The morbillivirus cellular receptor cN4 is not expressed in DBCCs. (A) Noninfected Vero-cN4 cells and regular Vero cells as well as noninfected (not shown) and infected DBCCs were stained with an anti-human nectin-4 antibody. Immunofluorescence analyses indicated a clear signal exclusively in cells expressing nectin-4. Representative fields of view were pictured using an inverted confocal fluorescence microscope (magnification, ×100; FluoView FV1000; Olympus). (B) cN4 mRNA is not detected in noninfected (not shown) or infected DBCCs. Total RNA was extracted from noninfected Vero, Vero-cSLAM, and Vero-cN4 cells as well as from infected DBCCs and subjected to RT-PCRs to investigate the expression of the housekeeping gene GAPDH and the A75/17 H (CDV H), cN4, and cSLAM genes.