Abstracto

Monitoring vaccine protein glycosylation: analytics and recent developments

John F Cipollo

In recent years, it has become increasingly clear that glycosylation of key pathogen glycoprotein antigens can significantly affect antigenic properties. For example, pathogens, such as human immunodeficiency virus and influenza, can develop a “glycoshield” over key antigens as they passage through host populations. In addition to shielding of antigenic sites key changes in glycosylation have been shown to modify host innate immune responses and both of these phenomena can potentially impact vaccine performance. A better understanding of glycosylation properties of vaccine antigens may better guide development of these products and management of their production processes. Due to the complexity of oligosaccharides, the analysis of these glycosylation states has been difficult and time consuming. With the advent of cutting edge mass spectrometry based techniques many of the barriers to glycan and glycoprotein analysis have been lowered. Combined with traditional techniques such as high field NMR, GC/MS, CE-LIF, and HPLC analyses, these new technologies now make it feasible to monitor glycosylation through vaccine development and during the manufacturing process. This situation can allow for better defined and controlled vaccine products that contain these chemical entities. In this review the major analytics that can be used in these analytical platforms are discussed in relation to rational for their use in vaccine products. A brief review of protein glycosylation is provided as is a discussion of the basic biology behind and examples of how glycosylation processes influence host immunity. Also discussed are special considerations when choosing cell substrates and fermentation processes for production of these vaccines. A range of analytical techniques are discussed along with the information that can be derived from each and their advantages and drawbacks. Information is provided in order to guide the reader towards the choice of a series of methods that combine to provide the structural information desired ranging from basic glycan compositional information to detailed fine structure of glycans and on protein site specific glycosylation patterns.