FIG. 3.

Confirmation of protein expression in Sf9 cell pellets by Western blotting and fusion protein-based IFA. (a and d) Guinea pig anti-N195 protein serum; (b and e) guinea pig anti-Sc protein serum; (c and f) human SARS-CoV-positive serum. Lane 1, N195 recombinant baculovirus-infected cells; lane 2, Sc recombinant baculovirus-infected cells; lane 3, N195-Sc fusion baculovirus-infected cells. Each antiserum sample with SARS-CoV-infected Vero cells (d to f) and mock-infected cells (j to l) was examined under a fluorescence microscope for its reactivity pattern. In order to show clearly that the antisera reacted only with infected cells and not with adjacent uninfected cells, side-by-side images of the same field were viewed under a light microscope (g to i) and an immunofluorescence microscope (d to f).