Abstract
This chapter focuses on the importance of plants as an innovative, speedy, flexible and economical system for developing and producing monoclonal antibody (MAb)-based human biologics for infectious disease and cancer. The recent development of deconstructed virus-based vectors that have allowed rapid and high-level transient expression of MAbs in plants is presented. The progress in plant glycoengineering that allows plants to produce MAbs with superior efficacy and safety than other traditional systems is described and the combined advantages of these new breakthroughs, which have promoted the plant expression system to become a premier platform for the commercial development and production of human biologics, are discussed in the context of several leading MAb-based biologics.