Ammonium chloride slows transport of the influenza virus hemagglutinin but does not cause mis-sorting in a polarized epithelial cell line.

The effects of the weak base ammonium chloride on the intracellular transport and sorting of the influenza hemagglutinin to the apical plasma membrane of polarized epithelial cells were examined in infected Madin-Darby canine kidney cells. Ammonium chloride was found to significantly retard cell surface appearance of the hemagglutinin but to have no effect on either the initial sorting or steady-state levels of hemagglutinin on the apical domain. Based on the rate of acquisition of resistance to endo H, the timed addition of ammonium chloride, and dissociation by reduced temperature incubation of cell surface appearance of the hemagglutinin from early stages of transport and processing, it was determined that the likely site of ammonium chloride action was the trans Golgi.