Production of recombinant Growth Hormone Receptor Antagonist in Nicotiana Tabacum cells serves as a model for production of O-Glycosylated Arabinogalactan proteins in plant cell culture. Data presented indicates efforts involved in process development as well as process optimization, leading to a 10-100 fold increase in protein titers. Experimental design and strategy involved a good understanding and implementation of the pilot scale and large scale manufacturing conditions, such as mixing, dissolved oxygen and air flow. Process development was also carried out with a view to simplifying the downstream processing requirements. As a result of comprehensive understanding and integrated process development efforts, results obtained show identical titer progression at all three levels, namely, lab scale, pilot scale and manufacturing scale.