The capacity of monoclonal anti-DNA antibodies, derived spontaneously from MRL-lpr/lpr mice, to bind directly to intrinsic glomerular antigens and form immune deposits was evaluated. Two antibodies, H130 (IgM-kappa) and H241 (IgG2a-kappa), bound to normal glomeruli in vitro. This binding was not inhibited by DNAase, but it was, in the case of H130, inhibited by the anti-idiotype anti-H130. Both antibodies also bound to glomerular digests on nitrocellulose. After i.v. injection, however, H241 bound to glomeruli and formed glomerular immune deposits, whereas H130 did not. Similarly, after i.p. injection of H241 hybridomas to normal mice, all mice developed glomerular immune deposits. In contrast, administration of H130 hybridomas, other anti-DNA-producing hybridomas, and other unrelated hybridomas did not lead to glomerular immune deposit formation. We conclude that certain lupus auto-antibodies can form glomerular immune deposits by binding directly to non-DNA antigenic structures that are normally present in extracellular locations within normal glomeruli.