ATTENUATED ANTIGENICITY OF RIBONUCLEOPROTEINS MODIFIED BY REACTIVE OXYGEN SPECIES

Ribonucleoprotein (RNP) particles isolated from fresh goat liver nucle i were exposed to hydroxyl radical which induced modification in the g ross structure of RNP particles. To evaluate the effect of hydroxyl mo dification on the antigenic properties of RNP and possible role of ROS -RNP in the initiation and development of SLE, enzyme immunoassays wer e carried out. SLE sera having high titre anti-DNA antibodies showed e nhanced binding to hydroxyl modified RNP particles in comparison to un modified RNP particles. In competition assay none of the SLE sera or i solated IgG showed preference for ROS-modified RNP particles over nati ve RNP particles. These studies suggest that anti-RNP autoantibodies o bserved in subpopulation of SLE patients are generated by some other i ntra- or extracellular mechanisms and hydroxyl radical has probably no direct role in the initiation of antibodies.