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. Author manuscript; available in PMC: 2014 Jun 15.
Published in final edited form as: Adv Drug Deliv Rev. 2012 Oct 23;65(6):782–799. doi: 10.1016/j.addr.2012.10.005

Fig. 7.

Fig. 7

Evaluation of stability of antigens in lyophilized lettuce after prolonged storage. (a) Western blot analysis to evaluate stability of lyophilized anthrax protective antigen (PA) expressed in lettuce leaves after storage at room temperature for 2 (1), 4 (2), and 6 (3) months. PA, standard (100 ng), WT, untransformed lettuce. (b) PA stability after 3 months of storage, and lyophilization for different durations: (1) 24, (2) 48 and (3) 72 hrs. (c) Western blot analysis of fresh (F) and lyophilized (L) leaves expressing PA. Total soluble protein (10 µl) was loaded on an equal quantity basis (50 mg from each sample were extracted in 300 ul of extraction buffer) to examine the increase of PA content after lyophilization. (d) Fold increase of specific antigen after lyophilization. PA, lettuce transplastomic plant expressing PA; CTB-Pins, lettuce transplastomic plant expressing CTB-Proinsulin; white bar, fresh material; grey bar, lyophilized material. (e) Evaluation of long-term stability of PA in lyophilized lettuce leaves after storage at room temperature for 15 (1), 13 (2), 3 months (3), and 1 week (4). F, fresh leaf; total soluble protein (20 ng) was loaded in each lane for immunoblot assay. (f) Microbial burden of leaves expressing PA. 1, fresh leaf; 2, lyophilized leaf; 3, commercially available freeze-dried alfalfa capsules. © Plant Biotechnology Journal, Society for Experimental Biology, Association of Applied Biologists and Blackwell Publishing Ltd, Plant Biotechnology Journal (2012): In Press [25].