Cultured human endothelial cells display an antigen that is recognized by certain human anti-chromatin autoantibodies.

Certain human anti-nucleosome autoantibodies cross-reacted specifically with an antigen on the surface of human vascular endothelial cells. This was shown by two different techniques. First, antibodies eluted from the surface of cultured endothelial cells bound to cell nuclei; this binding was inhibited by soluble mononucleosomes. Second, X-ANA, specifically isolated by their affinity to polynucleosomes, stained the plasma membranes of single cell suspensions of endothelial cells in the indirect immunofluorescence test. Several lines of evidence excluded Fc receptor-mediated binding of Ig to the cells. Thus, plasma membranes of vascular endothelial cells and chromatin bear an antigen that is serologically related.