Porcine Mx1 expression alters the spatial distribution of structures bearing the early endosome autoantigen 1 (EEA1). Early endosomes were immunostained by sequential incubation with a mAb targeting EEA1 and with an Alexa 488-conjugated goat anti-mouse IgG. Numerous distinct bright granules are visible in non-induced cells, corresponding to early endosomes. Only a diffuse, “dusty” pattern is seen when poMx1 is expressed.