Figure 2
For each of the constructs listed, the E. coli growth media or the HEK 293 cell culture media was removed and tested for β-lactamase activity. Cell lysates from the HEK 293 cells were obtained to assay for the expression of an active β-lactamase fusion protein. The ability of the clone to survive the carbenicillin challenge is indicated by (+). Detection of β-lactamase in the media or cell lysate is also indicated by (+). In the CD4 fusion construct, a (-/+) sign indicates that only a small percentage (0.1%) of tested clones survived the carbenicillin challenge.
