Penetration of autoantibodies into living cells

Arefyeva A.S.

Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow

The wide diversity of intracellular antigens may serve as targets for autoantibodies in different autoimmune diseases. It was always thought that antibodies could react with their respective antigens exclusively in the extracellular compartment because of inability of large molecules of immunoglobulins to enter into living cells. But a large amount of experimental findings and clinical observations accumulated from the last 20 years indicate that multiple autoantibodies can transit across the cell and nuclear membranes of living cells, participate in the pathogenesis of diverse autoimmune diseases and play a physiological role in healthy individuals. Although the exact mechanism of such autoantibody penetration is discussed in the literature until now, there are several theories explaining the ability of autoantibodies to interact with their intracellular antigens. In this review we represent the most important and interesting observations concerning the ability of autoantibodies to enter into living cells and their nuclei, their possible pathophysiological role in the autoimmune diseases development and mechanism of their living cells penetration.