Fig. 1
From: Efficient oral vaccination by bioengineering virus-like particles with protozoan surface proteins
Resistance to degradation of protozoan CXXC-rich proteins. a High magnification representative images of trophozoites from Giardia lamblia, Entamoeba histolytica, Tetrahymena thermophila, and Paramecium tetraurelia, and non-adherent mammalian cell (NS0) incubated for 90 min with high trypsin concentration (20 mg ml−1). The top panel shows phase contrast images. Bottom panel shows live (green cytoplasm) and dead (red nucleus) images of the same cells stained with fluorescein diacetate and propidium iodide. The bars represent 25 μm. b, c Recombinant proteins were expressed in insect cells and highly purified by affinity chromatography. Western blotting analysis of the effects of extreme pH, trypsin (T), intestinal extract (IE), and stomach extract (SE) on recombinant proteins. Proteolytic profile of ΔVSP1267 and HA. Representative images are on the left; densitometric measurements are on the right (mean ± s.e.m.) (b). Proteolytic profile of recombinant ΔVSPH7 and ΔVSP9B10 (c). d Proteolytic profile of native VSP1267 compared to an unrelated parasite protein, GRP78/BIP and native VSPs from Giardia lysates. e Trypsin digestion of ΔVSP1267 subjected to different pre-treatments to modify its structure. The ratio protein:trypsin (P:T) is expressed as w-w. Dilutions of IE and SE are indicated on top. *p < 0.05, **p < 0.01; Student’s t-test, n = 4 from two independent experiments. Source data are provided as a Source Data file
