Staining pattern produced by anti-Ro60 antibodies

Human serum containing antibodies directed against Ro60 did not stain the nuclei of the traditional HEp-2 cell substrate (green, panel A). Human anti-Ro60 antibodies did stain the nuclei of cells using the HEp-2000 substrate, which has been genetically engineered to overexpress the protein in approximately 20 percent of the cells (red, panel C). Anti-Ro60 antibodies produced a nucleolar and nuclear speckled pattern in transfected cells. The human serum did not stain cells that did not overexpress Ro60. DAPI staining in panels B and D (blue) indicates the location of nuclei. White arrows in C and D identify HEp-2000 cells over-expressing Ro60. Human serum containing anti-Ro60 antibodies was provided by the Centers for Disease Control and Prevention from the international ANA reference serum panel.