Fig. 2.

Expression and purification of SΔTM in silkworm larvae. (A) Expression of S protein and SΔTM in silkworm larvae. Each expressed proteins in hemolymph were detected by western blot using a mouse anti-c-Myc monoclonal antibody. (B) Purification of SΔTM from hemolymph using affinity chromatography. Purified SΔTM was detected by CBB staining and western blotting. (C) TEM image of purified SΔTM. Proteins were stained with phosphotungstic acid as a negative stain. (D) ELISA to analyze the binding of purified SΔTM to its receptor. Human DPP4, human ACE2 and BSA were immobilized onto wells in a 96-well plate. ELISA was performed according to the protocol described in the Materials and Methods.