Anti-DNA antibodies react with DNA expressed on the surface of monocytes and B lymphocytes.

It is becoming increasingly apparent that nuclear antigens can be expressed on the surfaces of certain cells. We provide evidence that anti-DNA antibodies are reactive with DNA on the surface of monocytes and B lymphocytes. The DNA isolated from monocytes sedimented in a 17.8S position, corresponding to a molecular weight of 4.6 X 10(6); it was mainly double-stranded with many short single stranded regions. In one patient with active systemic lupus erythematosus experiments indicated that anti-DNA antibodies had interacted in vivo with the cell surface DNA on monocytes. The functional significance, if any, of these findings remains to be determined.