Transient plant production of Salmonella Typhimurium diagnostic antibodies

Kopertekh, Lilya; Meyer, Torsten; Freyer, Cornelia; Hust, Michael

The amount of recombinant proteins expressed in agroinfiltrated N. benthamiana leaves as measured by ELISA was 82.5 mg/g fresh weight for scFv-TM43-E10 and 45.9 mg/g fresh weight for scFv-Fc-TM43-E10. These accumulation levels are not superior to protein expression levels shown for the movement-competent deconstructed virus vectors [53] . However, the yields are comparable to the expression levels described for movementdeficient virus vectors and non-viral vectors [54] . Our transient expression system might be improved by directing scFv-Fc-TM43-E10 recombinant antibody into various cell compartments, particularly endoplasmatic reticulum (ER). Several studies demonstrated that the addition of a KDEL peptide to recombinant proteins has allowed efficient ER targeting and increased their accumulation in 2-10 times [37, 55, 56] . The expression profile in transient assay may be different for each product expressed. In most cases maximal expression levels occur at 3-5 days after infiltration and fade rapidly after 7-9 days. For example, the maximal accumulation for GFP, P24 and SARS-CoV proteins has been observed at 3 dpi [51, 57] . The highest expression level for L2 and non-structural HIV-1 Nef proteins was reached at 5 dpi and 9 dpi, respectively [45, 57] . In our study scFv and scFv-Fc formats of TM43-E10 antibody displayed a similar expression profile with highest accumulation level at 5-7 dpi.