FIG 4 .

Anti-CK8 antibodies block Pet binding to the plasma membrane and the cell damage caused by Pet. HEp-2 cells pretreated with anti-CK8 antibody for 30 or 45 min were then washed and treated with Pet (37 µg/ml) for 3 h. Unintoxicated cells and cells intoxicated without antibody treatment were used as controls. All cells were washed, fixed, permeabilized, and stained with rhodaminated phalloidin for F actin (red), TO-PRO 3 for DNA (blue), and anti-Pet antibodies followed by a secondary anti-rabbit IgG antibody labeled with fluorescein (green). Slides were observed by confocal microscopy. When cells were incubated with the anti-CK8 antibody alone, no effects on HEp-2 cells were observed (data not shown).