Antibody fragments can affect product quality and may be difficult to effectively remove through downstream purification, particularly when fragmentation is associated with the molecular design or structural characteristics of the protein.
In this project, the antibody exhibited a relatively high fragment level during protein expression. Since purification alone could not adequately reduce the fragment content, Protheragen implemented a targeted cell culture process optimization strategy to control fragmentation at the upstream stage.
The molecular design and structural complexity of the antibody contributed to fragment formation during protein secretion.
The major challenges included:
After extensive cell line screening, no candidate cell line was able to sufficiently resolve the high fragment content. Therefore, the development strategy shifted toward process-level control of fragmentation using a selected cell line with comparatively favorable performance.
Protheragen applied a targeted process development strategy to control antibody fragmentation at the cell culture stage.
Multiple cell lines were evaluated to identify a comparatively suitable candidate for subsequent process development. Although cell line screening alone did not sufficiently reduce fragmentation, selection of an appropriate cell line provided a suitable foundation for further process optimization.
The culture medium formulation was optimized to support cell growth and protein expression while helping control fragment formation during the culture process.
Key cell culture parameters were systematically optimized to improve process control over antibody fragmentation. The optimized conditions were evaluated for both fragment content and antibody expression, ensuring that fragment reduction was achieved without compromising productivity.
The customized upstream process effectively reduced antibody fragment levels while improving antibody expression.
50% Reduction in Fragment Content
Following optimization of the culture medium and cell culture process parameters, the antibody fragment content was reduced by approximately 50%, meeting the established quality control requirements.
Figure 1. Comparison of antibody fragment levels before and after upstream process optimization.
Increased Antibody Expression
Importantly, fragment reduction was achieved together with an increase in antibody expression. This result demonstrates that the optimized upstream process improved product quality without compromising, and potentially enhancing, production performance.
Figure 2. Comparison of antibody expression before and after upstream process optimization.
| Development Objective | Result |
|---|---|
| Control antibody fragmentation | Fragment content reduced by approximately 50% |
| Meet product quality requirements | Fragment level met established quality control requirements |
| Maintain production performance | Antibody expression was improved |
| Establish a suitable upstream process | Customized media and cell culture conditions were developed |
The project demonstrated that upstream cell culture process optimization can provide an effective approach for controlling antibody fragmentation when downstream purification and cell line screening alone are insufficient.
By combining cell line selection with customized media formulation and cell culture process optimization, Protheragen reduced antibody fragment content by approximately 50% while simultaneously improving expression. The optimized process met the required quality control criteria and provided a suitable foundation for further antibody process development and manufacturing.
