A3B protein upregulated in A12- and C2-infected cells is nuclear. HBEC3-KT cells were infected with HAdV-A12, -B3, -C2, or mock control. A3B (in green) and hexon protein (in red) expressions were assessed by fluorescence microscopy at 4 dpi. HBEC-A3B was used as positive control and displayed a strong A3B expression with a nuclear distribution. A3B protein levels in mock- and B3-infected cells were similar to background. Strong and moderate A3B signals, respectively, were observed in the nucleus of cells infected with the A12 and C2 strains.