Fig. 4.

Interaction of the targeted immunotoxin DARP-LoPE with SKOVip-kat cells. (A) – evaluation of DARP-LoPE cytotoxicity in SKOVip-Kat and CHO cells using the MTT assay. Cell viablity in the absence of DARP-LoPE immunotoxin was considered as 100%. (B) – visualization of live cells using the Katushka protein (TurboFP635) and Hoechst 33342 dye; visualization of HER2 receptor expression in SKOVip-kat cells incubated with the monoclonal antibody trastuzumab–FITC and immunotoxin DARP-LoPE–FITC. The excitation and emission wavelengths were as follows: 545/30 and 610/75 nm for Katushka protein, 405/10 and 460/40 nm for Hoechst 33342, and 470/40 and 525/50 nm for FITC, respectively. Scale: 50 μm