| Protein therapeutics are used to treat a wide range of diseases with significant benefits to patients. Aggregation of the product is a significant challenge to the successful commercialization of biopharmaceuticals because aggregates can cause harmful immune responses in patients. Even the most stable proteins can be susceptible to aggregation induced by solid surfaces, particles, and stress at the air-water interface. There are also reports that shear can cause protein aggregation. In this work we investigated the effects of these stress factors on the stability of a monoclonal antibody. We found that tungsten contamination caused formation of visible particles in pre-filled syringes. The protein interacted in surprising ways with glass and cellulose but these materials were not destabilizing. However, stainless steel did cause formation of soluble aggregates. In well-controlled studies we found that aggregation and formation of particles at the air-water interface was most affected by the compression of the interface but only weakly dependent upon the interface exposure rate or the bulk protein concentration. Finally, during these studies we developed a novel fluorescence method for probing the structure of adsorbed proteins that may be a useful tool for studying proteins bound to vaccine adjuvants. |
