FIGURE 4: Time course measurement for the production and secretion of recombinant RBD. (A) Schematic overview and expected mass of the secreted RBD fusion proteins. (B) Western blot analysis with an antibody against the RBD domain of RBD fusion variants 1 and 2 in the cell-containing pellet fraction (P) and supernatant fraction (S) following tetracycline induction of the according L. tarentolae liquid cultures for the indicated time periods. An induced culture without plasmid served as negative control (n.c.) and recombinant RBD as positive control (p.c.). The calculated masses from panel A are indicated. (C) Western blot analysis with antibodies against the C-terminal His tag (left) or the RBD domain (right) of fusion variant 3.