Introduction

Figure 1 shows a subconfluent monolayer (~50% of plastic surface covered with cells) of Chinese hamster ovary (CHO) cells with typical morphology under low magnification using phase-contrast microscopy (10X objective). The white round refractile structures are dead CHO cells that have detached from the plastic surface.

Figure 2 shows a subconfluent monolayer of CHO cells under high magnification using phase-contrast microscopy (40X objective). Note the intracellular refractile organelles.

Methods

The phase-contrast microscopic images show the typical cellular morphology of CHO cells grown for 5 days in vitro in cell culture medium. The CHO cells were cultivated at 37^oC under 5% CO₂ in Ham’s F-12 medium containing 5% fetal calf serum.

Discussion

CHO cells are a continuous mammalian cell line used in industrial settings to express recombinant proteins for research and therapeutic applications.