Six Facts About Monoclonal Antibody Unfolding and Aggregation

The drug development sector has long been interested in research regarding monoclonal antibodies. Why? These antibodies and the ways in which they respond to the molecules of disease (antigens) have a significant impact on the strategies scientists use to develop drugs that fight disease. Engineering monoclonal antibodies can lead to the development of medicines that work against targeted diseases.

While studying how monoclonal antibodies work, it is also essential to understand the circumstances in which they become unstable. This guide to monoclonal antibodies will address facts regarding their basic properties, how they are used to fight diseases, and a few important facts about how they unfold and aggregate. 

Fact 1: Monoclonal antibodies are clones.

The name of monoclonal antibodies is significant-these antibodies are immune cells that are cloned from one unique parent immune cell. As a result, all monoclonal antibodies bind to and target only one part of a singular antigen. By contrast, polyclonal antibodies will bind to and target multiple parts of more than one antigen, depending on the origins of each. 

Fact 2: Monoclonal antibodies can be engineered to become more effective.

Part of drug development involves the cloning and manipulation of monoclonal antibodies. Since researchers can now produce monoclonal antibodies that bind to, interact with, and purify any substance known to man, most of this research is geared toward isolating the specific antigens targeted by each antibody. Other tactics include engineering monoclonal antibodies to become bispecific, allowing each to target two different antigens. 

Fact 3: Monoclonal antibodies can become unstable. 

As monoclonal antibodies are developed and manipulated for drug research, their concentrations are also altered to suit the desired effects of each drug. Therapeutic monoclonal antibodies are often formulated with concentrations of 150g/L or more, which can affect the stability of the proteins within. In this case, researchers must stabilize the protein to ensure each antibody or drug continues to have its desired effect. 

Fact 4: Researchers use differential scanning fluorimetry to study monoclonal antibodies.

Recently, researchers endeavored to study the behavior of monoclonal antibody proteins in high concentrations. To do so, fragments of antibodies were investigated using differential scanning fluorimetry and turbidity measurements. Researchers exposed each to differing concentrations of proteins under varying temperatures and noted the level of chemical, conformational, and colloidal stability.

Fact 5: When proteins in monoclonal antibodies become unstable, they interact differently.

Researchers found that with increasing concentrations, instability causes proteins to react conformationally. This means that the amino acid chains forming the protein's structures unfold and potentially expose different, hydrophobic parts of the proteins. These proteins are then attracted to surrounding proteins and may gather and aggregate together. As concentration increases, the probability of such aggregations increases.

Fact 6: Protein aggregations can negatively affect drug efficacy.

As concentrations rise and the potential for aggregation increases, aggregations can also increase in size. This can occur in particularly stressful storage conditions with high temperatures or pressures. Such large aggregations affect the solubility of the drug and can even affect viscosity, making the drug too thick to inject. As such, drugs negatively affected by aggregation may not be able to continue development as injectables. 


Future ImplicationsAs researchers continue to develop potentially lifesaving therapeutic monoclonal antibodies, special care must be taken to prevent undesirable protein unfolding. Guidelines regarding ideal protein concentrations can guide stable therapeutic development and proper storage protocols for injectable drugs will help ensure continued stability after production. Overall, the area of monoclonal antibody study promises further leaps in the formulation of stable therapeutics to treat a variety of antigens.