Fig. 1: SARS-CoV-2 DNA vaccine.
From: Preclinical evaluation of a candidate naked plasmid DNA vaccine against SARS-CoV-2
a DNA vaccine construct pNTC-Spike; full length, human codon optimized SARS-CoV-2 spike sequence cloned into expression vector NTC8685-eRNA41H with significant vector features indicated. b Protein expression from the DNA vaccine candidate was confirmed by DNA lipofection into Vero E6 cells followed by western blotting using anti-S1 (left) and anti-S2 (right) detecting mouse monoclonal antibodies S1-1047 and S2-1254, respectively. Lanes: (1) SARS-CoV-2 infected Vero E6 extract (2) Spike expressing plasmid (commercial positive control), (3) pNTC-Spike, (4) NTC vector control, and (5) VERO E6 (negative control). Lower panels show the 42 kDa β-actin expression as loading control. Full-length Spike protein and Spike S1/S2-fragments are indicated with solid arrows and brackets, respectively. All blots derived from the same experiment and were processed in parallel. Raw, uncropped blots are presented in Supplementary Fig. 2. c Expression of pNTC-Spike-derived SARS-CoV-2 spike protein in Vero E6 cells, visualized by immunofluorescent labeling. Forty-eight hours after transfection, cells were incubated with either the anti-S1 mouse monoclonal antibody S1-1047 (top panel) or anti-S2 mouse monoclonal antibody S2-1254 (bottom panel) followed by a goat anti-mouse IgG Alexa Fluor 488 conjugate for detection (green). Cell nuclei were counterstained with DAPI (blue). Size scale bar: 20 µm.
