Expression of monoclonal antibodies for functional and structural studies

Monoclonal antibodies are a mainstay of the research laboratory, with increasing focus on human IgG that best reflects the human antibody response and allows swift transition to therapeutic monoclonal development. The technologies to express human IgG in the laboratory are increasingly accessible, allowing researchers in diverse fields to produce human monoclonals for functional and structural studies. In this chapter, we provide an overview of the considerations for expressing recombinant IgG, with reference to detailed protocols and reputed sources for reagents. These recombinant antibodies can then be evaluated in functional assays, specific to their antigen targets and disease state. We further provide the major steps for preparing these monoclonals for X-ray crystallography, to determine their structure, often in complex with their target antigen. Considering there are > 1500 human IgG structures available, we also provide a detailed review on the characteristics of these structures, and their immunoglobulin variable gene usage. Overall, this chapter intends to serve as a resource, and to highlight the progress in structural studies of human IgG monoclonals.