We conducted proteomics analysis aimed at evaluating the differences between CHO cell lines expressing 2G12 and 353/11, cells were cultured using a semi-perfusion batch process in parallel. The cells were collected and pelleted on day six, four hours after medium exchange, when both cell lines had reached maximum density and exhibited sustained viability (Figure 1). One cell line exhibited high production (353/11), whereas the other one (2G12) displayed low production. To induce endoplasmic reticulum (ER) stress, 353/11 cells were cultivated separately and parallelly treated with tunicamycin (TM) at a final concentration of 1 µg/mL in fresh cultivation medium for four hours prior to harvesting. This approach aimed to establish uniform experimental conditions comparable to those of non-treated cells.