To examine the effect of JGF on SARS-CoV-2 infection, we initially developed a fluorescence-based cell-cell fusion assay in which BHK cells that express SARS-CoV-2-spike protein and EFGP act as the effectors, and Calu-3 cells expressing endogenous hACE2 act as targeting cells because SARS-CoV-2 cell infection depends on ACE2 and TMPRSS2 (Hoffmann et al., 2020). The gene discussed is TMPRSS2; the disease is infection.