Fig 1.

Tissue tropism of HCoV-EMC in human bronchus and lung. Bronchial (A to C) and lung (E to G) tissues were infected with HCoV-229E, HCoV-EMC, and SARS-CoV. At 24 hpi, the tissues were fixed and tissue sections were stained for human coronavirus N protein (reddish brown), as described in Materials and Methods. Viral replication kinetics in ex vivo cultures of bronchial (D) and lung (H) biopsy tissue specimens infected with 10⁶ TCID₅₀s/ml of coronaviruses were determined by virus titration at 37°C. The bar charts show the mean and the standard error of the mean of the virus titer pooled from at least three independent experiments. Asterisks indicate a statistically significant increase in viral yield compared to that at 1 hpi: *, P < 0.05; **, P < 0.005; ***, P < 0.0005.