Tolerance to dsDNA is achieved through editing of Ig receptors that react with dsDNA. Nevertheless, some B cells with anti-dsDNA receptors escape editing and migrate to the spleen. Certain anti-dsDNA B cells that are recovered as hybridomas from the spleens of anti-dsDNA H chain transgenic mice also bind an additional, Golgi-associated antigen. B cells that bind this antigen accumulate intracellular IgM. The intracellular accumulation of IgM is incomplete, because IgM clusters are observed at the cell surface. In the spleen, B cells that express the heavy and light chains encoding this IgM are surface IgM-bright and acquire the CD21-high/CD23-low phenotype of marginal zone B cells. Our data imply that expression of an Ig that binds dsDNA and an additional antigen expressed in the secretory compartment renders B cells resistant to central tolerance. In the periphery, these B cells may be sequestered in the splenic marginal zone.