Figure 6.

Human IgG2κ mAb-F readily crystallizes at neutral pH both in vitro and in the ER. (A) Glass vial containing 70 mg/ml mAb-F solution at pH 5.0 (left) and after pH shift to pH ∼7.0 (right). (B) DIC micrograph of the precipitated materials recovered from the bottom of vial-2. (C) Western blotting results for the cell culture media and cell lysates harvested on Day-7 post transfection. The expression constructs used for transfection are shown at the top of each lane. (D) Western blotting results on the cell culture media after 24 hr period of BFA or null treatment from Day-2 to Day-3 post transfection. The cell viabilities after the 24 hr BFA and mock treatment were 93.3% and 95.4%, respectively. (E) Fluorescent micrographs of HEK293 cells co-transfected with HC and LC constructs. Cells under null treatment are shown in the first row. Cells under BFA treatment are shown in the second and third rows. Cells containing readily identifiable crystalline bodies are marked by arrowheads. Green, anti-gamma staining. Red, anti-kappa staining. (F) Fluorescent micrographs of HEK293 cells transfected with HC construct (top 2 rows) or with LC construct (third row). Green, anti-CD147 staining. Red, anti-gamma or anti-kappa staining.