In an effort to use plant biotechnology for the production of biopharmaceuticals, pollens collected from lily (Lilium longiflorum) were grown in vitro and transformed with a PCR-amplified 1.7 kb cDNA encoding human tissue plasminogen activator (tPA) using Agrobacterium via a vacuum infiltration process. Western blotting showed that transgenic lily pollen tubes selected on kanamycin for 16 hrs expressed a tPA protein with a size similar to the human standard, suggesting their possible use as a disposable host for rapid foreign protein production.