Date of Award

Spring 1-1-2015

Document Type


Degree Name

Doctor of Philosophy (PhD)


Chemical & Biochemical Engineering

First Advisor

Theodore W. Randolph

Second Advisor

Gregg Nyberg

Third Advisor

Brent Kendrick

Fourth Advisor

Joal Kaar

Fifth Advisor

Stephanie Bryant


Protein aggregates represent a safety, immunological and stability concern in therapeutic protein formulations. Aggregates may be formed at any stage during the manufacturing process, including during cell culture. In mammalian cell culture, the proteins that are produced typically are incubated in the cell culture medium at relatively high temperatures (e.g. 36 ºC) for prolonged periods of time (1-2 weeks). To investigate potential mechanisms by which this incubation might generate protein aggregates, we examined the stability of a model monoclonal antibody (mAb) under cell culture conditions, but in the absence of cells. A step-wise approach was used to eliminate factors that would be causing protein aggregation.

Results show that protein aggregation is mediated by the presence of extracellular monoclonal antibody light chains. This result was corroborated through aggregate characterization showing that a cell lines aggregation propensity correlated with the light chain content of HMWS.