B cells from autoimmune NZB mice were transferred into unmanipulated non-autoimmune NZB.xid mice. The number of antibody-producing cells against various antigens in recipient mice was monitored at varying time after cell transfer using ELISPOT assay. NZB B cells producing antibody against all antigens we examined were able to proliferate in NZB.xid mice, which supports the idea of polyclonal B cell activation. However, anti-DNA producing cells proliferated most rapidly, and anti-BrMRBC producing cells proliferated more rapidly than B cells of other antigenic specificities. The percentage of anti-DNA producing cells in total immunoglobulin-producing cells increased over time whereas the percentage of anti-ovalbumin producing cells kept the same level. This indicates directly the preferential proliferation of NZB anti-DNA producing cells in NZB.xid mice. The result shows the responsibility of antigen-specific stimulation or activation on autoimmunity in the context of polyclonal B cell activation.