FIG 4.
Selection for adaptive mutations to improve the yield of K188-del PIVNS2A production. (A) Experiment flowchart. The diagram shows the procedure for continuous passaging of PIVNS2As on NS2A-expressing BHK-21 cells. (B) IFA of NS2A-expressing BHK-21 cells infected with P0 and P30 PIVNS2As. The cells were stained for E protein expression (red) using MAb 4G2. (C) Summary of adaptive mutations. The complete genomes of P30 PIVNS2As were sequenced for each of the four independent selections. The adaptive mutations are indicated by the amino acid positions encoded by individual genes. Consensus sequencing was performed to identify the adaptive mutations. The titers of P30 PIVNS2As are also indicated.