mammalian cells, whereas the population at right represents mammalian cells that are bound to yeast. Suspension cell-based selections were carried out using FACS under the following conditions: (i) 2:1 ratio of target-null:target-expressing mammalian cells in the pre-block step (Round 4, 2:1); and (ii) 10:1 ratio of target-null:target-expressing mammalian cells in the pre-block step (Round 4, 10:1). We found that use of the 2:1 and 10:1 ratios led to similar enrichment of nonspecific yeast binders