Discordance of SSA/Ro and SSB/La cellular antigens in synchronized cells.
SSA/Ro and SSB/La are soluble cellular proteins to which antibodies are frequently produced in patients with Sjögren's syndrome and systemic lupus erythematosus. In this investigation, we examined anti-SSA/Ro and anti-SSB/La staining patterns on synchronized WiL2 cells and mixed lymphocyte culture cells using monospecific antisera. In addition to its presence in the nucleoplasm, the SSB/La antigen was highly concentrated in the nucleolus of cells during the late G1 and early S phase and is thus cell cycle-related. In contrast, the SSA/Ro antigen was found to be independent of cell cycle, showing a nuclear speckled pattern in all phases. Blocking experiments indicated that free SSB/La is responsible for the nucleolar staining, whereas the combination of both SSA/Ro and SSB/La determines the nucleoplasmic speckled staining pattern.
D000974:Antibodies, Antinuclear / Q000276:immunology; D000918:Antibody Specificity; D001324:Autoantigens / Q000032:analysis / Q000276:immunology*; D001667:Binding, Competitive; D002451:Cell Compartmentation; D002453:Cell Cycle; D002460:Cell Line; D005455:Fluorescent Antibody Technique; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins; D012859:Sjogren's Syndrome / Q000276:immunology; D000097585:SS-B Antigen; D000099207:SS-A Antigen
D000974:Antibodies, Antinuclear; D001324:Autoantigens; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins; D000097585:SS-B Antigen; D000099207:SS-A Antigen; C116006:RO60 protein, human