Single-Chain Anti-DNA Fv

Antibodies to native B-DNA are common in systemic lupus erythematosus (SLE), and their measurement serves as a diagnostic and prognostic marker of the disease (1 ). Autoreactive antibodies are also found in the sera of normal individuals (2 ). Natural autoantibodies crossreact with a variety of conserved, and seemingly unrelated, autoantigens. Most of these antibodies are of low affinity, although rare exceptions of high affinity natural anti-DNA antibodies have been reported (3 ). The role of cells that make natural autoantibodies and whether they are progenitors of cells that make disease-associated autoantibodies remains unclear (4 ).