BACTERIAL AND PLANT-PRODUCED SCFV PROTEINS HAVE SIMILAR ANTIGEN-BINDING PROPERTIES

A gene encoding a single-chain variable (scFv) antibody fragment was e xpressed as a cytoplasmic and endoplasmic reticulum-targeted protein i n transgenic tobacco plants, In both cases, the scFv accumulated up to 0.01% of total soluble protein (TSP), The same scFv fragment was also produced in the periplasm of Escherichia coli, Measurement of the aff inity by ELISA indicates that the affinity of the bacterially made scF v is about 80-fold lower than that of the parental F-ab fragment, The results suggest that the affinity of the plant-produced scFv fragments is reduced to a similar extent, implying that all the plant-produced scFv fragments are antigen binding.