Subcellular localization of viral proteins in hCoV-NL63 infected CaCo-2 and LLC-MK2 cells by immunofluorescence assay. Confocal laser scanning microscopy on CaCo-2 (A) and LLC-MK2 cells (B) infected with hCoV-NL63. Left panels: staining with anti-ORF 3 and anti-M protein rabbit antisera (only in B) and detection by fluorescein isothiocyanate (FITC)-labelled goat-anti-rabbit antibody (green). Middle panels: detection of co-staining of the same cells with mouse-anti-ERGIC-53 mAB (Axxora) and detection with rhodamine-labelled goat-anti-mouse antibody. Yellow signals in merged pictures (right panels) show colocalization. Bars represent 20 μm.